Blog

• CWNP
• October 27, 2009
• 

Understanding OFDM - Part 3

In Part 2 of this series, we determined the maximum baