The answer is a resounding YES! – Twitter just isn’t about folks posting what they had for lunch, or where they are going after work. (OK, there are still some who post like that…) But for the most part Twitter is a tool that Wireless LAN Professionals can use to help you in your career, help in your educational pursuits, and even with your Wireless Network Troubleshooting issues.

Like many other things in life, what you receive from Twitter is directly related to how much effort you put into it. You can make Twitter be as helpful, or as useless as you want.

I’ve been using Twitter for years, and it has been a fantastic place to learn more about Wi-Fi, more about all sorts of technical aspects of 802.11, as well as a great place to find friends and colleagues who share the same passions as you do.

First Steps – Getting Started

The first thing you need to do is setup an account at http://www.twitter.com – click on SignUp. You’ll be prompted for a Username. You can use a ‘handle’, or I chose to just use a unique version of my name. My username is KeithRParsons. In the Twitter-World you’d find me at @KeithRParsons.

Note: To say this out loud, you’d say “At Keith R. Parsons” – and the link on the Twitter site would be http://twitter.com/#!/KeithRParsons.

You can also add a ‘TagLine’ to your account so people can learn a bit about you. Including any links you might want to add to your personal or business web address. Be descriptive, yet concise. People will also learn about your likes and dislikes, hobbies and interests through your on-going tweets.

Next Up – Stop Using the Twitter Webpage

There are many Twitter clients – even the worst of them is better than the Twitter website. There are Twitter clients available for any OS, Windows, Mac OS X, iOS or Android.  Even official Twitter apps on most platforms. I personally use the Twitter app on Mac OS X, and one called Osfoora on my iOS devices.  Find one you are comfortable with, but in the beginning you could just go with the free Twitter apps.

Start Following People

Your “Twitter Stream” will be pretty much vacant until you start to follow people. Who to follow you might ask?  Well many great people in the Wireless LAN industry are already active in posting.

If you want to follow people involved in the Wireless Networking or WLAN fields, you can check out this list with descriptions of each at http://wlanpros.com/follow.

You could also use the ‘Search’ feature in your Twitter client, looking for the Hash Tag of #WirelessWednesday – you’ll find lots more like-minded folks to start interacting with. Feel free to branch out and start following others, family members, friends, etc.  And share your Twitter handle with your own community.

Get Involved

Now that you’ve started following some folks in our industry, it’s time to get involved. Engage in conversations. Don’t just listen – but actively ask people questions or ask for help in a given situation. Remember, you only have 140 characters. You you’ll have to work on your editing skills.  When you engage with others, people will notice, and start following you back.

Don’t just listen – but actively HELP others online. In this Twitter community, nothing is valued more than received prompt and timely help. If you read a question, and even think you know the answer. Get involved and take that chance and post your answer.

If you’re watching someone’s posts, and you like them. Respond with comments. (OK, if you don’t like their posts you can respond as well, just be careful as its easy to mis-construe comments that are only 140 characters)

Learn the Lingo

Twitter has some terms and techniques that might take a bit to understand. Lets go over some of the basics here.

Using URL Shorteners

Some longer URL’s would easily use up all 140 characters. You can use your own URL shorteners like bit.ly or the like. Or if you just put the HTML Link at the end of your message, Twitter will automatically shorten the link for you.

Using the @ Sign

If you start your message with an @ sign, the message will only go to the intended recipient, AND all those folks who follow both of you. But it won’t be sent to those who only follow one or the other in the conversation. Remember, if you lead with the @ sign, remember it will not be going to your entire following. You might want to edit the message to move the @ sign out of the first position if you want all to see the message.

This is a great way to start a conversation with someone. Just sent a message with their handle in the front.

What about that funny # character?

If you put a # in front of a word, Twitter will turn it into a link. This is called a “HashTag”. Please don’t over-use hashtags – a little is fine, but too much is just too much.

Direct Messages

If someone follows you, you can send them a Direct Message that no one else should see.  This is more like an IM message. Most Twitter apps have a single button or drop down choice to DM someone. Using DM is a way to carry on a more private conversation.

What are all these RT’s for?

Using a “ReTweet” is a way to take someone else’s Twitter message and “Re-Tweet” it to your followers. There is a built-in Twitter version that doesn’t allow editing – it merely forwards this message on with a tag showing that you sent it.

If you want to ReTweet and edit, be sure to give credit where you received it. Then add any comments of your own below.

Final Thoughts

Of all the tips and techniques listed below there are only two that really matter. First – get your own Twitter account setup. This should take mere minutes. Second – Get Engaged! Follow those with the same passions, and engage in conversations and responses. You’ll soon be Tweeting with the best of them!

I look forward to seeing your engagement on twitter!

In my career focusing on Wireless LAN’s for the last decade, I’ve found three fundamental differences between folks working in this industry.

Experience, Understanding of 802.11, and a background in non-Wi-Fi networking.

Let’s look at each of these.

First – I’ve met lots of folks who have an incredible amount of experience doing Wireless LANs… but were missing the other two facets. These are folks who perhaps started in this industry as a WISP or a builder of Hot Spots. They have installed hundreds of Access Points. Their first reaction when there might be a problem is to add more power, add more access points, or upgrade the CPE (Customer Premise Equipment). For these type, it’s all about the doing – they seem to move fast, and always have tools ready to go in the back of their truck.

This first type reminds me of the medical community of 100 years ago. The doctors at the time learned through experience what techniques worked. And for the folks at the time, they were the only alternative.

The second group are those who really understand 802.11. The experienced folks might look upon these as merely academics. These folks might have passed their CWTS, CWNA, CWSP, etc. and really have an understanding of how the 802.11 protocol works. They might also have learned about Spectrum Analysis, and can describe exactly how the SpecAn chipset works. In the ‘old days’ we might have called these folks “Paper-CWNAs” – because they had the certificate, and knowledge, but not an understanding of how things really work in the real world.

To stick with the medical analogy – these are MRI Techs – they can use tests and measurements to know EXACTLY what is going on inside the body – but don’t really know how to solve it.

The third group are those who come to WiFi via the Routing & Switching world. They have a great deal of knowledge and experience with TCP/IP, IP Subnetting, routing protocols, and can explain how Spanning Tree helps in their networks. These folks are mostly from the Cisco camp.

The downside is they come at the Wireless world with ONLY networking experience. They see Wi-Fi as just an extension to their Cisco network. When asked about their workflow, you hear things like, “I followed the design WLC told me to”, or “WLC this”, or “WLC that” – their entire understanding of Wi-Fi comes from their Cisco portal to Wi-Fi, NOT from actually understanding the 802.11 protocol.

These Cisco folks are like the guy with a Hammer, who seems to think all the world is a Nail.

The best solution would be to have parts of all these people rolled into one. The experience from the guy who’s been in the trenches, coupled with the understanding of the rest of the network from the routing and switching perspective, all wrapped up with a deep-level understanding of how the 802.11 protocol works.

It’s only when all three of these come together that you get a true Wireless LAN Professional who can design, install, and troubleshoot Wi-Fi networks efficiently and accurately.

We want to see a doctor that understands the WHY of the human body, as well has WHAT to do to fix the problem. (and *not* use a hammer…)

Yes, I know this is only one man’s opinion… but I’ve had too many years of dealing with each of these one-sided personalities.

So if you have lots of experience and yet really don’t understand the 802.11 packet flows, then take a CWAP course and learn to get down and dirty with the packets.

If you come from a Cisco (or other vendor) background with a strong set of Routing and Switching fundamentals… you too need to get into the 802.11 protocol directly. Don’t only rely on merely what your controller is telling you.

If you just happen to be one who has the academic understanding of 802.11, but don’t have any experience… get some. And for heaven’s sake get out there in the R&S world by getting a Cisco CCNA so you can learn about the rest of the network.

By the way, EVERYONE in the Wireless LAN community needs to at a minimum have a CWNA.  How can you work day-in and day-out with Wi-Fi and not be able to pass the CWNA? And if you can’t… they this is a reminder that you need to study and prepare so you can.

A CWNA from the CWNP program is the ante to play in this game!

Keith R. Parsons

keith@inpnet.org

http://Twitter.com/KeithRParsons

This is not some ‘Gartner Magic Quadrant’ type thing. No hard data, like from a Dell’Oro Group report. This is just my personal opinion of where these fall. Not a ranking by quality, or by technology… just a ‘gut feel’ from what I see out in the marketplace. They are just random inside the Tiers. I was not about to try and rank these within tiers… that would take more research and numbers… then this wouldn’t be a ‘gut feel’ but measured.

I would love to hear what you think. Did I miss any major vendor? Any of these placed in the wrong Tier?

Tier One

• Cisco
• Aruba
• Motorola

Tier Two

• Ruckus
• Aerohive
• Meraki
• Ubiquiti
• Hewlett Packard
• Xirrus
• D-Link
• Meru
• Enterasys/Siemens
• Trapeze

Tier Three

• Senao/Engenius
• Mikrotik
• Bluesocket
• 3Com
• LANCOM
• Extricom
• Proxim Wireless
• Belkin
• Linksys
• Netgear
• Fon
• SMC
• RealTek
• TrendNet
• ZyXEL

There are other Vendors who work in more Niche space like FireTide and Belair that I haven’t added to any of these tiers. Or those like Extreme that just OEM someone else’s product lines.

This is purely one man’s opinion… what are your opinions? Who should be moved between tiers, who should be added or removed? What WLAN vendors do you see in your space?

The Wireless Mesh Cost vs Throughput Spreadsheet.

The “Magic” in magic is really just a combination of illusion and mis-direction.  And yet we are entertained by being convinced we’ve seen something that breaks known physical laws.

We know the woman really isn’t being sawn in half, yet we don’t mind suspending reality for a couple of minutes while we try and figure out how the magician is doing his magic.

In the world of Wireless Mesh, sometimes WLAN professionals get too caught up in the mis-direction and illusion of getting something for nothing that we forget all about the laws of physics that determine connections and throughput and watch as our customers suspend reality hoping to get something for nothing, and not paying any penalties.

In reality, there is nothing “magic” about Wireless Mesh. It follows known laws concerning RF propagation, packet transfers, and network packet protocols.

I believe that Wireless Mesh does have it’s place in WLAN Design… but many people, in their quest to save a bit of money end up ruining their Wi-Fi network by employing mesh incorrectly.

To emphasize this point, I’ve developed an Excel Spreadsheet and made it available to download. (Link to Mesh Analysis Spreadsheet) – this spreadsheet, like all good spreadsheets, pulls the variables out where you can see them. All the fields colored in Green are the input points for the algorithms. You, as a WLAN designer can choose your own amounts for these.

Here are the variables you can enter to drive the equations in the Spreadsheet:

• Expected net TCP data rate on the 2.4GHz Access Frequency
  • I started using a value of 25Mbs to reflect a network where the bulk of the client devices are still 802.11g
• Expected net TCP data rate on the 5GHz Mesh Frequency
• This is estimated at a value consistent with an 802.11n connection
• Remember – the Mesh AP’s must be within range to have great SNR to maintain this data throughput!
• Number of Clients per 2.4GHz Access Point
• Cost of a wired Ethernet Backhaul connection
• Including Cat 5e cabling, installation, and cost for a switch port
• Sample Size of the Mesh Network
• number of Access Points to provide coverage for clients, as well as enough Mesh AP’s to maintain high throughput speeds between 5GHz Mesh RF connections.
• Average Loss in Percentage per additional Hop.
  • I’ve started with the minimum loss of 50%, in actuality there could be 10% to 15% more loss because of overhead and other issues.

Remember, you are the one to make these assumptions. This is not something that I’m making up – you put in your actual costs, size of system, assumptions on data throughput and number of clients per access point.

You can use this spreadsheet to work with your customers/clients to help them better understand the value and costs of providing Wireless Mesh versus other alternatives like Ethernet cable or a dedicated Wireless Bridge.

As an aside, I like to keep these in order both in my mind, as well as in the mind of my customers. Order of AP backhaul desired:

• Fiber
• Copper
• Dedicated Wireless Bridge
• One-Hop Wireless Mesh
• and way down here in the very last position
• a Multi-Hop Wireless Mesh

Also remember the first hop is ‘free’ – only kind of – since there isn’t the requisite 50% loss on this first hop. The receiving Mesh AP doesn’t need to re-transmit the packet on the 5GHz channel. The client packet comes into AP #1 on 2.4GHz, AP #1 then re-transmits the packet on 5GHz, then AP #2 receives the packet and places it directly on it’s Ethernet port.

But for subsequent Mesh Hops, AP #2 would have to re-transmit the packet on the same 5GHz channel it came in on… thus the 50% drop (Plus additional loses due to overhead issues) Each subsequent hop also results in this drastic degradation of data throughput.

Here are some graphical examples of this process of going to multiple hops. The horizontal access is number of Mesh AP’s – one more than the Mesh Hop (two meshed AP’s equals one Mesh Hop).

Note the gradual reduction in total cost as you add more Mesh Hops. It is true that adding Mesh rather than Ethernet will save you money, but only on the installation costs, not the actual cost of the Access Point.  But also note the drastic drop in throughput as you add more hops.

In this graph we can see as the average cost per installed AP drops (savings from the Ethernet cabling costs as you go with more and more Mesh Hops) the actual cost per kilobyte for each end user skyrockets. This is a function of more and more client devices sharing less and less actual Ethernet backhaul.

In this final graph we’ll focus on comparing the savings in percentage of lowered backhaul costs, compared with the loss of throughput. The “Sweet Spot” is at two Mesh AP’s or one Mesh Hop. Each additional Mesh Hop barely adds much in the way of cost savings, but instead has a huge drop in throughput.

Learn from the experience of others, and don’t get caught with a Wireless Mesh system that doesn’t provide for the requirements of your client devices.

Wireless Mesh isn’t “Magic” – it’s merely an illusion of cost savings – you still can’t break the laws of physics.

(a note that I’m not talking about Strix or Firetide Wireless mesh so hold your comments on those vendor’s proprietary solutions)

When looking at collected data, sometimes it seems to be quite random in nature. Looking at this random data, folks can make mistakes in analysis. One method we use to help ‘clean up’ this random data is to first sort the collected data from high to low, and graph according to percentage. This allows us to see graphically the differences between data sets.

As an example, I’ve put together the following sample data sets. Each has the exact same Maximum, Minimum and Average… but obviously, much different results. This is the value of this sorting method, it allows one to quickly see differences in data.

Seemingly Random Data

The first is a graph showing the two sets of data, fairly random looking. Both look like they are quite similar in nature, both inconsistent, and with a fairly same average.

Consistent vs Inconsistent Data

But when you take this same information and sort it first, you can see distinct differences in the resulting graphs. One set of data is much more consistent than the other. Even though they both have the same averages.

We’d like to see very flat lines, showing customer experiences to be fairly consistent across the board. The higher the lines the higher the client’s throughput results.

A line with it’s curve toward the bottom left represents a fairly low consistent result. A diagonal line represents high variability – more inconsistency. A line with the curve in the upper right represents consistently higher results.

Another way to use these ‘sorted’ graphs is to look at the 50% line – this represents the ‘average’ someone would achieve. The 80% line on the bottom represents that 80% of all collected data meets or exceeds this number.

This is a good telltale sign for following the 80/20 rule. Don’t waste too much time and money trying to fix the last 20% – put the bulk of your resources towards getting the 80% to be as consistent (flat) as possible.

Many decades ago I lived in Taiwan for a couple of years and learned Mandarin Chinese. Of all the tens of thousands of possible Chinese characters, there are only some 400 or so different sounds in the language. So many of the same characters (words) end up having the exact same sound. To counteract this obvious chance for confusion, sometimes Chinese people write out an imaginary copy of the character in question on the palm of their hand. A bit awkward, but it helps to convey which character goes with which sound.

In the English language, we too have difficulties at times with words having the same sound, but entirely different meanings. Some even represent a noun, and a verb with the exact same sound. For example, take the word Shift.

• Shift – to change gears on a car
• Shift – a type of woman’s apparel
• Shift – a time period for work
• Shift – what a Defense does in American Football
• Shift – an improvised knife used as a weapon

Thus we need context around the word to help us determine which version we are referring to.

As another example – the word Braces:

“You wouldn’t want to confuse the Braces holding up Larry King’s pants, with the Braces straightening his teeth, with the guest who Braces for the next question.”

In our world of Wireless LANs we too have to be careful in the use of various terms and words that can have different possible meanings.

We banter about the term ‘Spectrum Analyzer’ but which version might we be referring to:

• A $30,000 Spectrum Analyzer used in electronics labs?
• A $4,000 Cognio Spectrum Analyzer with custom ASICs?
• A $2,000 AirMagnet Spectrum Analyzer with software to share with WiFi NIC data?
• A $400 MetaGeek Spectrum Analyzer?
• An Atheros chipset with WiFi mode turned off and listening as a Spectrum Analyzer?
• Or finally what Xirrus calls a Spectrum Analyzer – but is just WiFi data in tabular format?

All are referred to as a Spectrum Analyzer – but they all have far different resolutions, and capabilities. Not that the most expensive is best – you’ll need to use the one that can show you the raw (non-Modulated) RF at the resolution you need to solve your current problem.

Set SoapBox = ON

Xirrus – just calling something a Spectrum Analyzer doesn’t make it one. No more than calling me a Marathon Runner makes me one. (I have ‘run’ (managed) the electronic timers at a Marathon – that doesn’t mean I actually competed) If your device cannot ‘see’ raw non-modulated RF – don’t call it something it isn’t. It might fool your customers – but not anyone who actually knows what a Spectrum Analyzer is!

Set SoapBox = OFF

Other words we use in the pursuit of our Wireless LAN systems that can be confusing include the word Interference.

We have:

• Raw RF Interference – non-802.11 modulated
• Co-Channel Interference – 802.11 packets on the same frequency
• Adjacent Channel Interference – 802.11 packets on nearby frequencies
• Interference because AP’s and Clients are sharing the same frequency with all neighboring devices on the same channel. (Like a hub has interference from all connected devices)

Each of these effects on our data throughput differently, and each need different tools to help troubleshoot and solve the “Interference”.

Or how about the simple term Noise that gets thrown around all the time. Which version of Noise are you referring to:

• Thermal Noise?
• Non-802.11 Modulated RF signals?
• 801.11 RF on the same channel?
• 802.11 RF on nearby channels?
• Ambient RF noise floor?
• Broken Packets on the same frequency?

Which of these above is what you are thinking of for the ‘N’ in SNR? Which version of “Noise” is used in your Wi-Fi NIC?

Spectrum Analyzers can tell some of these, a Wi-Fi NIC that is in promiscuous mode can see others. Knowing when to use which tool is very important.

In conclusion – remember just like the words Shift and Braces – we need to be very precise in the use of confusing Wireless LAN terms.  It will help clear up any confusion if you can be very precise when communicating terms like Spectrum Analyzer, Interference, and Noise.

Jared Griffith
Cinergy Wi-Fi, Inc
845 West 1025 South
Brigham City, Utah 84302
Office 877-782-5879
Mobile 801-808-7720
Fax 866-861-2133
Jared.Griffith@cinergywifi.com

http://cinergywifi.com

http://twitter.com/cinergywifi

Mobile Surveys Made Easy

This week is Part 1 – Fundamentals.

In the attached PDF white paper we’ll cover the basics and vocabulary needed to get started with Spectrum Analysis. Including talking a bit on how regular WiFi NIC’s operate. We need to know what spectrum analysis is NOT as well as what it is.

In subsequent weeks we’ll continue talking about basics of Spectrum Analysis and then how to intepret the results of using a SpecAn.

In the final week, I’ll talk about the various options available from $50 to $20,000. And the costs and benefits of choosing your Spectrum Analysis tools wisely.

I’m no longer teaching WLAN technologies full-time, I’ve taken a position with Ruckus Wireless to head up the professional services group, so I thought it would be appropriate to share these concepts and slides freely to the Wireless LAN Professionals community.

Enjoy!

Keith Parsons

Comments and questions are always welcome.

Enjoy ‘Perfing’ you network.

For those of you with AirMagnet WiFi Analyzer and/or AirMagnet SurveyPro software – you can also use the IPerf service within those tools. Doing an IPerf site survey is a great way to PROVE throughput over your Wireless LAN.

How to Guide on JPerf and IPerf

In the past year we’ve had the following successes:

• A total of 41 Podcast Episodes
• A total of 42,239 downloads of those episodes
• Slightly more than 1,000 downloads per episode
• The most popular episode had over 3,100 downloads
• The least popular episode had only 500 downloads
• 60% of the downloads are from the US
• With the other leading countries (in order): China, Canada, UK, Australia, German, India, New Zealand
• People have downloaded the podcast to over 100 countries
• The Wireless LAN Professionals website gets an average of 100 hits per day normally, but bumps up to an average of 200 on Wednesdays (the day the Podcasts are released)
• The WLP website has received 65,000 hits his year and over 20,000 downloads of white papers
• My twitter account http://twitter.com/keithrparsons currently has 943 followers and over 5,000 posts

I am posting these statistics for two reasons. The first is to give me some incentive to get back up on that horse and start regular weekly podcasts again. I’ve been a bit lax lately, and I needed some incentive to get back in the groove of weekly podcasting. Realizing there is a fairly decent sized audience will do that for a guy.

The second reason, and probably more important to the readers of this blog. You have a community!

There is a thriving community of people who are interested in the career choice of being a Wireless LAN Professional. Well over 1,000 people that I can track put themselves in this category. So get involved! Follow along on the twitter streams, follow the other like-minded individual’s fantastic blogs, post comments and perhaps even start your own blogs on the subject. (see the website’s resources tab for more places to get involved)

I’m a firm believer that:

“Knowledge is like manure, if you spread it around, it will help things to grow. If you try to hold it yourself, you’ll just start to stink.“

So please get involved in this community. Start following others on twitter, share your information, post your posts, and just get involved.

Keith Parsons – February 2nd, 2011

Years ago, a friend of mine, Kimberly Graves and I had been teaching both CWSP and CEH courses. At the end of those courses, our students would ask to see our ‘instructor kit’. They wanted to have the bits that we used in class to show off Wireless Hacking.

Kimberly was the author to the Certified Ethical Hacker study guide, and I helped with the technical edits on that book. I was also a Certified Hacking Forensic Investigator and Licensed Penetration Tester trainer for EC Council at the time.

So to react to the market, we developed a Wireless Hacking Course… but couldn’t call it that – since some companies and government agencies wouldn’t fund training with the word ‘Hacking’ in the title.

So we called it “Wireless LAN Security Assessment Toolkit” – and it was a course than not only taught wireless hacking, but also came with all the parts one might have needed. Spectrum Analyzers, 5 WLAN NICs, access points, hand-held client devices, and all the software pre-configured, and finally, even a laptop to run it all on.

This was a wildly successful class in its time. 

Both Kimberly and I have moved on and now both work for vendors, Kimberly does Course Development and Training for Aruba, and I am now doing Expert Services for Ruckus.

A couple of weeks ago, I was asked if I had any materials on the flow of Wireless Penetration Testing…

So we thought it might be a good idea to take the materials we produced for the WLSAT course and release them to the public. We’re not releasing any copyrights… just allowing folks on the Wireless LAN Professionals website to download and use them for personal use.

Below is PDFs of the printed student materials included in the Wireless LAN Security Assessment Toolkit course. Yes, these are a couple of years out of date… but many of the concepts and techniques used are still valid today.

You can check out the old marketing web page with the details on the old course. We’ve included PDFs from each of the chapters, so you can download them one at a time if you’d like.

Enjoy!

Here are the files for your perusal:

00 Student Kit and Classroom Setup.v7

01 wireless packet captures and conection analysis review.v7

02 Lab 2 Discovering, Locating, and Accessing WiFi Networks.v7

03 Sniffing and Capturing Data.v7

04 Encryption and Authentication Mechanisms.v7

05 Rogue Access Points and Client Hijacking.v7

06 Wireless Denial of Service Attacks.v6

07 Using a Wireless Instrusion.v7

08 Creative Advanced Attacks.v7

09 8oh2 custom linux script.v7

Appendix – Linux WLAN NIC Command Review

Appendix C – Linux Flash Cards v1.4.1

LinuxQuickReferenceGuide-v1.6.5

Wireless Penetration Testing Flowchart

]]> http://wirelesslanprofessionals.com/wireless-lan-rf-design-fundamentals-white-paper/feed/ 1 http://wirelesslanprofessionals.com/wlw038a-whats-in-my-wlan-toolkit-case-video/ http://wirelesslanprofessionals.com/wlw038a-whats-in-my-wlan-toolkit-case-video/#comments Fri, 26 Nov 2010 20:40:51 +0000 Keith R Parsons http://wirelesslanprofessionals.com/?p=1859 Here’s a video I put together that shows the equipment I take on consulting gigs. It might give you some ideas of things you might want to add to your holiday shopping lists.

Keith

What’s in My WLAN Toolkit Case

I thought perhaps with this being the holiday season, and people thinking of their gift lists… I ought to have an episode dedicated to the various WLAN hardware and software tools you might want to have in your own personal kit.

I tried making an audio podcast out of this list… but failed to adequately describe all the items with just my voice… So this week’s audio podcast will be turned into a Video Podcast. But, it will take a bit more time to edit the video clips into something presentable.

In the mean time, I’ve included a list of the equipment and software I carry. Obviously I don’t carry all of this for every type of gig. For pre-deployment work there is one set, for post-deployment verification surveys a different set. For different training classes, different sets depending on needs. And when doing interviews and on-site work for the Podcast an even different setup.

Please go through these lists and let me know if there are any tools you’ve found useful in your Wireless LAN Professional work that I should include. Please e-mail your updates/changes/answers to keith at wlanpros.com.

Thanks – and I’ll send out a Twitter message when the Video Version of this episode is ready to download.

The *-asterisk denotes my personal favorites and what I use most of the time.

Hardware

Computer

• Windows XP/Vista/*Window 7  –  Laptop/Netbook/*Tablet
• *Macintosh OS X/VM/*Parallels/*Bootcamp  –  *MacBookPro, *MacBookAir
• Smartphone  –  *iPhone, Android, BlackBerry

Accessories

• *Fluke AirCheck
• *GPS
• *Spectrum Analyzers
• WiFi NICs – both PCMCIA & USB
• Jammers
• *USB to Serial Converters
• USB Hubs
• Cases – I favor Pelican Cases

Miscellaneous Supporting Software & Security Software

• *MapPoint, *GoogleEarth, *Visio, *Office Tools
• Senao/Prism – Queensland Attack – WiFi Jamming
• *NirSoft  – WirelessKeyView – WEP & WPA PSK Hacking
• *Immunity – SILICAU – Penetration Testing
• *Franson – GPS Gate

Software

WiFi Analysis Software

• *AirMagnet    WiFi Analyzer Pro
• *AirMagnet    VoFi Analyzer
• WildPackets    Omnipeek
• *CACE Tech    Wireshark
• CACE Tech      WiFi Pilot
• Tamosoft        Commview for WiFi
• AirDefense     Personal

WiFi Site Survey

• *AirMagnet    SurveyPro
• Ekahau           Site Survey
• Tamosoft        Tamograph
• Visiwave         Survey
• Veriwave        Wave Deploy

WiFi Pre-Deployment Design Tools

• *AirMagnet    Planner
• Motorola        LANPlanner
• Ekahau           Survey

WiFi Scanners

• Kismet             Kismet
• NetStumbler  NetStumbler
• Xirrus              WiFi Inspector
• *MetaGeek     inSSIDer
• PassMark        WirelessMon
• *NirSoft          WirelessNetView
• *Koingo           AirRadar (Mac OS X)
• iStumbler        iStumbler (Mac OS X)
• WLAN Book    WiFi Scanner (Mac OS X)

Spectrum Analyzers

• Metageek       Chanalyzer (WiSpy family)
• *Metageek     Chanalyzer Pro (WiSpy family)
• Eakiu               Eakiu (WiSpy for OS X)
• *AirMagnet    Spectrum XT – USB – Bandspeed
• *Cognio          Spectrum Expert – PCMCIA (Cisco, AirMagnet, others)
• Ubiquiti          AirView
• AirMagnet      AirMedic – Intel 5×00 series WLAN NIC
• Nuts About Nets        AirSleuthPro
• Nuts About Nets        WiFi Eagle

2.4GHz and 5GHz RF Interfering Devices

• *Nuts About Nets      AirHorn Jammer
• *Nuts About Nets      AirHorn Dual-Band Jammer
• Portable Phones        2.4GHz Narrow-band and Frequency Hopping
• Portable Phones       5GHz Narrow-band and Frequency Hopping
• *Wireless Cameras – Jamming
• *Narrow-Band Jammer
• *Wide-Band Jammer
• *Bluetooth Devices – Discovery & Piconet
• *Headset, mouse, keyboard
• *2.4GHz Wireless Mice
• WiFi Video Camera – just as a client
• Old 802.11 Frequency Hopping AP & Client
• Microwave Oven – good and bad
• Nintendo DS (WiFi Client)
• Xbox 360 Game Controller

We’d love to have you subscribe to our RSS feed – just click the button in the upper right corner of the web page. Until next week, thanks for listening!

If you have any feedback on the show – please drop an e-mail to feedback@WirelessLANProfessionals.com.

Subscribe To The Wireless LAN Weekly Podcast:

Hopefully this will be resolved before next week’s scheduled show.

In the meantime, here are a couple of white papers written by Keith Parsons all in one place for easy access.

Again, our apologies. Looking forward to regularly scheduled Wireless LAN Weekly Podcasts in the future.

Keith

Learning Wireless LAN Technologies

Quick & Dirty 802.11n Design

WLAN = Counterintuitive

Want, Don’t Want, Don’t Care – Meeting Design Specs

Using The Right Tool for the Job

Seven Rules for Accurate Site Surveys

The Fallacy of Channel Overlap

False God of dB

How to Cheat on a Survey

Designing for Voice

Thanks for listening.

We’d love to have you subscribe to our RSS feed – just click the button in the upper right corner of the web page. Until next week, thanks for listening!

If you have any feedback on the show – please drop an e-mail to feedback@WirelessLANProfessionals.com.

Subscribe To The Wireless LAN Weekly Podcast:

You’ve heard things about this ‘social media’ thing, and wondered why everyone is talking about it. You might even have a Facebook page. But that’s just for sharing personal information about what you are up to with your friends and family. You also might be forward thinking a bit about your career and have already started a LinkedIn page, and shared your personal information and started to build your professional network.

Good for you, you’ve started down the path of adding some social media into your life. See, it’s really not all that bad.

Now on to the really powerful one called Twitter.  I know, you’ve heard people talk about twitter, heard these funny new words like “tweet” and “tweeps”, and worse of all you’ve heard all people talk about is what they ate for lunch.

I too was in your same place a while ago. Looking back, my first sign up with Twitter was over two and a half years ago, right after it started. But I was turned off by the service because of a couple of issues. First, I really didn’t like going to the Twitter web page to interact, and someone suggested I setup my cell phone to receive all my ‘tweets’ via SMS texts. That lasted about 20 minute or so of a frustrating endless vibrate going on. Second, I didn’t know anyone personally or professionally that used this new service.

Fast forward to spring of last year. Based on a very simple suggestion, I learned to access Twitter, not via website, or cell phone, but to use a Twitter Client. Wow! Everything changed overnight when I could access a ‘twitter stream’ and control the flow and content of the Twitter feed. It was a whole new experience. It made the process much easier and more manageable.

Then out of the blue, a new Twitter ‘friend’ (someone I’ve never met in person, who lives in a different country, but shares some of the same passions for Wireless LANs) – did be a huge favor and sent me a local European SIM card while I was on vacation with my family in Paris.  He basically over-nighted a loaded SIM for me, additionally gave me great suggestions on where to visit, and places to see. All because we had exchanged a few 140 character messages talking about our shared passion.

I found this Twitter thing could be valuable! I realized there are real people, who share many of my same goals and interests, willing to help and share their experiences with me, just for asking. And, that there were also people who could use my help as well.  A community of people, not tied together by some artificial reason because of where they live or work, but based on shared interests.

There is an entire world of Wireless LAN Professionals who are using Twitter on a regular basis. Of course for the Social bit, sharing what they are up to, where they are traveling, etc. But more importantly, they also share ideas and tips, as well as interesting URLs and articles about a shared passion. Twitter can also be a place to ask questions and get very timely answers.

It kind of reminds me of the good ‘ol days with BBS’s and Online Tech Support Forums where we’d go in the past to get that same timely, authoritative answers to pressing tech questions.

Give it a try, set yourself up an account on Twitter.com, its not only free, but very easy. Then try out one of the many Twitter clients available. I now use a funny-sounding client called Osfoora on my iPhone and iPad, and Tweetie on my MacBookPro. But there are many other clients available on all platforms, from Blackberry to Linux and everything in between.

To get you started on finding some folks who might share your interest in Wireless LANs, check out this list of folks that I follow at http://wlanpros.com/follow. You might also want to search for the “hashtag” (a Twitter method of tagging information) of #WirelessWednesday when people share other Twitter users addresses they personally recommend.

There are also many searchable, well-written tutorials on “How to use Twitter”.

I’d be pleased to have you follow me, and my status updates on Wireless LANs via my twitter feed – @KeithRParsons – http://Twitter.com/KeithRParsons

There won’t be an episode of Wireless LAN Weekly this week. (sorry)

I’m on a Cruise to Alaska with my wife, and though the brochures stated they had on-board Internet… they didn’t say that 4,000 people would be sharing a 1Mb pipe, And they didn’t share the costs… $.50 per minute online. The up-bound pipe is only 200k for the entire ship.

Thus, I won’t be able to upload the show this week.

But stay tuned, we’ll be back with new fresh content in next week’s Wireless LAN Weekly podcast.

Keith Parsons

Here are the links to those posts and some from George’s website.

http://wirelesslanprofessionals.com/rf-toolbox-iphone-app/
http://wirelesslanprofessionals.com/network-apps-for-iphone-revisited/
http://wlaniconoclast.blogspot.com/2009/04/wlan-professionals-portable-toolkit.html
http://www.my80211.com/product-reviews/2010/1/4/iphone-app-iphone-network-sniffer.html
http://www.my80211.com/home/2009/12/12/iphone-app-wifi-scanner-wififofum.html

I’ve had a day and a half or so to play with the new Apple iPad. (OK, I didn’t get much time to play with it today with all the family over for Easter dinner… they did enjoy themselves…)

Next week I’ll be doing more tests on the device using Protocol Analyzers and Spectrum Analyzers to get a bit more detail. But here goes for a ‘first pass’ on the device from a WiFi perspective.

Remember all those Wi-Fi apps that were removed from the iTunes store awhile back. Well, if you had downloaded/purchased those, and they are still in your personal iTunes, you are in luck. They work just fine on the new iPad. In fact, more than fine!

I was very impressed in whatever coding these developers used. The iPhone and iPod Touch only had 802.11b/g radios in the 2.4GHz range using 20MHz channels. But in my preliminary tests, those same Wi-Fi applications, when run on an iPad report with full dual-band 802.11n capabilities.

These older iPhone apps now report 40MHz wide channels (or 20MHz) in both the 2.4GHz and 5GHz range. Like some coders were either planning ahead, or the SDK automatically adapted with the advent of the iPad. Either way, I’m quite pleased!

Now these apps were not designed with the much larger screen of an iPad, yet they still work fine, just look either too small in the center of the iPad screen, or if you click the 2X button look too ‘chunky’ with blown up text with artifacts.

Not all iPhone apps worked on the iPad… but I’m amazed that most worked as well as they did in spite of the hardware platform and Wireless NICs being so different. Chock it up to a robust Apple SDK!

Below are some examples of the different Wi-Fi apps running on the iPad. More detailed packet-level analysis will be forthcoming.

On a side note. This little device is simply amazing. You WILL be using one in your future. From my 73-year-old mother, to 5-year-old great nephews, to all sorts of family in between. They all ‘Got It’ by just holding it, playing with the interface, and using it in their own way. Checking on blogs, updating Facebook, playing games, checking RSS Feeds, reading books, watching movies, looking at Comics, answering e-mails, and many many other tasks, the iPad just worked. Everyone was smiling and enjoying the experience.

For hard-core CLI-type folks, this isn’t anything you’d want… and people will have lots to say about what the iPad isn’t. But what it is, is… just great technology that works. Works the way people expect technology to work.

WiFi Analyzer - click to see 2X Artifacts

WiFi Analyzer - Graph

WiFiFoFum

WiFiFoFum Radar

WiFiGet Plus

WifiTrak

RF Toolbox Sample

]]> http://wirelesslanprofessionals.com/apple-ipad-and-wireless-lan-professionals/feed/ 4 http://wirelesslanprofessionals.com/getting-higher-quality-calls-using-skype/ http://wirelesslanprofessionals.com/getting-higher-quality-calls-using-skype/#comments Fri, 02 Apr 2010 13:03:46 +0000 Keith R Parsons http://wirelesslanprofessionals.com/?p=1331

• Try to be in as quiet of a room as possible.
• Use a Headset. Do NOT use the computer’s built-in Mic/Speakers
• Position the mic to be above/below your lip level (check for no breathing sounds from mouth or nose)
• Check in the Audio Preferences and set your mic and headphone levels to be in the green
  Not spiking to the Red, and not too quiet… just right!
• Shut down all other application while in Skype
• Connect to the Internet via Wired Ethernet if possible – Wireless if you can’t do wired. 5GHz 802.11a would be a better choice that 2.4GHz 802.11b or 802.11g
• You can configure Skype to show Advanced Settings to check for VoIP details
  • Roundtrip should be under 200ms
  • BM (Bandwidth) is best >5000
  • UDP Status (both) should be Good
  • CPU should be <25% – this really helps
  • Relays should be 0
  • If it is 4 or more, you are probably behind NAT
  • You might need to assign the Skype Port to pass thru via Router Settings
  • Packet Loss – Zero is best – but try to keep this as low as possible

I would love to hear what you think. Did I miss any major vendor? Any of these placed in the wrong Tier?

Tier One

• Cisco
• Aruba
• Motorola

Tier Two

• Meru
• HP
• Enterasys/Siemens
• Ruckus
• Aerohive
• Trapeze
• Xirrus
• Bluesocket
• 3Com
• LANCOM
• Extricom
• Proxim Wireless

Tier Three

• Senao/Engenius
• Ubiquiti
• D-Link
• Proxim
• Belkin
• Linksys
• Netgear
• Meraki
• Fon
• SMC
• RealTek
• TrendNet
• ZyXEL

4/9/2010 – Update

I think I need to re-visit this list based on a bunch of feedback. Folks would like to see them ‘ranked’ (no, not going to do it) and add a different category for Mesh/PtP/PtMP kind of stuff. I personally don’t have a lot of experience there. Anyone want to tackle the job?

1 : a salad plate of chopped meats, anchovies, eggs, and vegetables arranged in rows for contrast and dressed with a salad dressing
2 : a heterogeneous mixture : potpourri

IT Professional Apps on iPhone

If you are interested in iPhone/iPod Touch/iPad apps that would help as an IT Professional, specifically involved in Wireless Networks, check out a couple of blog posts I wrote on the subject with lists of available network support tools.

I think you’ll be surprised how useful this can be to an IT Professional.

http://wirelesslanprofessionals.com/rf-toolbox-iphone-app/
http://wirelesslanprofessionals.com/network-apps-for-iphone-revisited/
http://wlaniconoclast.blogspot.com/2009/04/wlan-professionals-portable-toolkit.html
http://www.my80211.com/product-reviews/2010/1/4/iphone-app-iphone-network-sniffer.html
http://www.my80211.com/home/2009/12/12/iphone-app-wifi-scanner-wififofum.html

Study Exam Objectives

Can we take Wlanman09′s words and tattoo them to all potential CWNA/CWSP/CWNE students?

There are many shortcuts to passing exams – brain dumps, practice tests, etc. But the best so far is as he suggested… study the Objectives.

The exam questions do NOT come from the Study Guides, or from the practice questions. But they *are* tied directly to Exam Objectives.

All of the support materials will also try to map to the exam objectives… but there is nothing to guarantee they will prepare you in all ways for the test. Be sure you UNDERSTAND the objectives thoroughly before attempting the exams.

CEH, LPT and CWSP

I’ve taught all three, CWSP, CEH, and the LPT (as well as the associated CHFI and other forensics classes)

The CEH is very very broad – I was the technical editor on Kimberly Graves latest CEH Study Guide (Sybex) and it covers all types of hacking. The accompanying resources that come with the authorized student kits are HUGE. Massive amounts of information are covered, and needed to pass this broad ranging exam. (Kimberly is also CWNE #2 and a great instructor if you can find a CEH class where she is instructing)

The Licensed Penetration Tester is more hands-on, and detailed oriented more on the actual processes of doing Penetration Testing. (CEH more conceptual) plus you have to pass a ‘background check’ to show you are ‘of good character’. If you want to do Pen Testing for a living, this might be for you.

There are many other Forensics type classes… more along the lines of tracking hackers after the fact.

If you are into the generic Security – look into CISSP and GIAC… but nothing out there is better for Wireless Security than the CWSP. By the way, the new CWSP study guide from Coleman, Westcott, Harkins and Jackman is a fantastic resource. But you’ll also have a pretty fun experience doing the classroom labs.

If you don’t have the travel budget for an live-in-person instructor-led CWSP course. Rick Murphy over at http://www.wirelesstrainingsolutions.com/cwsp-training-classes has a great remote setup where you still get to do all the labs as well as the lecture portions.

As a ‘side note’ you might want to think about all the reading that will be involved in any of these Certifications. Security is an in-depth detail oriented topic with many many facets to cover in short periods of time.

WLAN Spectrum Analysis Devices

In the Spectrum Analysis arena there are a couple of options as well.

The cheapest is the AirView2 from Ubiquiti – a small USB 2.4GHz spectrum analysis tool. Probably the least resolution available though. But it is very inexpensive.

The folks over at Nuts About Nets also have a couple of options in lower-cost SpecAn devices, but I’ve only used their ‘jammer’ tools called ‘AirHorn’.

Metageek has some fine individuals working there and they have an entire series of small USB spectrum analyzers, starting at only $100 for the 2.4i and moving up to their flagship DBx that does both 2.4GHz and 5GHz analysis.

There are also ‘bug’ type spec ans from the guys at Berkely Varitronics, little hand-held units (based on like pocket pc devices) that are fairly light-weight but still do detailed RF analysis. But not too user friendly in their reporting. You’ve got to know what you’re looking at.

AirMagnet/Fluke has just started shipping their own Spectrum XT product – a very high-end professional tool designed to supercede the Cognio version, but in an easy-to-use USB form factor. This one also integrates very well with you local WiFi card for integrated analysis.

The big gorilla in this marketplace is the Cognio Spectrum Analyzer, the company was purchased by Cisco awhile back, and you can still get these OEM branded through a variety of sources, Cisco, AirMagnet, Fluke, etc. I’ve spent many many hours using this tool and feel very comfortable finding just about any RF source… but it is the most expensive of the WLAN SpecAns.

Of course if you have even more money you can go with a full-blown SpecAn from the big boys but those are huge, expensive, but can ‘see’ a wide variety of frequencies.

There’s a quick review of the SpecAn marketplace as of today.

WLAN Packet Capture Tools

Omnipeek Personal is no longer available.

I like the AirMagnet WiFi Analyzer, but it does cost a bit of coin for a professional tool. This one shines for ease of use, speed, and robust analysis.

Omnipeek professional is also a good choice. Very good live decodes, and lots of analysis above the MAC layer.

When doing packet injection I use Commview for WiFi. Also ties nicely in with NetResident for seeing upper-layer decodes (like watching websites, emails, voice, etc. over the WLAN)

Of course you can always go with Wireshark with a CACE AirPcap solution. Or if you are so inclined you can go with the Linux version of Wireshark and not need the AirPcap. Check out one of the Backtrack CDs.

I’ve just received the latest from AirDefense, called AirDefense Personal and I’ll be giving it a run-through as well.

I carry all of these on my main laptop, they each have features that make them worth using.

For an upcoming book I’m working on, we’ll be using Wireshark/AirPcap as the main deliverable since the base software is available for free download.

WIDS/WIPS

I’m personally a bit partial to the AirMagnet Enterprise solution. I’ve done many consulting gig installs/configurations with this and have found it to be a very robust solution for WIPS. But in my opinion most people purchase such a solution with ‘security’ money, and it does a great job there. But the real ROI comes from the performance improvements it can find to help make your Wireless LAN more efficient.

I’ve also worked with AirDefense and AirTight and think they are also very good solutions.

In my opinion any of the ‘overlay’ WIPS solutions will always be a better solution than any of the ‘time-slice’ solutions the AP vendors try to sell. (read up on the Joanie Wexler WIPS series)

Cost wise an Overlay solution needs dedicated sensors, and a time-slice solution needs additional APs put into ‘monitor’ mode. For my money (and these both cost about the same) I’d go with a device that had been designed and dedicated to specifically doing one job well.

I know the AP Vendor sales folks would much rather sell you ‘spare’ Access Points… but dedicated sensors can do a far superior job of ‘watching’ your network.

You can also install an Overlay WIPS in a ‘no-wireless’ policy area where/when you have no Access Points in the area.

Just one man’s opinion,

WIDS/WIPS Capabilities

Now to answer the other part of Wilddev’s question.

Kimberly Graves, CWNE #2 and I developed a course awhile back on Wireless LAN Penetration Testing called WLSAT (Wireless LAN Security and Assessment Toolkit) where we taught folks how to use the latest in penetration testing (read HACKING) into wireless networks.

There are many many techniques. But you asked: “how well the can detect and prevent someone who knows wireless well from getting past them?”

Both the Overlay and Time-Slice models allow for the Detection of just about all forms of Wireless Attacks. They all use some sort of Denial of Service to do the ‘Prevention’ bit of a WIPS service. This in itself was designed to protect the client’s own network from unwanted wireless connections. But this also has an unintended consequence, it in itself perpetuates the Denial of Service for the clients’ employees who happened to be connected with the Rogue devices. Be sure your help desk knows the signs and symptoms that occur when your WIPS is in ‘protect’ mode.

Also be cognizant of the legal ramifications of having a system that can cause DoS attacks to your neighbors if implemented and configured incorrectly.

WIPS/WIDS systems can do a great job protecting your Wireless infrastructure, but from the hackers standpoint, wireless is only one of the access methods into your network. You’ll need a broad spectrum security solution, wireless is only a component in that system.

Learning to Read SpecAns

In response to a blog post by Ben Miller over at http://www.sniffwifi.com/2010/03/pleasant-wispy-surprise.html

Ben thought the WiSpy Spectrum Analyzer was something ‘less’ because it doesn’t include Device Identification. I like using all the Spectrum Analysis tools… but have found you as a ‘human’ have the best ‘pattern identification’ there is.

Though I teach folks how to use the Cognio Spectrum Expert (AirMagnet’s version) as well as AirMagnet’s own Spectrum XT, both of which have built-in identification. I try very hard to NOT use the built-in device identification.

Instead I teach how as a ‘human’ you can also beat the computer in identification, the ability to ‘see’ things/patterns in the FFT plots and Swept Spectograms. It takes more effort. More experimentation. And more time. But the results are better as well. Anyone can read the auto-identifier’s report that it sees a Bluetooth device. But as a ‘human’ with better recognition, you can see the pattern that can only belong to an iPhone or see the ‘signature’ of a Palm Pilot.

It’s kind of like learning to read sonograms or x-ray results. It takes lots of practice. But in the end, a ‘human’ will always be able to beat a computer in pattern identification. (Think of hearing your child’s cry at a noisy playground)

Student Study Lab Equipment

I’d strongly recommend working with at least ‘tier three’ type enterprise products. If you can get your hands on any Cisco or Aruba controllers and APs…that would be best for your career. But you can probably use the semi-enterprise stuff from Engenius or Ubiquiti stuff to get you the experience you need for the CWNA exam.

Anything from the ‘tier two’ enterprise vendors would be more than enough as well. (Ruckus, Aerohive, Trapeze, Meru, Motorola, HP, etc.)

Working on just SoHo type equipment won’t be enough. Most only support WPA I/II with PSK – and you should have experience with Radius if at all possible.

From the ‘old days’ of Novell CNEs – those who had their own lab setups at home were always prized over the ‘paper-CNE’ types when it came time to getting hired.

“Ripple Tank” Animations

I’ve used the program Eminem extensively to view wave forms to show Amplitude, Polarity, Frequency, etc.

But this Java Applet might be what you’re looking for.

http://www.falstad.com/mathphysics.html

Try both the 3D and 2D wave applets.

Begging for Comments and Suggestions

Comments or suggestions on these or other topics is always appreciated!

Let me know if you think any of these short blurbs justify longer blog posts or white papers. Thanks!

IEEE Handbook

802.11 Wireless Networks: The Definitive Guide, Second Edition

802.11 Wireless LAN Fundamentals

Cisco Enterprise Mobility 4 1 Design Guide

Cisco Wi-Fi Location-Based Services – Design and Deployment Considerations

Vocera IP Phone Deployment in Cisco Unified Wireless Network Infrastructure

Cisco Spectralink Phone Design and Deployment Guide

SpectraLink  “Deploying Netlink Wireless Telephones: Best Practices“:

CWNP Resources and Books
- CWTS Official Study Guide

- CWNA Official Study Guide

- CWSP Official Study Guide

- CWAP Official Study Guide

- CWNP_exam_terms.pdf

- CWNE Exam Objectives.pdf

Wi-Fi Alliance docs ( – membership required):
- WFA Certification Roadmap
- WFA WMM Power Save
- WFA WMM Support for Multimedia Applications
- WFA WMM_Specification_1-1

IEEE Standards (membership required):
- IEEE 802.11e-2005 (or later)
- IEEE 802.11h-2003 (or later)
- IEEE 802.11ma-d9.0 (or later)

CBT Nugget’s CWNE Video Certification Series:

This has been corrected and the corrected version is now available.

Thank you for your understanding.

In our craft of working on Wireless Networks… we need to have our own phrase to follow:

In many of the Wireless Networks I’ve worked with, the designers, installers, and folks who have to maintain the network get all focused on the Access Point side of the equation. Worrying about the APs are doing, is there adequate coverage, what the controller reports, etc.

But when was the last time you had to directly troubleshoot an AP?

No, we are always tracking down problems with the clients, yet we do our entire Wireless LAN designs with Access Points in mind.

I’m suggesting we start thinking more and more about the Client side of the equation. Thus, “What Would Clients Do” should become our watch words.

Here’s some examples of where to think from the Client’s perspective instead of from the Access Points:

Coverage Overlap – the Client wants to see a ‘primary’ AP and a ‘backup’ AP – they don’t care a bit about what the coverage looks like on a floorplan. Measure for Primary and Backup coverage in dB – not in percentage.

Channels – Clients will *always* move to the channel of the AP their algorithm chooses as ‘best’. Don’t worry about channels from a client side, make sure your AP’s channels keep co-channel interference as small as possible.

Collision Domains – from the Client’s perspective, all those APs and other clients that it can ‘see’ from wherever it is, it has to contend with, and wait for, ALL of those to access the frequency to send it’s own frames. Thus many times when the human clients complain about a ‘drop’ in their wireless, they are referring to the delay caused by a collision domain, NOT by a lack of RF coverage. Minimize Collision Domains by LOWERING POWER.

Coverage – we tend to want to have more and more power, but that’s NOT what Clients want to see. They need to have one strong signal, a backup signal, and then as little as possible. You can measure this by turning on your favorite tool of choice, and seeing how many APs you can see at what RSSI levels from any location. If you are troubleshooting a Client, and yet at that location you can see more than two strong APs, well you don’t have an RF coverage problem! You have too much coverage and that causes a collision domain, and all the bad things associated therein. Design for adequate coverage, not too much coverage.

Heat Maps – many vendor’s controllers will show you ‘heat maps’ — but this is from the Access Points perspective, the Clients are not included in the equations. If you want accurate heat maps, you must do a survey with a client, at a client height. AP to AP communications, though nice, are NOT sufficient to know what the clients will see. Survey regularly with a client, at client height, with regular traffic loads, to get accurate heat maps to really know what your coverage patterns look like.

Dropped Sessions – sometimes we opt to think when laptops somehow lost a connection, it was caused by a drop in wireless. Many times it isn’t a lack of signal, (see coverage above), but a dropped connection higher in the stack. If you were trying to diagnose a wired laptop who complained about a ‘dropped connection’, but when you arrive on scene the ‘link light’ is still glowing steady, would your first thought be the patch cable is somehow broken and merely replace the patch cable? Of course not. Yet many times our first ‘solution’ is to look down the stack to the MAC and PHY layers–only because we can easily see the ‘link light’ on wireless. If a clients is still associated to an Access Point, the problem is higher in the stack. Remember, association is to wireless what a link light is to wired.

I welcome your comments and suggestions on this and other Wireless topics.

Well in the example above, and from this graphic – it looks like Collision Domains are a only problem of a wired Ethernet system. But in addition, it is also very prevalent in Wireless Networks. Whenever devices, including Access Points as well as Client Stations, can ‘see’ each other on the same channel (with enough RSSI) they will be forced because of the protocol to wait for others on the same channel to stop transmitting before they can start their transmissions.

This process of a ‘Contention Window’ is a part of the 802.11 design specs.

As an example, here is a capture from the baggage claim area at a large airport. Note all the Access Points that are sharing the same channels. Adding more APs does not always add more capacity. Sometimes, when the APs can ‘see’ each other, they only add to the contention window and don’t ‘net’ any additional throughput.

In fact, many times this is the problem when clients are having ‘difficulties’ with their wireless connections!

This is easy to find. Just fire off your favorite tool that lets you see the access points, their channels, and their signal strengths. If from one location you can see more than two Access Points on the same channel with RSSI’s greater than -80dBm… then that channel has a ‘Collision Domain’. Plain and simple. Meaning when either AP talks, the other *can’t* talk–because it is waiting for the other to finish. (a definition of a Collision Domain)

Try it on your wireless networks and see what kind of Collision Domain’s you’ve designed into your network. What? You didn’t design in collision domains? Then why are there more APs showing up on the same channel at the same location? If you didn’t do it, then who did?

Many times folks who do ‘AP-on-a-stick’ site surveys and call them wireless network designs NEVER check this co-channel interference and you are left to deal with the results of having way too many devices sharing the limited capacity of a specific frequency!

Measure, Measure, and Measure your wireless network to *verify* not only where you have signal, but also where you have too much signal. (you measure your cable plant, why don’t you measure your wireless media?)

You also might want to check out my White Paper called ‘Want, Don’t Want, Don’t Care‘ and be able to define what your client stations use to determine those three levels.

As a side-note. My friend David Coleman, of CWNP, CWSP, and CWAP study guide fame, refers to this ‘Collision Domain’ as a ‘Contention Domain’… I agree with him.

Questions? Comments? Please leave your thoughts in the comments section below.

But many times their Anti-Virus ‘screams’ at the ‘Hacking Tools’ (like the ping-sweeper AngryIP) included in the set. Sometimes these student’s machines even delete files from my USB sticks and so the next student doesn’t get all the files.

Enter AirStash. I heard about this a while back and have been patiently waiting for an ‘official’ announcement. Well today it was official. And so I purchased one as soon as it was available.

This small device forms a little mobile ‘HotSpot’ and shares whatever is on the inserted SD card via Wi-Fi. Way cool.

It can work with your iPhone, Mac, or PC — to share media files, music, or data files — easily, simply, and without wires or plugging anything together.

I’ll give a full review as soon as mine arrives. waiting… waiting… waiting… when is that UPS guy going to arrive?

When I started with Twitter years ago, I was less than impressed. A bunch of people talke about what they ate for breakfast, and I only used the Twitter Website. Then later after someone suggested I start using a Twitter Client (Like Tweetdeck, HootSuite or Tweetie) – I finally found I really enjoyed the friendships and camaraderie found between folks with like-interests. The clients allow you to have much better control and access to your twitter feed.

You can even start using #hashtags and @replies to communicate and search for information pertaining to your own specific interests. (This isn’t going to be a tutorial on Twitter – just ‘Google’ it and you’ll find lots) Just understand – twitter can be much much more than status updates – it can be a place for knowledge, learning, entertainment, and friendship!

I’ve put a page together with the Twitter folks I follow (not all are Wi-Fi Folks – but most are)

The CWNP Program also has built some lists specifically for CWNTs, CWNEs, and WiFi Vendors.

If you’d like to be added to the Twitter Follow List - or have any suggestion, please send your information to feedback@wirelesslanprofessionals.com.

Feel free to peruse the older posts, there is some pretty good information contained therein.

To track down those older posts go here.

Any comments or suggestions would be greatly appreciated!

I’ve tried little speakers that attach to the side of your laptop, speakers that have their own internal batteries, those that recharge off of USB power, speakers with little ‘pop’ out bass enhancers, ball speakers, brick speakers, foil speakers… well you get the idea. I’ve even tried a fairly heavy little brick shaped speaker from k-box that made the entire desk into a large bass’y sound producer.

But I’ve finally found the ultimate speaker for me. Aaaaah. Speaker bliss.
It is small, charges from USB, connects to computer or iPhone, sounds good with movies, sounds good with both classical music, and has enough thump to not embarrass the Hip Hop sounds.

I’ve started to carry with me the TuneBug Vibe.

It’s not really inexpensive… but it does make up for the cost in the sound quality and workmanship. (It has a nice solid feel and heft to it, without feeling too heavy to carry with you) Though it is like the k-box in making sounds via some other conductor, the sound is far superior.

It works best on something a little lighter-weight than a desk. I’ve successfully used it just sitting on the wrist-rest of my laptop, or on my Dr. Dre Beats headphone case, or even on a small snack box. The sound is crisp, clear, and has enough bass to be just right. It even comes with a little box – just put it on the box and you have great sound. But I’ve found I an always find something in the hotel room to use as the resonance chamber.

I can strongly recommend this speaker to be included in your travel kit!

I’ve known Laura for many years, as well as worked with her on multiple projects and training tours. She is a fantastic trainer and author. You won’t go wrong by reading and learning from this book. There is quite a lot of detail in this book on many levels of network analysis and troubleshooting, including information important to Wireless LAN Professionals.

You’ll get 35% off by using discount code “998nws35“

I’ve pre-ordered my copy, get yours here

For more detailed information read the table of contents. (PDF)

These are the blogs that share things of value – so the purpose of this post is to salute those who spend un-told hours preparing and delivering great content for the rest of us to consume and use in our daily lives. My hats off to these dedicated bloggers. To a job well done!

I’ve picked a sampling of their posts to share and link back to. Please feel free to click through on these links for the specific posts… but also spend some time on their site to see all the other posts and items that are available.

Personally I *really* don’t like the sites that make me ‘register’ to see their stuff. I understand ‘Why’ they want my contact information, but I *will* come back if your content warrants it.

On to the list for this week – Go ahead and click to see the posts:

What are some of your favorite blog posts?

Leave comments with your suggestions.

I am totally open to your critique on this – please send feedback with your comments!

The discussion usually starts when the client already has a working Wireless Network, and is asking me to simply add voice to the existing Data Wi-Fi system.  They always make is sound so easy, “just add the voice thing”… but it isn’t easy at all.

Data networks and Voice networks have different design parameters. Different packet flows, and way different expectations with respect to coverage, continuity, etc.

Controllers and APs will use the ‘Automagic’ function… yeah, right…

In the ‘old days’ we designed networks for coverage – only spec was to get signal to the designed areas at a specific RSSI (dBm).  To verify the design, we could easily go out and walk around watching the signal strength and ‘prove’ we had a good wireless network.

No longer is mere coverage measured by RSSI (dBM) sufficient, you also have to meet ALL the other design constraints for Voice. By the way, these each might have different answers depending on the VoWiFi handset of choice.

After going through the following list with clients, they either push back hard asking why I’m asking them so many questions—they just want it to work without any work on their part.

Or, they get overwhelmed with all the details and think their Controllers and APs will use the ‘Automagic’ function and all will be well with the world.

Designing Wireless LANs to actually work… is WORK. Designing for Voice takes even more work. (and a lot more money!)

By the way, I haven’t even touched the client side of this equation, or the call manager, or RF interference… we’re just getting started folks!

Oh, and one more thing… all of these delays listed below are on top of VoIP network latency caused by Propagation Delays, Handling Delays, and Queuing Delays on the Wired Network. Fun, Fun, Fun!

To get a Wireless Network that actually works, be sure to design, measure, and verify the following Wireless LAN Specs:

First AP Coverage

• Usually something like −67dBm or better
• I describe this at the ‘want’ area

Second AP Coverage

• Perhaps −70dBm or better (Cisco phones want −67dBm)
• Some people call this ‘overlap’ but it’s not measured in percent of area, but in dBm for the ‘backup’ coverage
• You can’t measure the ‘overlap’ in percentage, but you can measure ‘backup coverage’ in dBm.

Co Channel Interference

• Above −67dBm and less than −85dBm on same channel equals Interference
• In my terms I describe this as the ‘Don’t Want’ area – less than −85 is the ‘Don’t Care’ zone
• By the way, this is the HARDEST to achieve, but when you don’t achieve it, you have large collision domains, where many clients and APs must ‘share’ the frequency, resulting in many additional problems

Client to AP Density

• Usually something like 10:1 or for some VoWiFi handsets 7:1
• (you actually need to do an Erlang analysis to find how many ‘average’ minutes of call per hour for this calculation)
• You need to be able to measure and verify there is appropriate number of APs for clients

Additional Density

• Areas where there might be an abnormally high concentration of devices
• (Auditoriums, around nursing stations, etc.)
• You need to be able to measure and verify there is appropriate number of APs for the clients IN that area

Data Throughput

• First would test for ‘gross’ data rate, like 1, 2, 5.5, 6, 11, 12, up to 54Mb/Sec
• More importantly, check for NET throughput with iPerf to meet design standards
• You can check data rates *to* the AP (wireless rates) by sending packets to the AP
• You can check data rates *through* the AP by placing the iPerf server directly behind the AP
• Or check data rates *through* the Network by placing iPerf server back near your core where your servers are

Jitter

• Less than 5 msec
• Variation of latency between packets
• Measure both upstream and downstream jitter during a two-way conversation call in progress

Latency

• Less than 50 msec – total end-to-end delay

Packet Loss

• VoIP really likes to see less than 1% packet loss
• Achieving a 1% packet loss is highly unlikely given the physics of Wi-Fi

AP Handoff

• Less than 50 msec
• This can be improved with a proprietary Distribution System (all APs enterprise-class from same vendor)
• Fast Secure Roaming can also help
• Try testing on an ‘Open’ SSID first, then test again with your Authentication system in place

Codec

• Use a Codec that has the highest potential MOS score
• Don’t try to use compressed Codecs, we have lots of bandwidth, it’s a quality issue with Wi-Fi

Roaming

• Data usually has a ‘Portability’ need for coverage
• Portability – loose session, but not IP upon roaming – Like sleeping your laptop as you move to another room
• Voice has a ‘Mobility’ need for coverage
• Mobility – can’t loose session at all during any roam

Authentication

• Open is the fastest for supporting Voice over Wi-Fi, but has no security
• WPA-PSK still requires a key exchange upon roaming
• WPA-Radius might require a full authentication cycle clear to Radius Server
• Some vendors support key caching or fast secure roaming

Coverage Areas

• Usually designs for Data include areas where laptops go (carpeted or vinyl floors)
• Voice designs also need Elevators, Stairwells, bathrooms, parking structures, etc.

Collision Domains

• You can’t change the Physics of Wi-Fi, it will always be a Shared Medium
• Design accordingly

Quality of Service

• Choose your Priority Queues appropriately; realize with Wi-Fi we don’t have an Absolute Priority
• Only a statistical advantage, Data WILL sometimes get in front of Voice traffic
• Make sure ALL your APs and Clients can support the QoS system you choose
• Put Voice and Data on separate frequencies to guarantee they don’t share the same medium

Error Rates

• Set parameters and design goals for Retry Rates and CRC rates on your Wireless Network
• Measure and be sure to verify before starting the Voice clients on the Wireless Network

Translation Delays

• 802.11 Wi-Fi to 802.3 Ethernet translation adds a slight delay

Transport Delays

• Lightweight APs have to send their frames back through Access and Distribution switches prior to reaching the Controller at the Core, then forward back through same process from Core back to Access layer devices

End to End QoS

• Check to see your QoS set at the client carries those priority bits clear through your network to the receiving client

Whew! – and those CMRs thought it was going to be easy to add voice to your Wi-Fi network.

Protection Mode

• When designing around a b/g mixed mode environment the Protection Mode adds overhead to every packet exchange
• Get rid of all 802.11b clients on your network, as well as within range of your network – if possible
• Set expectations accordingly if you must support mixed b/g networks—at least ½ data rate loss minimum plus additional packet overhead

Power Management

• Use the most efficient Power Mode supported by your clients and APs
• Some of the older versions were terribly inefficient, especially with respect to Voice packets

SSIDs & VLANs

• When configuring a unique SSID for Voice, remember adding a VLAN to Wi-Fi does NOT break up any broadcast domain, you are still in a collision domain and broadcast domain with all other devices on same frequency within hearing range

Oh, and did I also forget to mention all the issues of working with the new 802.11n header structures, new power management schemes, MSDU lack of Priority in the header, MPDU size delays, and Non-Greenfield protection delays, as well as overhead caused by DIFS, Preambles, Headers, SIFS, Preamble, ACK — plus the whole Contention Window Delays?

Oh, and did I also mention you need to have the correct tools and skills needed to test and VERIFY all these items?

Whew! – and those CMRs thought it was going to be easy to add voice to your Wi-Fi network.

I’ve worked with Wi-Fi analysis tools for many years now, from the old Compaq iPaq based devices, to the ‘Bug-named’ devices, and onto many laptop tools. So perhaps my experience is a little biased. But this cute little thing is amazingly fast and easy to use.

Without a single prompting from the Fluke Networks rep, I was able to start the device (wicked fast by the way) and start analyzing the local Wi-Fi environment, do some sample troubleshooting, and even do a ‘find’ on a Wi-Fi device.

The form factor of the device is easy to grasp, and the color screen very readable. But what amazed me most is the absolute speed of how fast it does it’s assigned tasks.

In no way was this device intimidating. I found the interfaces elegant, and very intuitive to use.

I’ll be doing an in-depth review of the Fluke Networks AirCheck device soon, but wanted to do a quick post to whet your appetite. You *will* be wanting one of these in your kit!

You can get the details on Fluke Networks Website.

There is a pretty good demo of the AirCheck here.

I wonder if those are ‘All Weather’ Linksys boxes. Perhaps those ‘cantenna’s will also be home to nesting birds in the spring. What about the 100 mph wind certified green duck tape and the hedge-trimmer yagi. But don’t worry, those all seem to be low-loss cables and completely lightning proof.

Priceless!

Then in my own business I’ve been through literally 50+ bags that have been ‘mine’. But now I’ve used the same backpack for over three years now… a World’s Record!

I had some time last week and I thought I’d document up what is in my Backpack.

I have had many years of travel experience and have honed my packing skills to bring along just the right set of equipment and supplies to support me wherever I might be. I can work, be entertained, read, relax, and generally take pretty good care of myself with just what is in my backpack.

Every item on this list has a specific purpose and reason for being included. This backpack has to fit in the overhead compartments of even the smallest of Regional Jets, or under the airline seat. And… I have to carry it with me and send it through TSA security checkpoints over 100+ times per year!

This combination of equipment is the culmination of thousands of hours of travel and on-the-road work. Work in Hotel rooms, Crown Rooms, Airports, client offices, backs of bouncing pickup trucks, subways, and even at my home and work offices…

Everything can be recharged via USB 5v systems – and I carry two spare 5v batteries and three USB Charging stations so I’m never without power for these devices. Everything is also 110v/220v so I can travel internationally. Depending on the country, I just have to add a small bag of adapters and I’m ready to go.

So here it goes…

__________________________________

Keith Parsons – Backpack Contents

Backpack

- Brenthaven Expandable Trek Backpack

In Bottom of Front Pocket

- Main Unit – Small case I can pull out and easily setup on a desk
32GB USB Drive – Corsair – Backup and All my install files
USB SD Card Reader
USB Charging Battery – Lennar
USB Charger Cable for iPhone
8GB USB Drive – Temporary Files
16GB USB Drive – Instructor Master
8GB USB Drive – Aruba PTT Course
Flashlight – Surefire Executive Defender
Mini Cable to VGA for MacBook
Red Pen – Bic 5mm
Black Pen – Sharpie Mini
20GB Firefly USB powered Hard Drive
CarryAll – NiteIze Mobile Accessories
- USB Charger w/Dual adapter iPhone and Mini USB
- Apple AirPort Express Extreme – set to WPA to share Wired
- 60Watt Apple Macbook Power Suppy
- Allsop Mouse Beanbag
- Apple Bluetooth ‘Mighty Mouse’
- Canon Sureshot Digital Camera

Charging Unit

Tums EX
Toothpick
Tube of Tylenol Extra Strength
Cherry Chapstick
Ceramic Paper Cutter
Fingernail Clippers – A.G. Russell
Fingernail File
Twezzers – L.A. Cross
USB Charger Cable for Kindle
USB Charger Cable for Mini USB
USB Charger Cable for iPhone
USB 4-port Hub – APC
USB AC Charger – Lennar
USB Charging Battery – Lennar
USB Male to Mini USB Cable – Zio Shorty
USB AC Charger – Apple
CarryAll – NiteIze Mobile Accessories

Network Unit

RJ-45 to DB-9 Console Cable Adapter – Aruba
USB to DB-9 Serial Adapter -
USB to Serial Converter w/cord
USB to Serial Drivers Mini CD
RJ-45 Cross Over Adapter
3′ Cat-5 Cable
6′ Cat-5 Cable – Retractable
4-port USB Hub with Octopus Cable
AirMagnet abgn Wireless LAN Adapter w/AirMagnet Licenses
Ubiquiti abg Wireless LAN Adapter w/2dBi Antenna w/AirMagnet Licenses
CarryAll – NiteIze Mobile Accessories

Back Main Section

Spare Bifocal Glasses in Protective Case
Spare Computer Glasses in Protective Case
Sunglasses in Protective Case
Package of M&Ms
Package of Salted Peanuts
Monster ‘Dr. Dre’ Noise Cancelling Headphones
Amazon Kindle2 in Leather Case
Apple Macbook 13″ – Aluminum Unibody 2.66GHz w/500GB HD
Monster Cable – 4-port Portable Power Strip
Passport in Mesh Liner
Wallet ‘spare’ ID and Credit Cards in Mesh Liner
Cash – $300 in $20s

Right Side Pocket

Garmin Nuvi 250 Portable GPS
w/Suction Mount & USB Charging port
Outside Mesh used for loose change
Ball Speaker – USB Powered

Left Side Pocket

IO Scribe Digital Pen
Portable Microphone
Earbuds w/Airline Adapter
Variety of Medicines in Single Serving Packets

Front Left Zipper Pocket

Car Keys
Ninja’ Remote
Eyeglass Cleaner Pads
Pre-moistened Lens Cleaning Tissues

Front Right Zipper Pocket

Tide Stain Remover Pen
Fingernail Buffer Tool
Large Pre-Moisten LCD Cleaning Tissues

Front Zipper Pocket

Spare Mont Blanc Rollerball Pen
Spare Mont Blanc Rollerball Refill
Airline Coupons and Pre-Paid Vouchers
Spare Red Pens and Sharpies
Sleeping Eyemask and Earplugs
First Aid Kit

Front of Backpack

S-Biner Snap-On Caribiners – 10Lb Versions
Altoids Sugar-Free Wintergreen Smalls
Delta Skymiles Platinum Medalion Tag

Top Front Pocket

V-Mode High-Quality Earbuds
Airline Adapter for Headphones
Motorola Bluetooth Earpiece w/USB Charging Port
Spare AAA Batteries
USB Charging Cable for Ailph Jawbone Bluetooth
Aliph Jawbone Slim Bluetooth Adapter
2GB SD Card
Business Cards
3×5 Cards PrePrinted with my Information and Grid Patter
Small Narrow Notepad
2″x2″ Yellow Post-It Notes
Spare Mont Blanc Rollerball Refill
Microfiber Cloth
2GB ‘Temp’ USB Drive
4GB ‘Master’ WLAN Student USB Drive
Crown Room Card
Delta Airlines Platinum Status Card
United Airlines Gold Premier Status Card
United Red Carpet Lounge Passes
Small Leather Case to Protect Jawbone2 Bluetooth Adapter

This was brought home this past weekend. My daughter had a little ‘difficulty’ with her phone, and was without it’s capabilities for awhile. It was driving her ‘crazy’ – being without her phone was actually quite devastating to her young life. Not being able to contact her friends, respond to SMS, no longer have her music, etc.

Through a series of horse-trading, Genius Bar generosity, and a little cash we were able to not only get back her phone in working condition (not actually her phone… but one pre-loaded with all her contacts, music, SIM-card, etc.) as well as a ‘spare’.

Earlier in a previous blog entry I waxed a bit poetic about my relationship with the iPhone, how it is there to wake me up in the morning, keep me informed and communicated with during the day, and entertains me whenever I have a ‘down’ moment, lets me read a book during dinner, and reads a story to me when I’m on my daily walks… it has become part of my life. Another previous post about my upgrade to a 3GS also talks about how I use this technology in my personal and business life.

So now I’m feeling just a bit ‘safer’ – that ‘Peace of Mind’ that comes when you know you have a disaster recovery plan already in place. That good feeling that comes along with knowing you have redundancy built-in to your network. Knowing if one of your controllers goes down, the ‘spare’ that you took so much time installing and configuring will allow your wireless users to continually merrily on their way.

I know have that feeling! – I have a new–still in the plastic wrap– ‘spare’ iPhone in my backpack. If there is an accident and my current iPhone goes down, I can quickly swap the SIM card and be on my way. Now that is a great feeling. Now I know how my clients feel when we finish designing a fully redundant system. Aaahhh. Peace of Mind.

These are useful to mount USB Wireless Devices to the back of your laptop lid, out of harms way, and not sticking out dangerously from the sides of your laptop – ready to break off with the slightest bumping and jarring.

I also carry a couple iPhone charge/sync cables with me (just in case…) and these short little ones fit just about anywhere and stay out of the way until you need them.

I enjoy having more space in my bags and not having to ‘wrap up’ the longer cables I used to carry with me.

A big ‘thumbs up’ to these folks who obviously listened to what the industry needed!

You can find these at the ZioTek website.

As a consultant and trainer in the Wireless Networking arena – I’ve found this little app well worth the $7.99 cost. (OK, I know it seems like a lot when compared with other ‘free’ apps – but it is truly a small cost to pay for this functionality)

It will run on either an iPhone or an iPod Touch.

I’ve got an iPod Touch dedicated to just running tools and apps for Wireless LAN Professionals, this post will turn into a continuing review of the tools and techniques I’ve found that help in the craft.

This app comes with both RF Tools and GPS Tools

For you ‘indoor only’ kind of networking guys – this tool has parts for you. One of the calculators is for Link Budget Analysis, another that will be of use to you is the dBm/Watt Converter.

The real strength of the app is in helping the ‘outdoor type’ folks with their Wireless LAN deployments. Supporting these installations are Fresnel Zone, Downtilt Coverage, Free Space Loss and other important calculators.

But in the GPS set I find myself using the Lat/Long Conversions most. AirMagnet Survey Pro requires it’s GPS coordinates in decimal format, and Google Earth keeps theirs in Degree, Minute, Second format – so I use this calculator to move back and forth between the two.

This tool is Highly Recommended – ***** (that’s five stars)

Jess Silverstone from Revolutionary Concepts created a cut-out of the iPad that you can print and glue/tape up yourself!

Paper iPad Print

Paper iPad Finished

Click here to download the iPad Front and iPad Back. Have really big printer? Check out this PDF created by a Taiwanese fellow that will let you print to full size.

Enjoy!

I saw this first at http://iPadinCanada.ca.

One of those has to do with the ‘Gross‘ versus ‘Net‘ data throughput results with respect to Wireless LANs. Just because the stated data rate is 11Mbs, doesn’t mean you’ll actually get 11Mbs of net throughput.

For 802.11b – the max stated rate of 11Mbs works out around 5.5Mbs of net throughput. It is NOT the “half-duplex” nature of RF communications that is lowering the throughput, but the rest of the 802.11 protocol. Though many people make this incorrect assumption.

The ‘net’ throughput is brought down by overhead inherent in the protocol itself.

• Time wasted in the DIFS delays
• Time wasted in the Contention Window Delays
• Time and Bits wasted in Preambles
• Time and Bits wasted in SIFS/ACK delays
• Time and Bits wasted in RTS/CTS with their associated Preambles and SIFS delays
• Time and Bits wasted in large MAC Headers, etc.
• Time and Bits wasted in MAC Layer Fragmentation (Extra Headers)

Those are the real reasons you have a lowered net throughput.

In a typical packet exchange below lists those parts that are overhead – some are based on wasted time, and others on wasted bits – then there are parts that contribute to net throughput.

DIFS

Contention Window Delays

Preamble

RTS

SIFS

Preamble

CTS

SIFS

Preamble

MAC Header

Data frame payload

SIFS

Preamble

ACK

Only the actual payload of the Data frame contributes to the net throughput. Everything else in the packet exchange, time wasters like DIFS/SIFS and contention window delays, as well as all the other parts are just overhead. But it’s the use of the overhead that makes the 802.11 protocol actually work in a sometimes harsh RF environment.

It is a ‘ratio’ of those wasted time/bits to the total time/bits that takes you from gross bits in the air, to net bits of payload throughput.

This comes to bear with much more evidence as you delve into the 802.11n packet structures and their effects on throughput.

Again, it is NOT a result of only the half-duplex nature of RF communications – but the actual protocol itself.

For further information on this process, check out Marcus Burton’s great white paper 802.11 Client Arbitration.

I would appreciate your thoughts and comments on this subject. Thanks!

The first three episodes are now available either from the Website or on Apple’s iTunes.

Even though it is called a ‘Podcast’ you don’t necessarily need an iPod to listen. The files are standard MP3 – and can be listened to on an iPod, Zune, portable MP3 player, or just on your computer. In fact you can listen in directly from the web site as well.

The goal of the podcast is to educate, inform, entertain, and inspire folks who work day-in, day-out with Wireless Networks.

We bring you weekly information from a wide variety of contributors. The host is Keith R. Parsons, and each week he has at least two others helping with either tech or soft-skills related content pertinent to Wireless LAN Professionals.

Come join in the community of your peers!

If you want to see both sides of the conversation, follow me in Twitter (@keithrparsons) and also follow whomever I’m talking with.

If my post starts with an @name – this means I’m responding to that person. So there was a part of the discussion that went on before.

If my post starts with a ‘RT @name‘ – this means I’m re-quoting something someone else said.
After the quote I might add my own comment.

Sometimes I’ll embed a picture in my post. This will look like the following URL http://twitpic.com/qqy53 (BYU Spring Lax Schedule)

Sometimes I’ll embed a link to another web site using a ‘URL Shortener’ service. It looks like this http://tinyurl.com/yabdexb

Remember, you might be reading these posts in reverse order, so start at the bottom of the conversation.

And finally – sometimes I might add a hashtag. So others can follow the topic easier online. These will start with a # followed by a tag.

Sometimes I’ll make comments about Technology, sometimes about my Professional Interests, or other times just what I’m doing.

Sometimes I use this forum for ‘mini blogs’. Short 140 character comments. If there is more to say I might post a larger blog entry.

If there is a blog entry – I’ll post it with a URL so you can link to the larger blog post. At either my personal or professional blogs.

Further questions? You can reply in Facebook, Twitter, or drop me an e-mail to keith at inpnet dot org.

Some are pretty funny. Thanks Devin for allowing me to cross post these on this blog!

Silicon Valley Lingo –> Georgia Slang

Set expectations properly –> Don’t make stuff up

Take his temperature –> See if he bit

Rock Star –> Work Ethic

Reaching –> Probably won’t work

Win-Win –> Everybody’s gittin’ somethin’

Chunky deal –> A big, fat deal

Clunky –> Crappy, Ugly, or Just Dumb

Kludgey –> Screwed up (or FUBAR)

Streamline –> Shape up or ship out

Tighten up –> Get your ducks in a row

Bubble up –> Hit my radar

The operational analysis shows… –> See, what had happened was…

Hitting a roadblock –> Gumming up the works

High burn rate  –> blowin’ through all your cash

Non-starter –> That dog won’t hunt

Sentences ending in “…my friend” –> somebody isn’t happy with you about something

If you want to see both sides of the conversation, follow me in Twitter (@keithparsons) and also follow whomever I’m talking with.

If my post starts with an @name – this means I’m responding to that person. So there was a part of the discussion that went on before.

If my post starts with a ‘RT @name‘ – this means I’m re-quoting something someone else said.
After the quote I might add my own comment.

Sometimes I’ll embed a picture in my post. This will look like the following URL http://twitpic.com/qqy53 (BYU Spring Lax Schedule)

Sometimes I’ll embed a link to another web site using a ‘URL Shortener’ service. It looks like this http://tinyurl.com/yabdexb

Remember, you might be reading these posts in reverse order, so start at the bottom of the conversation.

And finally – sometimes I might add a hashtag. So others can follow the topic easier online. These will start with a # followed by a tag.

Sometimes I’ll make comments about Technology, sometimes about my Professional Interests, or other times just what I’m doing.

Sometimes I use this forum for ‘mini blogs’. Short 140 character comments. If there is more to say I might post a larger blog entry.

If there is a blog entry – I’ll post it with a URL so you can link to the larger blog post. At either my personal or professional blogs.

Further questions? You can reply in Facebook, Twitter, or drop me an e-mail to keith at inpnet dot org.

I posted a previous detailed review on my blog post earlier this year in April. This is an updated list to reflect updated apps and how I actually use these apps in my daily work. These are based on a review of over 100 network apps purchased and tested over the last few months.

Try them yourselves – I think you’ll enjoy using your iPhone as a nice portable network analysis tool.

If you want to see the full 100+ apps, icons, pricing and features. Drop me an e-mail at KEITH at INPNET dot ORG and I’ll send you the spreadsheet in Excel and PDF form for your review.

____________________

Tier One Apps
____________________

Deep Whois – Professional Whois Browser

NetBrowser – does Multicast DNS searches (Bonjour) with nice details

Bytes – does dec/hex/bin conversions, ASCII reference and metric units

My System 2 – gives you System information as well as Local station info

ASCII Chart – the best of the many ASCII reference apps

My Network Ports On-The-Go – detailed analysis fo the port database

Pinouts – Details on RJ-45, Firewire, USB, etc.

Emerald Time – NTP Accurate time

iNet – Professional robust network tool with Scan, Bonjour, Portscan & Device Info

Net Scan – Scan IP, Range, Country, MAC, Whois, ICMP, TCP

Network Diagnostics Pro – Ping, Ping Range, Tracert, DNS, Device Info

Snap – Local Scan, ID Devices, Bonjour Services, detailed export

Net Status – Professional TCP, UDP update and MAC Lookup

Nice Trace – Professional Trace, Whois, Country and Details

TCPinger – Both ICMP and TCP Ping with details and ‘What’s Up’

RF Toolbox – Very well done RF, GPS and Site tools for Wireless Pros

IP Calc – the best of the myriad of Subnet calculators

iPico SIP Client – a fully configurable and robust SIP Client

Skype Client – yep – just what you think

WiFiFoFum – best ‘NetStumbler’ around for iPhone – Get it!

FTP On The Go – FTP App with Viewer capability

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Tier Two Apps
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DNS-SD – $2.99 – Browse Bonjour Services
nDNS Watch – $0.00 – Browse Multicast DNS Services
Network Solutions Whois – $0.00
iNetCalc – $0.99 – Calculate file transfers, bandwidth, VoIP
SpeedCalc – $0.00 – Calculate file transfer times
iNetInfo – $0.00 – Quick MAC, IP, Gateway, DNS
File Name Extension Reference – $0.00 – Yep, just hat is sounds like
iHexView – $0.99 – Base converter for bin/dec/oct/hex
IT Tools – $2.00 – Ping, Route, Interface, ARP, MAC Database
IP Port LIst – $0.99 – Reference Tool for IANA Ports
RF Calc – $0.00 – CWNP RF Calculators from G.T. Hill
IP Calc – $0.99 – Best Simple IPv4 Subnet Calculator
IPEToolbox – $0.99 – IP Engineer’s Toolbox with Subnet, VoIP bandwidth
NetCalc – $0.00 – Easy to use Subnet calculator
The Mask – $9.99 – Professional Extensive IPv4, BinHexDec, VLSM, CIDR
Acrobits Softphone – $6.99 – Customizable SIP Soft Phone with easy setup
WiFiTrak – $0.99 – WiFi Scanner with Connect
Datacase – $6.99 – WiFi Drive Apps with Viewers
iDisk Mobile Me – $0.00 = Access your Mobile Me iDisk

We in the US are no where near the top on this one… shame on us! Not to mention, we are paying too much!

Check it out.

All of this fits in the front pocket of my backpack – is easy to use, easy to pack up, and makes for a consistently successful work environment for me.

Of course I have other stuff for in-flight entertainment, like my Amazon Kindle2 for reading, my iPhone 3GS for music and watching movies, and my wonderful Dr. Dre Noise Canceling Headphones. Those all go in the larger section of my backpack with my MacBookPro 13″ Unibody laptop.

The below travel kit is the ‘supporting stuff’ that makes working away from home and office ‘work’. After many attempts at finding the ‘just right’ bag for hauling stuff around I finally have ended up with a neoprene bag made for carrying charger bricks… I use it as a place to house most of this kit in one place. Easy to pickup – use – and put back. Enclosed in that kit are the following items – tucked into one of the six soft pockets of the bag.

AT&T USB Connect 881 – this 3G device lets me get Internet connection even when there is no WiFi available. As long as there is Digital Cell service – I can get on the ‘net’. Syncharger Dual cable – allows for me to charge USB powered devices, my iPhone and also sync my iPhone when needed. Spare Cat5 Cable to connect either wired Ethernet, or the Apple Extreme to be able to share wired Internet wirelessly. DisplayPort to VGA adapter so I can project my Mac to a TV or LCD projector when needed.APC 4-port USB port – so I can have multiple USB devices all sharing a single USB port – Small and compact. Two Zio Shorty USB cables – one to ‘mini’ port and one extension. Apple 45w Power supply for MacBookPro – with ‘stub’ power so I don’t need another power cord. Apple AirPort Extreme N - supports 802.11n and allows me to ‘share’ wirelessly wired connection. Great for running Skype or a SIP phone on the iPhone when overseas – and have multiple computers share a single hotel Internet connection. Invaluable! Kindle2 Power Charger – Not just for the Kindle2, but I use the USB power base to charge other USB items with differnet cables. Monster Power2Go – a 4-port power strip – small and the power cable folds back on itself for compact storage.In the bottom of the front backpack pocket I aslo put the following items:

• Two Western Digital ‘Passport’ 500GB drives – one that contains a full backup of my MacBookPro, and the other with ‘working’ documents, all my MP3 files, and hundreds of movies – both with Zio Shorty USB cables placed in a Case Logic portable hard drive case.

• A Stanley 12′ extension cord – very useful in hotel rooms without power by the desk, or to get power while waiting in an airport.

• My latest addition is the amazing Kbex portable speaker systems from a previous post. This thing really works!

So that’s what I carry with me. It helps a lot to the the right items with you when working on the road.

I’ve logged nearly 2 million miles in the last 15 years – and have gleaned some experience from all that travel.

In no particular order:
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Camera Strap – Black Rapid’s RS-4
This strap is a new way to carry your D-SLR camera. Instead of a strap going around your neck, making the camera bounce along in front of your stomach – this strap is designed to mount to the tripod mounting hole in the bottom of your camera – and then go over one shoulder/neck, thus the camera rides easily off your back/hip and yet is still very easy to bring your camera up to eye level for a picture.This was a fantastic upgrade to my old Nikon camera strap. Much easier to carry a large camera all day – yet still very user friendly and easy to learn. Highly Highly Recommended!
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Travel Clothing
When teaching – I just wear dockers and a long-sleeve button-down shirt. But then again, those days are spent all inside teaching. But when traveling, or doing sightseeing I like to wear specially made travel clothing. A shirt with two front pockets (passport/tickets/iPhone/glasses) for flying and sight-seeing. Pants with more zipper pockets to help deter pick-pockets and are very lightweight.I’ve found it to be very difficult for pick-pockets to access shirt pockets that are buttoned – a person is much more protective of the front chest area – especially in a crowded area like the subway. Even with extra zippered pants pockets, I’ve found pick-pockets now how to work the zippers. So the wallet and cash go in the right front shirt pocket! (and the camera strap also covers right over that area for even extra security)

It might cost a bit more, but it is made for easy care, functional, and nearly wrinkle-free.
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Apple iPhones are Everywhere!
I thought our family was a bit on the edge with most of us having iPhones. But more and more I’ve been seeing iPhones everywhere. They do have a distinct look, so they are fairly easy to spot. More people on planes, hotel lobbies, and now even all over Europe the iPhones have really taken hold. I really enjoy mine, and find it to be not only a great phone, but a game platform, contact lists, calendars, to do list, Internet access, alarm clock, GPS, iPod for music and portable movie player.
No wonder they are everywhere!

This is also very highly recommended.
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Big Zoom Lens
I’ve got an older body Nikon D40 as the base… but put the extra money into a very nice lens. The Nikkor 18-200 VR lens is a great single lens to take on a trip. Not only can it let you capture wide-angle panoramic scenes, but lets you zoom way in. As a single lens it does just about all you’d want. And with the Vibration Reduction elements, you can shoot in much lower light conditions, even taking hand-held shots.Some of the shots inside the Cathedrals of Europe where made with just this lens in a hand-held position. A great addition to your camera bag. I’d opt for this upgraded lens and save money on the camera body – oh yeah, I already did that.All the pictures on my personal blog as well as my son Ryan’s facebook were taken with this lens.
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England, UK, Britain Confusion
Check out an earlier blog that answers these questions.
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Skype – the ONLY way to call
I pre-loaded Skype on the iPhones before heading off to Europe. On previous trips, I’ve used a variety of methods to call home. Small WiFi phones, Skype specific phones, headsets and Skype on my laptop. But Skype on the iPhone was very easy to use. My wife Jill and daughter Alysha both have iPhones, and it was a simple transition to just use the Skype App rather than the normal Phone App.This saved us $$$ – especially with the daughter calling home to her boyfriend (they liked to talk…) At only $.02 per minute (an hour-long call only cost $1.20) it was great.In order to make the Skype phone work – you need to have Wireless Network Access. See following note.
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Bring your own Access Point
I travel with an Apple Airport Express – little guy – but packs a pretty good punch. I have it programmed with WPA for security, and it is easily 110v-220v capable. And it is 802.11n to boot!This just plugs into the hotel’s Internet – then you do everything via WiFi. This lets us all share WiFi in the hotel. 4 iPhones and three laptops all using one Internet connection.

I’ve tried 5 other ‘travel routers’ but this is the smallest, simplest, and easiest to use. At only $99 – don’t leave home without it!
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Pack only what you need
You can usually get just about anything you might need locally – if you need it. If you don’t need it, why schlep it all over the world?

I use a very nice bag from RedOxx out of Montana. A single bag is a great way to travel. Easy, you can (if you have to) use it as carry-on. (see additional item below on carry-on luggage) – but it can easily hold a week’s worth of stuff.Minimize the ‘extra’ stuff you ‘think’ you might need. Just learn to live with what you have and be glad for it. If you *really* need anything else – buy it locally.
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Know you own bags!
Another little pet peeve of mine with regards to luggage. At the baggage pickup, when people pick up and check bag after bag, trying to find their own. You just put in on the plane a couple of hours ago, you’ve already forgotten what it looks like?

If you need to easily identify your bags, just tie a piece of colored yarn or ribbon to the handle (or buy those ridiculous large luggage tags in bright green)
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Airline Carry On
Just because you *can* take a bag on carry on doesn’t mean you *should*! Be a bit considerate of others on the plane. The overhead compartments need to be shared by everyone. And me, for one, ALWAYS put my backpack in the overhead compartment. I’m not going to travel uncomfortably with my feet wrapped around a piece of luggage. Don’t ask to put your second carry on under my feet – just don’t bring it on the plane. They have an entire baggage system to get your bag to where you are going!

Out of 2million miles of travel – I’ve have the airlines loose my bags on 9 times, and 5 of those were on my way home. So out of hundreds and hundreds of flights I’ve had to do without my bags 4 times. This is not the risk you are making it out to be. Pack an extra set of underwear in your carry on and be done with it.
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Always have pen and paper with you
I was taught by my father – and hopefully I’ll pass it on to all my children – to always carry a pen with you! It is a sign of maturity and preparedness!

Also, within the last couple of years I’ve also started to carry 3×5 cards in my pocket. These have also been invaluable at times. Someplace to write little notes, take informaiton down, jot down a phone number or address.

Even in the age of iPhones – an index card in your pocket can be a great thing.

Always have a Pen and Paper with you!
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Get money locally
When you travel to different countries – it is so much easier (and way cheaper) to just get money locally from an ATM. They are everywhere. Don’t waste your money, nor your time at the money changer places.

You use an ATM for cash at home, use one abroad as well!
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Don’t Stink
This is to all the folks in Europe (and a couple in the States) – It is possible to have personal hygiene and not STINK! – Alysha would cover her nose with her hand when on the subways in Europe because all the body odor, and smell of unwashed clothes.

It’s not that hard to clean yourself and your clothes! Just do it!

I think I blame the women in Europe. If they wouldn’t have anything to do with these stinky men, the men would soon learn to change and worry about personal hygiene. The European women must like that smell of old sweat and wool… yeck!

If you haven’t washed up your person or your clothes – don’t travel! Sitting next to one of these on flights is nearly unbearable. They don’t even seem to notice.
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Have stuff with you
If you need medicines, take them with you in your carry on. If you like to read, have a book with you, watch movies? take along an iPhone of iPod Touch. Just be prepared. Worried they won’t have food for you, bring your own.
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Kindle & iPhone
Between these two little devices I can keep myself occupied for hours, even days.

My Kindle has hundreds of books just waiting to be read – waiting for me to have some ‘down time’ to read them.My iPhone is full of great games, audiobooks, Internet, and videos. If I’ve got time, I’ve got a way to spend it.
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Relax
There is usually nothing you can do to change travel fiascos around you – so just be prepared with media of some type and just enjoy the extra time. You can’t change anything – so don’t let the stress get to you.

Enjoy!

The topic was Pre-Shared Keys and some of the new techniques Aerohive and others are bringing to the table. You can find the discussion here.

Thanks to Bruce and Ken for their comments.

To this end we work hard to get the correct number of access points with the proper power and channel settings using the best antenna patterns to cover the area we are interested in. In the simplest terms, there are three design specs to consider.

First there is the ‘Want‘ – what we are designing for.

Second – the ‘Don’t Care’ – the level of RF that we don’t care about.

Third – In between the above two items – ‘Don’t Want’ – where we find same-channel (co-channel) interference.

Want

In the ‘old days’ when we employed the ‘AP on a stick’ method of site surveys in a pre-deployment mode, trying to come up with the best possible design, we’d end the survey with a design showing access points and their ‘coverage’ patterns. (sometimes called a heat map – though it had absolutely nothing to do with heat)

In this ‘AP on a stick’ process, after placing an access point in a temporary position we’d walk away until we reached the lower limit of our design goal. Perhaps -70dB or -67dB… then we’d stop. We met the design goal in that direction, so we’d stop.

But the RF energy projecting from the access point in question did not stop, it kept going. Since we never completed the Site Survey to the end of the radiation pattern, our designs did not, and could not, tell us where we’d run into interference with other access points.

This would give us what we wanted… Thus this is the WANT area.

The want area is normally defined to meet a specific design requirement based on the devices we’re designing for. Perhaps a -67dBm for voice, or a -75dBm for a hand-held scanner device.

This is the ‘easy’ one. Remember “Coverage is Easy”. See other article on “How to Spec your Physical Layer”

Coverage patterns looked something like this, with nice simple circles all lining up in neat rows.

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NOTE: the -67dBm, and -86dBm used in the following examples are SAMPLES ONLY – Not indicative of any specific design!!

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Don’t Care

Lets talk about the second RF design consideration next. This is the area where there is RF radiation, but at a level that is below the threshold of our device to actually use.

I call it the DON’T CARE area. In the don’t care area, there is too little RF to make the client (STA) stop and wait for another client or access point to finish talking.

In other words, the amplitude of RF signals in this area are too low to be considered in the frequency’s collision domain.

With AirMagnet Survey, we can raise the color bar on the right side to make the areas with signals weaker than a given threshold turn grey.

This is usually set to -85dBm, but some devices are more sensitive and you might need to set your Don’t Care to -90dBm.

Don’t Want

Now we get to the difficult one. This is the one we normally don’t even measure in an ‘AP on a Stick’ survey.

One vendor draws their graphics to explain this, as shown in the following diagram. Note the WANT area is inside the dark circle, and the RF that is less than the desired goal still continues to radiate, causing interference and a large collision domain to all devices within the larger circle.

The trouble isn’t when two access points are next to each other. Since we have channels 1, 6, and 11 to use as non-overlapping channels, we can have a little ‘buffer’ between the same channels.

The problem starts when we don’t ‘look’ to see where the DON’T WANT area is in our survey. We never notice the access point’s RF that is less than what we want, which continues all the way past the buffer zone and into the next sam- channel access point’s space.

One graphic from a vendor details it like this.

This graphic shows that you must keep at least a 19dBm difference on the same channel from the ‘want’ to the ‘don’t want’ areas.

Another way to look at the situation between same-channel coverage pattern overlaps looks like this.

I ran a little online survey, and folks were just about evenly split between the above graphic and the following graphic.

I think an easier way to explain this situation is to turn the graphic on its side, like this.

Leaving the access point on the left, the RF propagates and looses RF energy along the way until it reaches the design goal, or the want line. We normally stop at this point in our surveys, but you must continue on to see where the RF continues.

The signal degrades and attenuates as we go further to the right, eventually reaching the level at which we no longer care. This is the don’t care line.

In between the access point on the left and the access point on the right is the area that is below the design goal threshold. This area should be covered by the other two access points on channels 6 and 11.

Coming back from the right, we have the same thing. The access point on the right on channel 1 starts strong, and as we move to the left, continues to get weaker until it reaches the design goal (want). After that, there is still RF on channel 1, but it is below our goal, and thus falls into the DON’T WANT area.

Another name for the don’t want is ‘Interference.’ If the two access points on channel 1 are too close, the signal from the right AP will interfere with the signals from the left AP.

In order to get access points on the same channel closer together (get the angles of the dropping signals to be steeper), you must lower the power.

Higher power gives you a longer ‘tail,’ and lower power give you a shorter ‘tail’.

Setting AirMagnet AirWise Interference Settings

In AirMagnet AirWise, there is a feature that allows you to visually show where interference meets or exceeds the design parameter. Remember, different devices have different design parameters.

To set the Want, Don’t Want, and Don’t Care values in AirWise we need to re-label them to meet the AirMagnet vocabulary.

The end of the want area is the same as your design goal for Minimum AP signal strength required.

The end of the Want value IS the start of the Don’t Want area (if it is below our want, it must be our don’t want) In AirWise, this is labeled with a weird English phrase of “Interfered APs: Exclude APs signal if strength is weaker than.”

The end of interference, where the signal is below the threshold of causing any harm, is called the Don’t Care. In AirWise, this is labeled with a second instance of the phrase “Interfering APs: Exclude APs signal if strength is weaker than.”

Conclusions

So there you go; simple, easy terms to define where you Want RF, where the RF signals on a specific frequency will cause interference — Don’t Want — and the area where the signal is too weak to make a difference — Don’t Care.

Additional Article for Support of WLAN Site Surveys
- 7 Rules for Accurate Site Surveys
- How to ‘Cheat’ Using Survey – Don’t be a Victim
- How to Properly Analyze Survey Data
- The Fallacy of Channel Overlap
- Predictive Survey vs Onsite Survey – What’s the Big Deal?
- How to ‘Spec’ your Network’s Physical Layer
- Want, Don’t Want, Don’t Care – Meeting Design Specs
- The Truth about SNR – Where Did that ‘N’ Come From Anyway?
- What is an Access Point Anyway – Hub, Bridge, Switch or Router?
- Passive vs Active – What’s All the Fuss About?
- The False God of dB
- Meeting All Device Design Parameters

The couple of little things that bothered me, namely the smaller keyboard, and the lack of the standard Macintosh two-finger scrolling and two-finger right-click.

Well, this week I did an update to the OS X operating system to the latest 10.5.7. It totally crashed the little guy… until I went online and learned a couple of ‘tricks’ on how to let the software/hardware find itself all over again. Now we’re fine!In addition – and to my great surprise – I also found the latest drivers that allowed me to make the little Hackintosh’s trackpad act just like a real Macintosh! I now have two-finger scrolling and two-finger right-clicks working. Yea!

No software is going to make this little keyboard get bigger all of a sudden – so I guess I’m stuck with that.

The little Hackintosh makes a great second computer. I take it on all my trips. I’ve pre-loaded the 64GB Solid State Drive with a bunch of TED Talks, Movies, etc. so it’s a small little lightweight entertainment device for use on the plane.

In addition, it has an SD slot on loaded with even more movies on a 16GB SD card.

This has been a very fun little project!

On her trip to NYC with the High School Fashion Team, my daughter used it as in-flight entertainment, and to check her e-mail and update her facebook page during the trip. (WiFi in the hotel worked great)

Since I’ve got all my ‘important’ stuff like Calendar, Contacts, E-mail, etc. all sync’d to Mobile Me – it was a simple exercise to get the Hackintosh to also sync to Mobile Me. Now it is a nice ‘backup’ laptop if anything happens to the ‘big brother’ (my main machine – the Macbook 13″ Unibody).

And for everyone reading this – Backup your data today!
(a quick message brought to you by our sponsor… Your conscience)

If you’d like your own Dell Mini 9 Hackintosh, just drop me a line and I do my best to help out.

From my Twitter posts – http://twitter.com/keithparsons or @keithparsons

Dell Mini9 Hackintosh *lives* once again. Just had to do a bit of ‘tweaking’. Yea! – Instructions here http://bit.ly/EUes4

Hackintosh is even better than before! Now with 2-finger scrolling, and 2-finger right click! Yea! Instructions here http://bit.ly/oQLpw

The FULL data set, not just AIDS, but education, life expectancy, income, births per woman, and many many others are all available. But best of all there is an easy-to-use interface that allows one to pic the variables, and then watch how things in the world have changed over the last 200 years.

This is a *fantastic* tool to learn and understand differences in countries, cultures, and how we all fit in this world. It’s amazing to see how the world has changed over time.

There is something about having the freedoms, liberty, captialism, etc. that has allowed this ‘winning’ way. The US is NOT the best at everything – this data from world statistics shows that. We have problems and issues – that’s true – but I’m pretty glad to be an American anyway.

Please spend some time learning – and I mean that – LEARNING from the historical data and statistics at this site. It will be good for you to think about the ‘whys’ of some of these.

Here’s the site.

A couple of places to start – AIDS -vs- Income, Number of Children per Woman -vs- Income, Life Expectancy over time, just to get you started.

Enjoy – and please share your insight you learn from evaluating this information. Why does the world work like this?

Some TED Talks that might help
Best Stats You Have Ever Seen
Insights on Poverty
Truth about HIV

Books, white papers, study guides, and design manuals have touted the value of the RSSI (dB) so much we have used this as a sole way of designing and evaluating our Wi-Fi Networks. dB is a false god and we need to mature and move past having ‘Signal’ be our main goal in WLAN designs!

Signal is Immensely Important!

I’m not in the least bit saying Signal levels – RSSI – is not terribly important in our WLAN designs. It is critical, required, and even mandatory. But RSSI alone is not sufficient.

To give an analogy of a wired network, consider connectivity. It’s the ability of copper pairs to conduct electricity at a certain level, and it’s paramount in getting wired networks to work.

dBm is to a WLAN what connectivity is to a Cat6 cable. It is a base level requirement. Without it, nothing works.

Compared with Category 6 Cabling

But just as connectivity in a Cat6 cable isn’t the only factor in determining whether or not a cable run meets the design characteristics, RSSI (signal strength) isn’t the only factor in determining whether or not a wireless network meets its design characteristics.

Cat6 cable actually means cable that meets the Category 6 physical requirements as defined by the TIA/EIA organization. These requirements include:

• Connectivity
• near-side crosstalk
• far-side crosstalk
• pin-outs
• cable twist ratios
• and more

Much more than simple connectivity alone!

In a WLAN design, a certain level of signal strength is required, but signal strength alone is not sufficient. We have yet to find a wireless industry group to take on the responsibility of defining the specifications for a ‘voice-grade’ WLAN or a ‘video-grade’ WLAN, let alone even a generic ‘data-grade’ WLAN. We are still in the early stages, and each vendor is still defining their own specifications.

WLAN Design Specifications

I’ve started a new project working with other CWNEs to develop a WLAN Design Matrix to help codify and analyze the various vendor recommendations for design parameters to make their client devices work on WLANs. As an example, VoWiFI devices need specific dB, overlap, jitter, latency, packet loss, DTIM intervals, etc.

In this early stage of the process, we have already defined nearly one hundred unique identifiers and specifications collected from the various WLAN vendors. Of course the first one is always ‘RSSI’ – or Signal Strength defined in dB – but that is merely a baseline. On top of the Signal Strength, there are many more categories of WLAN requirements.

Some vendors require an ‘Overlap’ (see my blog post on the fallacy of channel overlap ). Other vendors specify the co-channel interference at very specific levels. Still others add data rate support, number of devices per AP, minimum MCS requirement, and many more.

Some of the requirements are based on designs for the STAs (clients), and others are specifications for the Access Points and cabling. Together all these requirements must be met in order to deliver a WLAN infrastructure that will work with the vendor’s devices.

Do you know all the design specs for your Wi-Fi enabled client devices?

How can you tell if your WLAN meets those specs?

Car Analogy

In my consulting practice and WLAN training classes, I like to give the following analogy concerning the design of WLANs.

While working with a vendor in the auto industry in Detroit, I was frustrated by their lack of understanding of why their WLAN, which was originally designed for data and was currently working well, was failing so miserably as a VoWiFi network. My explanation led to the following analogy:

You are an automobile designer, and your boss comes to you and asks for a new vehicle design. A vehicle is defined as a system of wheels/tires, engine/transmission, seats, frame, and chassis. They have asked for a vehicle that can carry two adults, travel at freeway speeds, and carry a 2200 lb payload. You might answer, “That’s easy. I’ll build you a truck!” The truck would meet all their design specs, and everyone would be happy.

If, at a later time, your boss asks you to design a vehicle that can do 0—60 mph in less than 5 seconds, with great cornering characteristics and a very low drag coefficient, then you would likely design a small, lightweight, high-powered, sports car. All would certainly be pleased.

Finally your boss requests a vehicle that can comfortably carry seven adults with their luggage, has lots of cup holders, and allows easy entry. You would likely design them a mini-van. Again, all would be pleased.

The problem surfaces when the truck owner thinks to himself, ‘Since my truck is a vehicle, it should go from 0-60 mph in 4.2 seconds.’ Almost as an afterthought the truck owner asks you to make his truck become a fast sports car.

Sure, it’s possible, but at a significant cost. You could take out the old engine and replace it with a much stronger one, but since the truck was originally designed for carrying a heavy payload, it is built with a heavy suspension and dual-I-beam construction. In order to get it to have a fast race time, you’d also have to replace many of the ‘guts’ with carbon fiber composite parts!

Even after all that work, it would no longer be a good truck, nor a fast sportscar.

Certified Magazine Readers

Sometimes our bosses are like the bosses in the above vehicle analogy. They have read something in a magazine about WLANs doing Voice over IP, Video, or even Location Tracking. They come to the IT folks asking to simply ‘add’ this feature to the existing WLAN infrastructure.

Many of the design characteristics of these newly requested services require, indeed demand, mutually exclusive design goals!

For example, the VoWiFi WLAN might be the sports car design since it doesn’t carry a lot of payload. Yet the VoWiFi network needs to have very high tolerance and characteristics for the small set of data it does carry.

For example, VoWiFi vendors define the following detailed specifications:

• Minimum RSSI >= -65dBm
• Backup/Second AP at >= -65dBm
• Signal to Noise Ratio > 19dBm
• Maximum Noise Floor < -90dBm
• Maximum Jitter <5 msec
• Maximum Latency <50 msec
• Maximum Packet Loss <1%
• Total End to End Delivery <150 msec
• DTIM Interval 2
• Channel Overlap 25%
• Roaming Time <50 msec
• Required Data Rate 1Mbs
• Co Channel Separation > 19dBm
• Roam to 2nd AP if >= 5dBm higher
• Roam back to 1st AP if >= 10dBm higher
• 802.11e QoS Required
• Fast Roaming Required
• Multicast Enabled Required
• Specific Codec Required
• Maximum Calls per AP <= 7
• And even more…

Obviously the minimum RSSI in dB must be met, but note all the other detail specifications that also must be met.

Designing networks with just dB in mind will no longer work!

Web Surfing and large file transfers are more concerned with the size of the ‘pipe’ and can easily live with retries and temporary changes in the quality of the pipe. (the Truck)

RFID tagging and location tracking needs to have lots of access points in specific locations to support accurate triangulation, but those extra APs can cause more co-channel interference and make larger collision domains, thus lowering throughput. (the Mini Van)

Just because your boss read in a magazine about another company’s fast sports car, doesn’t mean your company’s truck will be a good vehicle to use in drag racing!

Know Your Design Requirements

My clients constantly amaze me when I ask them to specify (list) the design requirements of their WLAN devices. They rarely know what the design characteristics are for their own devices!

I ask you: If you don’t know what you are designing your WLAN for, how can you know when you’ve achieved the proper WLAN design?

In the automobile industry, no designer would willingly take on the job of designing a ‘vehicle’ without first understanding the detailed characteristics that are being requested.

In the wired network world, no ‘cable-puller’ would start pulling barbed-wire to each desktop! Barbed wire will easily meet the ‘connectivity’ goal, but obviously not any of the other Cat6 specs!

Yet somehow in the wireless LAN world, we allow ourselves to do just that. We design our WLANs without specific design goals, we design for only ‘coverage’ (dB), and then we later wonder why the WLAN doesn’t work…

If you don’t know the specific design parameters your client stations require, your WLAN can NEVER meet those goals!

Conclusions

Yes, Yes, Yes, and Yes… dB is VERY IMPORTANT! But it is NOT the ONLY goal around which you should be designing.

You don’t design wired networks with ‘barbed-wire’; so don’t design your WLANs with ONLY dB!

Additional Articles for Supporting WLAN Site Surveys
- 7 Rules for Accurate Site Surveys
- How to ‘Cheat’ On A Survey – Don’t be a Victim
- How to Properly Analyze Survey Data
- The Fallacy of Channel Overlap
- Predictive Survey vs Onsite Survey – What’s the Big Deal?
- How to ‘Spec’ your Network’s Physical Layer
- Want, Don’t Want, Don’t Care – Meeting Design Specs
- The Truth about SNR – Where Did that ‘N’ Come From Anyway?
- What is an Access Point Anyway – Hub, Bridge, Switch or Router?
- Passive vs Active – What’s All the Fuss About
- The False God of dB
- Meeting All Device Design Parameters

http://wlaniconoclast.blogspot.com

Wifilink

HyperLink

MoonBlink

Netgate

Pasadena Networks

PCTEL, Inc.

WiFi Antennas|| RadioLabs

WLANMall.com

WLANAntennas.com

And I must agree, many times we are too caught up in our own politics, technology, sports, and entertainment that we ignore some of the best the world has to offer. Many US citizens don’t have a clue about the rest of the world.

We need to be better World Citizens – better ‘learners’ of World situations – better understanding of how ‘the rest of the world’ thinks and operates!

I can’t believe we are still using inches, feet, pounds, miles, etc. instead of the World standard of Metric. I remember decades ago in school when we were on the ‘road to metric’… yeah right… that’s sure come a long way.

But in our favor… a couple of graphics that show some of the US-Centricity is to be expected. First is a graphic of phone call traffic… kind of obvious that one is. Remember, we are NOT the largest, nor most populated…
The second based on Internet traffic. The colors represent volume of traffic.
These were both found at the following web site. http://www.telegeography.com/maps/index.php

OK, before you ‘freak’ and think that I’ve lost my mind… just hold on a minute and read the rest of the article. This is the smallest, lightest, and ‘funnest’ WLAN test kit out there.

For doing a lot of smaller, quicker WLAN troubleshooting, this is a suitable solution. In addition, you get all the benefits of having an Apple iPod – with music, podcasts, videos, and games available as well as the Network Troubleshooting Tools!

I picked up an Apple iPod Touch (I always want to call it an iTouch) – at the local Costco, sync’d it to my laptop’s iTunes and had a working troubleshooting and support tool within mere minutes. In addition to the WLAN and Network tools, I use this as an ‘end-point’ to test VoIP calls when doing AirMagnet VoFi Surveys. With an attached headset with microphone this makes an excellent VoFi Phone as well. (both for standard SIP as well as SKYPE calls)
So what more could you ask for in a small light-weight device?

• WLAN troubleshooting
• Network Troubleshooting
• VoIP over WLAN Calls
• File sharing over WiFi
• Repository of Technical PDFs, White Papers, Docs
  
• Music, Podcasts, Videos & Games
• And it can easily be charged by any USB port!

Here is the parts that I use for this kit

1. Apple iPod Touch – 8GB $214
2. Stereo Headset with Mic $9
3. Free SIP Service $0
4. Apple iTunes $0
5. WiFiFoFum $3
6. WiFiTrack $1
7. Network Utility $1
8. iNetInfo $2
9. Bytes $1
10. GPS Utility $1
11. Network Ping $4
12. iNet $2
13. Skype $0
14. SIP Phone $7
15. AirSharing $5
    
16. WiFi Sharing $6
    

Total Outlay $256

You can easily go up to a 32GB device – just add a bit more money. With the extra space you could hold lots of PDFs (support documents) or Movies if you are so inclined.

Here’s some photos and specs on the little guy – cute, lightweight, small and yet powerful and FUN!
Below is a list of the Apps I use on my iPhone/iPod Touch to help me work on Wireless LANs.

WiFiFoFum a quick easy way to see the local WLANs with channel, signal strength and security. It also has one of those ‘weird’ radar views – totally useless, it has no actual info on direction, only simple RSSI.
WiFiTrack Lists local WLANs by Open vs Locked. Includes Signal, Channel, and type of encryption, ie. WPA2/Radius… Clicking on an AP will also give you the MAC address and if the AP is broadcasting SSID. This one also allows you to connect to a new AP directly from the App.
Network Utility This is not a WiFi specific tool, but it does allow you to Ping, Scan IP Ports, GeoIP Lookup, Whois Query. In addition, you can use it to find your Internal and External IP Addresses.
iNetInfo A quick way to see your IP Address, Hostname, MAC, Default Gateway, DNS. Network Ping A ‘super-ping’ that can not only do simple Ping tests, but ping-sweep a subnet, traceroute and Telnet.
iNet A network scanner that can give you quick simple information on your network, including Bonjour services and devices. It also has a great deal of detail for individual devices on your subnet.This one will scan your local subnet and report on all the devices it can ‘see’. Not just the APs, but all the clients on your subnet. Clicking on a seen device give you it’s IP, MAC, OUI and if it answers a PING. You can then do a scan for supported services on that specific device. Kind of fun to use to see what is OPEN around you.
Bytes A binary calculator with a great set of tools for doing a variety of binary and bit-level manipulation on top of Unit conversion and a quick reference for 2 to the x power results.
GPS Utility I use this tool to convert Lat/Long specs from Minutes/Seconds to decimal. (AirMagnet Survey using an outdoor GPS survey needs decimal, and most mapping software uses minutes/seconds)
Skype - Yes, just like your big computer, your little iPod Touch/iPhone can now run Skype via a WiFi connection. Voice calls, Chats, etc. – available from your small WLAN Troubleshooting device!
SIP Phone I use this tool to keep a live SIP call going while doing an AirMagnet VoFi Survey. It is also a great little test tool for connecting and tracking VoFi calls when doing troubleshooting of LANs. As your iPod Touch/iPhone roams, the calls can attempt to stay connected, and with your network packet analyzer you can track these packets to help in your troubleshooting issues.AirSharing I use this tool ‘host’ a file sharing session. I can share saved/archived documents on the iPod Touch/iPhone to share with clients, contacts, students, etc. Support documents are great to have available in an instant.Connects with Mac, Windows, Linux or just any Browser.
WiFi File Sharing Like the above tool, this software lets me share files, maintain a locally accessable archive of technical documents, and have it all easily shared via WiFi to any browser. This also lets me view PDF, Excel, Word, PowerPoint, etc. directly on the iPod Touch/iPhone.
Anyone else find some other useful App to add to my iPhone?

What’s Your Favorite App?
Please comment, I’m always looking for better tools!

An overview on standards under the IEEE 802.11 (Wi-Fi) umbrella (as of Mar 09)

^#Excerpted from http://www.ieee802.org/11/QuickGuide_IEEE_802_WG_and_Activities.htm)

• 2GB RAM
• Intel Atom 1.6GHz CPU
• 64GB SSD (Solid State Drive)
• Glossy 8.9 inch LED display (1024 pixels x 600 pixels)
• 802.11g WiFi Card
• 10/100 Ethernet
• Bluetooth
• 3 – USB 2.0 Ports
• Built-in Webcam
• Ubuntu 8.04 OS
• Only 2.3 lbs

I got the extra RAM and big SSD drive so this would be fast enough and have enough HD space to be useful as a ‘DVD Player’ as well as do most of the things I do with my larger Macbook 13″.

Following the directions and processes from this web site – I was able to use a couple of USB drives to copy, install, and then configure this to work just like my Macbook.

I’m pretty proud of myself in getting a totally different OS loaded on this Dell. It works great!

OK – now for the things that I miss.

1. the keyboard is a bit cramped and the ‘ key is in a weird place.
2. two finger right click – doesn’t work, so I have to go back to the right clicker, or use the CTRL Click
3. two finger scrolling – not available (bummer)
4. Screen is only 1024 x 600…
   

Sometimes when screens need more vertical screen-space, I use a program called ‘Scale Resolution’ to go to a 80% view, but that is very seldom. Additionally I use a Bluetooth mouse and all’s good.

I highly recommend this – go get one!

OK, I understand the word ‘Cheat’ is a pejorative, and connotes some sort of blatant attempt to break some rules or misrepresent. Many individuals just didn’t know any better when they applied these methods in their survey reporting. I’m not implying that these techniques suggest any malfeasance, only ignorance.

As a customer, the best protection against this type of deception is to request not only the paper or PDF report, but the actual data files so you can review and analyze the data directly yourself.

Below are some of the techniques that allow one to modify and present survey data to reflect whatever you might desire.

Be wary of using any of these techniques on your own analysis or in reviewing data presented by other third parties.

Method 1 – Incorrect Signal Propagation Value

One of the easiest ways to save money and time in the data-gathering phase of an RF site survey is to minimize the number of actual data points collected.

It is possible to use site survey software to interpolate a small number of data points and produce a complete ‘Heat Map’ of an entire building. The software and algorithms will usually allow for this. Just because the software can try and compensate for a poorly conducted survey doesn’t mean you should accept it.

A telltale sign this is being done is to look at the outside ‘arc’ of coverage. A tight Signal Propagation Assessment (SPA) value will have a tight arc, a large SPA or ‘guess range’ will have a very wide, almost flat, arc. Of course, if you have the actual survey data, you can see what the Signal Propagation Assessment value is set to.

This technique is used to ‘mask’ a survey with not enough data points and/or a survey that is showing ‘white’ areas on the floor plan. White does not mean there isn’t RF coverage; it just means there isn’t any data to support the heat map ‘painter’ to color that area.

I suggest you always go with an SPA no larger than that suggested by the survey application’s default values for the type of building you are surveying.

Method 2 – Using ‘Auto Contrast’

When configuring AirMagnet Survey, as an example of a site survey application, you can set the color adjustment to a variety of color palettes. Some of these are easier to see than others.

Note: Some persons with color-blindness have a hard time with the ‘smooth’ color gradients. There is one specific color option that is easier for them to see. But I find this very difficult for me to interpret because of the high-contrast changes.

One of the options in the Color Configuration is to set the ‘Auto Contrast Adjustment’ checkbox. Normally, the top of the color bar is always the same color, and the bottom is always its same color. Thus the middle is also always the same color. Thus a -65dBm is always represented by the same color on screen and in reports.

If you turn on ‘Auto Contrast Adjustment’ the top and bottom colors ‘move’ as you raise or lower the limits. Thus you can make -65dBm appear as any color you’d like.

This is a nice ‘feature’ is you already have a color palette and expectation; you can make AirMagnet Survey match to your expectations. But, in the wrong hands this one tool allows one to make any survey look good or bad. Any color can mean any dB!

The telltale sign this is being used is when the bottom of the color palette, like red for example is NOT showing for -100dB, something higher on the scale.

I have seen some companies actually use this technique to ‘standardize’ their reports so the same colors always mean the same dBm. Unless you are closely attuned to their legend, you’ll be misled on the signal strengths.

I recommend locking on a single color palette, turning off Auto Contrast Adjustment and having consistent universal colors on all your surveys. Green will always mean the same thing; Blue always the same, etc.

Method 3 – Use of ‘Banded’ Color Schemes

Another one of the many Color options typically available is ‘banded colors’. The use of this color option is sometimes applied to show what is ‘acceptable’ or not. Above a certain color band is approved, and below is unacceptable.

The problem with this technique is that there is often only a single dB difference between the color bands. So the strong, high-contrast line between acceptable and unacceptable is only 1 dB… This mis-represents the actual data and how close the subtle changes in RF are.

Smooth color palettes represent these slight changes in RF in a more representative fashion.

Method 4 – Access Points Where No Data Exists

Site survey software and algorithms often compensate for a poorly collected survey by generating ‘phantom’ data based on where an end-user ‘places’ and access point on the survey screen.

It is easy and possible for accidents to take place and an access point is placed not where it is in real life, but where you’d like it to be. Or the opposite, one can place an access point where it is in the real world, but not have any data collection points near that location.

In either case, the calculated and interpolated data is manipulated by the site survey software to generate RF data to support in placement location and power setting of the Access Point in question.

If your data collection is accurate and has followed all of the survey rules, there should be no need to process the data with this access point placement. If you do need the graphic of the access point on the screen, just place it without processing the data. (Display Only) When used incorrectly, the results show much stronger signals around the access point than were actually collected during the survey.

Note: If you show the resulting screen with placed-and-processed access points using the 3D display option you’ll easily see these ‘phantom’ results. I call it the ‘Circus Tent Syndrome’ – each access point has a little volcano looking mountain directly around its center point.

If there are no data capture points (red dots or blue dots) near an access point, but it shows very strong signal, then someone has mis-used this feature.

Method 5 – One-Sided Guesses

No ‘One Way Guesses’. This happens when you don’t capture on both sides of what you care about. If you take one data capture point on the inside perimeter of your building, and don’t also take one on the outside, then the site survey application doesn’t know anything about the ‘thickness’ (in RF Attenuation) of the exterior wall. It ‘learns’ this by having data captures on both sides of the wall.

If your survey was more ‘inside out’ the data processing algorithms must assume there is no walls, and uses a free-space-loss calculation. In the absence of better data (both sides of what you care about) – free-space-loss is all the software has to go on.

If you look at your survey results and there is heat map information, but you can see a wall between where the data point was collected, and a location where you ‘care’ – the resulting heat map will be incorrect.

Method 6 – Not Enough Data Points

This is usually the sign of a ‘lazy’ survey. Not only does the fact there is not enough data points lower the accuracy of the survey, more importantly it usually also comes with an increase in the Signal Propagation Assessment value to offset the lack of data to start with.

If the SPA is set to 5m, then there needs to be a red dot or a blue dot every 5m. Simple. More dots is fine, but fewer dots than your SPA will result in white spaces showing up on the floor plan. Then you might be tempted to increase the SPA in order to ‘hide’ these white spots.

Method 7 – Un-calibrated Survey

When you start a new site survey project, you are given the option to enter the drawing’s dimensions (not the building’s dimensions, but the drawing’s dimensions). If you leave it blank, (normal) some survey applications, such as AirMagnet Survey, will calibrate your drawing to a square 120’ x 120’. This will be your telltale sign you have NOT calibrated yet.

Calibration should be the first thing you do after starting a new project. If you forget, and go about your survey collecting data – it is very difficult, if not impossible to accurately adjust all the data to the new calibration after the fact. So, if you see a 120’ x 120’ in the site dimensions you have a survey that is un-calibrated!

In AirMagnet Survey in particular, above the upper right corner of your drawing there is a little dimension line. This is NOT the dimension line of your building, but what AirMagnet is using. Just because you have one there does not mean your drawing is calibrated.

Also, if you ever see a floor plan that looks a bit ‘off’ – like the X or Y axis is skewed – this is also a telltale sign you have an un-calibrated drawing.

Method 8 – PDF or JPEG Only

As a customer, you should request the PDF report, possibly the survey graphics in JPG format, but most importantly are the actual survey files. This way you can do your own analysis.

Another means of mis-representation is to not include the walking paths and data collection points. This, coupled with a high SPA (Guess Range), can be a sign the presented survey data is far too optimistic.

To properly analyze the survey data, you need to know where the data was collected and what data has been interpolated.

Don’t settle for just a report; require the data files along with the reports.

Method 9 – Showing Only the Results for a Single SSID

When analyzing survey data, it is very sometimes appropriate to include ONLY a specific SSID in the data set. In fact, this is the preferred method when analyzing for a (STA’s) device’s specific design requirements.

But, when doing analysis on interference (collision domains), ALL RF signals and access points should be included. These ‘other’ devices still have an effect on the collision domains of ‘your’ access points and clients (STAs).

The subset of collected data you are analyzing is important. Sometimes you need to look at ALL the data, and other times just the SSIDs you care about.

Conclusions

Whether it’s on purpose, or merely an oversight, the use of any of these aforementioned methods may present site survey data in an inaccurate light.

Be forewarned and prepared to make an accurate evaluation of the survey data presented to you.

If you are the one presenting Survey Data… be sure to take an accurate survey (following all seven rules) and don’t use any of the above techniques. You don’t want to be a ‘cheater’ do you?

Again another adage; Just because the software allows you to manipulate the presentation of the data doesn’t mean you should!

Additional Articles for Supporting WLAN Site Surveys
- 7 Rules for Accurate Site Surveys
- How to ‘Cheat’ On A Survey – Don’t be a Victim
- How to Properly Analyze Survey Data
- The Fallacy of Channel Overlap
- Predictive Survey vs Onsite Survey – What’s the Big Deal?
- How to ‘Spec’ your Network’s Physical Layer
- Want, Don’t Want, Don’t Care – Meeting Design Specs
- The Truth about SNR – Where Did that ‘N’ Come From Anyway?
- What is an Access Point Anyway – Hub, Bridge, Switch or Router?
- Passive vs Active – What’s All the Fuss About
- The False God of dB
- Meeting All Device Design Parameters

If you can not measure it… then don’t use it in your design spec!

Someone telling you, “I’ll know it when I see it” just isn’t good enough. We need to be able to PROVE or VERIFY that our wireless networks meet a design specification.

Calculating Overlap

Might I suggest that no one has calculated this ‘overlap’ properly? I, for one, don’t have the math skills necessary to do it properly.

Here’s an example (we’ll start out with an easy one)

This picture is obviously represents 0% overlap or no overlap at all.

Ok, now for a bit harder…

What is the overlap here?

Don’t jump right to your foregone conclusion… Let’s think about it first…

This is:

50% overlap of Diameter

100% overlap of Radius

29% overlap of Circumference

23% overlap of Area

The calculation to get the Diameter and Radius were pretty much brain-dead easy… but the other two, not so much…

Here’s just the example for the calculation of area when two circles intersect.

With the following associated formula:

Getting to Reality

Are telling me you do this calculation for each and every access point where it intersects with another one of your access points in your WLAN designs? I think not.

Not to mention, access points radiation patterns are never ‘really’ circles but normally look more like amoebas or starburst type patterns… do you even know how to start calculating those areas’ overlap?

So again, If you can’t measure it, then don’t include it in your design specs!

What you CAN calculate, and SHOULD be using, is the effect of overlap on individual clients. You can use this calculation to ‘prove’ or ‘verify’ that your WLAN design is meeting the actual design spec of your specific STA (device).

In AirMagnet Survey, this is found in AirWise and set the requirement for 2 access points at say -67dBm.

It’s pretty easy really. The reason we have this ‘overlap’ thing is to make sure the STA’s have adequate duplicate coverage. In other words, each STA needs to see at least one access point at a specific RSSI, and a ‘backup’ or secondary access point at a different RSSI.

Some vendors spec the same for both the primary and secondary – like some VoIP phones want to see a primary at -67dBm and a secondary also at -67dBm – or in other words – two at -67dBm.

Now this we can easily measure!

Just complete a passive survey with your favorite tool of choice and ask the system to show where in your network coverage areas you see TWO access points with a signal greater than -67dBm.

No more trying to guess on percent overlaps, no more making up some ‘eyeball’ answer. Just a plain and simple answer to the question –

Do I have adequate coverage to meet the design specifications of my client (STA) devices?

By the way – you’ll need to do a survey following all the rules of proper surveying. Of course, you always follow the rules, right?

Conclusions

Don’t pretend to be able to calculate access point coverage overlaps using a graphic based on area. Look at this from the client’s point of view, and make sure you have the correct RF everywhere to meet the ‘backup’ needs of the clients.

Additional Articles for Supporting WLAN Site Surveys
- 7 Rules for Accurate Site Surveys
- How to ‘Cheat’ On A Survey – Don’t be a Victim
- How to Properly Analyze Survey Data
- The Fallacy of Channel Overlap
- Predictive Survey vs Onsite Survey – What’s the Big Deal?
- How to ‘Spec’ your Network’s Physical Layer
- Want, Don’t Want, Don’t Care – Meeting Design Specs
- The Truth about SNR – Where Did that ‘N’ Come From Anyway?
- What is an Access Point Anyway – Hub, Bridge, Switch or Router?
- Passive vs Active – What’s All the Fuss About?
- The False God of dB
- Meeting All Device Design Parameters

The process of gathering appropriate and accurate data during a Site Survey is as simple as following a few easy rules.

Break the rules, however, and you could end up with totally useless – but colorful – Heat Maps that have no value to your organization.

These rules have been gleaned through hundreds of site surveys and through teaching over hundreds networking professionals how to use Site Survey products.

Rule 1 – Calibrate Your Drawing Properly

Setting the underlying ‘grid’ is critical. If you don’t accurately calibrate the drawing to reflect the reality of the actual building, with the drawing on your screen – all your data will be virtually worthless. This is #1 in the list because it is the most important step, and you should always do it correctly as soon as you open a new project.

Do not use a doorway as your ‘baseline’ to calibrate from. Use a longer dimension, as long as you can measure. I use a Laser measuring device that works out to 50m or so. Measuring wheels, long tape measures, laser, or sonar all work; just try to find the longest edge. You only need to have one dimension to accurately calibrate a drawing that comes to you with the correct aspect ratio.

Better yet, have the CAD folks drop a Dimension Line underneath the actual building on the drawing to give you an even more accurate line to calibrate against.

Note: While we’re on the subject of the drawing, simplify your drawings as much as possible, using only black and white. ‘Flatten’ the drawing down to just the simple floor plan, no need for furniture, plants, where the jacks are located. Just simple black on white walls in your drawing is best

Rule 2 – Set the Channel Scan to the Correct Frequencies

Scan ONLY the channels you want, and don’t scan the channels you don’t want. This sounds simple… but making a mistake here can cost you greatly in the accuracy of the post survey data. If you ‘accidentally’ set it to scan ALL channels (over 200 are available to scan) – even at only 250 ms each (1/4 second) the system will nearly a minute of time to return back to the starting channel. (and you can walk quite a long way in a minute!)

I recommend setting the scan channels to the 11 (or 13) base 2.4 GHz channels and the 5 GHz channels for your regulatory domain (in the US this can be the 4 Indoor Only, plus the 4 Indoor or outdoor channels) and do a passive survey of the outside perimeter of your building first.

This will give you a nice capture of your neighbors, as well as your ‘leaking’ RF. But better yet – it will give you a nice set of channels to concentrate on when moving indoors to do the real Site Surveys.

Perhaps even do two survey walks, one for 2.4 GHz and one for 5 GHz channels. That, or watch the bottom left corner of your survey screen and don’t move to the next data capture point until the channel scan marker returns back to ‘1’.

Scan what you want, and don’t scan what you don’t want!

Rule 3 – Set Your Guess Range Properly

This goes by the more professional term ‘Signal Propagation Assessment’ – but it basically means how far do you want your Site Survey application to ‘guess’ (Interpolate) in between your captured data points.

A really accurate survey would set this down to one meter. But the problem there would be that you’d have to go and click on every single meter of space in your building. Accurate yes, but practical, no.

Or the opposite, go to the center of your building and take a single data snapshot… then set the Guess Range to 50 meters… This one is easy and quick, but not accurate at all.

Reality is somewhere in between. Most survey applications have a couple of pre-defined options for you. You do not have to use these pre-defined Signal Propagation Assessment (SPA) numbers. Use what you think appropriate for your site; the smaller the better. It will force you to take more data points and thus get more accuracy.

For most indoor buildings, I like about a 5m Signal Propagation Assessment value.

Rule 4 – Set Appropriate ‘Snap Rate’ For Your Situation

The automatic snap rate is based on a time. You set the number of seconds when your survey application will take an extra ‘snapshot’ of your RF information. Too fast and you’ll get ‘blue lines’ with too much information and slow down your processing. Too few and your snaps will be too spread out. (Think of Goldilocks… just right…)

If you are doing a Manual (red-dot-only) survey – be sure to take a snapshot no further than what your SPA is set to. So if you set your ‘Guess Range’ or SPA at 5m, you must take a snapshot (click) at least every 5m.

Rule 5 – Capture on Both Sides of What You Care About

No ‘One Way Guesses’. This happens when you don’t capture on both sides of what you care about. If you take one data capture point on the inside perimeter of your building, and don’t also take one on the outside, then your survey application won’t know anything about the ‘thickness’ (in RF Attenuation) of the exterior wall. It ‘learns’ this by having data captures on both sides of the wall.

If you don’t care about the RF leaking outside, then this is fine. But if you do care about some area, whether it is inside or outside, you must do data captures on both sides.

Thus another corollary to this rule – Capture Outside In, Not Inside Out. Capture on the perimeters of the rooms you want to prove coverage – not one single shot from the center of each room.

One additional part to this rule; If you have ‘special’ places you need to be real sure about – then take extra data captures at those locations, ie. CEO’s desk, Board Room, etc.

Rule 6 – Click Accurately

You don’t actually walk through walls, walk on water, or fly when you are doing a Site Survey – don’t have your data look like you did or your credibility will be shot.

Prepare your walking paths in advance. You might even put little numbers on your drawing before you import it with the locations where you want to click (capture data) – and then you’ll just have to play ‘connect the dots’ with your feet later during the survey.

The old adage, Fail to Plan means Plan to Fail… holds true in this respect. I’ve seen many people who get lost, or get stuck down the end of a hallway and don’t seem to know what to do with the Survey, or where to go next. Preparation is key on this point.

If you can’t easily find yourself on the floor plan – it is a skill that can be practiced you know – then work on it until you are comfortable moving around in three-dimensional space.

When you are doing an AirMagnet Survey ‘manual’ survey, with red dots only, the dots are connected with dashed lines. These dashed lines, without blue dots, can go through walls, walk on water, and fly… it’s the autosnap blue dots we worry about.

Note: Here’s a trick to use while doing a survey. While standing still at the end of one data capture point, place your mouse cursor at the next place you plan on stopping, then start walking. When you arrive at the designated point, you only need to ‘click’ and the data point is collected right under where the cursor was waiting.

Anytime you can see a specific marking on a blueprint or floor plan, add a click for accuracy. Of course, you could walk the entire hall and your survey application would place all the data points as soon as you finished the length of the hall. But accuracy improves as you have accurate intermediate click points.

If you don’t go to all the locations and click accurately, you’ll be tempted to increase your SPA to ‘fill in’ the missing data points. (no one likes to see white spots on their heat maps).

Rule 7 – Always, Always Do A Passive Survey

You might have a reason to also do an Active Survey, (see Passive vs. Active Surveys article) but you ALWAYS must do a Passive Survey on the entire building you care about. I’d also recommend doing a Passive Survey on the exterior of the building as well.

A Passive Survey can give you information on your neighbors, others, and all of your own devices.

This is especially important for determining RF interference. If you don’t have neighbor information in your Active Survey, you can easily miss the interference on specific frequencies. Additionally, this can show you where your ‘collision domains’ are.

In addition to these rules that pertain to Passive Surveys, Active Surveys have some rules of their own.

Additional Rules for Active Surveys

Capture Data from ALL Access Points
It is quite easy to do an active survey and only get data on a subset of your Access Points. You can merge this with a Passive Survey data set and end up with what looks like an accurate survey, but it is NOT. You need to have ALL Access Points included in your Active Survey for accurate representation of your RF WLAN environment.

Capture To The Edge
When capturing Active Survey data from an Access Point, it is easy to not go to the edge of the coverage area… it’s so far to walk – so we might stop as soon as we can see the coverage meets some design goal, like -65dBm. But this is where the failure lies. The easiest requirement to design for a WLAN is RF Coverage, but it is only the first of many requirements (see False God of dB article). The hard thing to deal with is the interference, and you’ll only learn about this if you capture data to the edge of each Access Point’s coverage area. (yes, I know this is hard and expensive to do!)

Do NOT Set Roaming To Be Too Aggressive
I understand you may have the great power to over-ride the WLAN NIC’s roaming decision process with your survey application’s roaming options feature. This makes surveying much faster and easier. Don’t succumb to the temptation! If you set the Roaming Option to only connect at 54, 48, and 36 data rates, then your data will only show 54, 48, and 36 data rates. Since you didn’t capture the other data rate information, your report won’t show it to you.

In reality, your client cards will roam according to their own algorithms and will downgrade to whatever data rates are supported in the Access Points.

And another adage that should always be remembered with respect to wireless LANs – just because you can, doesn’t mean that you should.

De-Skew Data In Sticky Situations
Sometimes when taking an Active Survey the data gets a bit ‘skewed’ in the direction of travel: away from the access points. If this is the case you’ll need to do two Active Surveys for each access point, one clock-wise and one counter-clockwise and then merge those together to ‘de-skew’ the stickiness.

Merge All Actives Before Merging With Passive
Just like it says.

If You Don’t Do Active Surveys Right – Don’t Do Active Surveys At All
If you do Active Surveys wrong, you’ll end up with a less-accurate and ‘worse’ data set than not doing any Actives at all.

Conclusions

Obey these rules or else… Or else the data you capture will be suspect at best, and totally useless at worst.

Also – don’t let your sub-contractors break the rules or ‘cheat’ on you either. Check out the How to ‘Cheat’ Using Survey – Don’t be a Victim article.

Additional Articles for Supporting WLAN Site Surveys
- 7 Rules for Accurate Site Surveys
- How to ‘Cheat’ On A Survey – Don’t be a Victim
- How to Properly Analyze Survey Data
- The Fallacy of Channel Overlap
- Predictive Survey vs. Onsite Survey – What’s the Big Deal?
- How to ‘Spec’ your Network’s Physical Layer
- Want, Don’t Want, Don’t Care – Meeting Design Specs
- The Truth about SNR – Where Did that ‘N’ Come From Anyway?
- What is an Access Point Anyway – Hub, Bridge, Switch or Router?
- Passive vs. Active – What’s All the Fuss About
- The False God of dB
- Meeting All Device Design Parameters

i⋅con⋅o⋅clast

I could go on an on about how this little device has changed how we access the Internet in our home. Instead of lugging around laptops, we have a couple of N800s that the kids access for Internet queries, (just what High School did ‘King James’ go to – while watching the playoffs), to googling, to streaming music, conducting mulit-user IM sessions, to just about anything you’d want to use the Internet for – but in a very small package.

The screen resolution is amazing! If the iPhone has this screen, I’ll be in line to buy one. Even though I’m so old now I have to use bi-focals to read the small stuff – I’m comfortable with the N800’s little screen – the resolution makes it possible to fit so much in a little package.

But for the interest of this Blog I’ll move on to the use of the N800 in a wireless analysis mode.

I saw an announcement for a new piece of wireless security gear – called a Silica. This software/hardware bundle puts the intelligent penetration attacks and exploits of Immunity’s Canvas software in a small Nokia. It looked WAY COOL and I *wanted* to have one. But the $3,600 cost felt a bit prohibitive.

I’ve since had a chance to play with a Silica – and was suitably impressed – I still haven’t parted with the $3,600 but here’s a bit of a review of the tool.

This is a customized version of the Canvas tool – shoehorned into this small form-factor Linux device (Nokia N800) It is VERY easy to use. Just turn it on and click the start scan…

It will run through a series of scans of the local wireless networks, then attempt to penetrate using a variety of currently known exploits to find and exploit holes in your wireless LAN. It’s like having a little team of hackers sitting in you hand.

I’ve found it to be easy to run with the Nokia in your pocket. Very unobtrusive! – but in reality it takes up to 20-25 minutes to do a full attack against a single AP. Not like while doing a real penetration test you’ll have an excuse to ‘hang around’ a specific area waiting for the attack to finish. (Though you could easily hide the device and come back to pick it up later – but that $3,600 cost will probably make you think twice about leaving it outside of your view)

The reports it gives are in HTML format – you can just e-mail them to yourself, or copy them off onto the SD cards used by the N800

It does a pretty cool thing when attacking a MAC-Filtered AP – it automatically finds an associated STA and spoofs it MAC address to get associated.

It doesn’t do ANY WEP Cracking or WPA cracking, or anything but the exploits that are in Canvas.

Ok, now for the less expensive, yet still fun stuff using a Nokia N800. As part of our Wireless LAN Security Assessment Toolkit course development. We came across the N800s, fell in love with them, then re-arranged and re-wrote many of our course lab exercises to specifically use the N800s. We added wVoIP, video over IP, as well as catching IM traffic, web browsing, and other conversations sent over wireless to use the N800 as our client of choice when ‘watching’ the open Wireless LANs and re-constructing conversations via packet capture.

Then we thought, “is there anything more we can use the N800s for”?

Since the N800 is just a little Linux computer… we added SSH, Terminal Shell, VNC, FTP, etc. to the system. Then once we got that running, it was a quick couple of steps to get Kismet and Metasploit running!

So just using Open Source software we were able to take the little $400 Nokia N800 and make it ‘like’ a Silica!

Just slip this little ‘bad boy’ in your pocket running kismet and go WarWalking to get all the APs in your area, including finding ‘hidden’ SSIDs. Or, start Metasploit and let ‘r rip – attempting whatever known exploits are available for Metasploit.

(By the way – this is NOT a fast device for Metasploit – but Way Cool to have running)

On the other hand – it makes a great Kismet platform!

We’ve got ours running the classroom with GoogleTalk and Gizmo Project for wVoIP and IM – but you have to have a Wifi access to use it, so this wont’ take the place of your cell phone. (It is possible to pair this device via Bluetooth to a cell phone running G3 speeds – but the easy way is with Wifi)

Enjoy!

Keith Parsons – Managing Director

Institute for Network Professionals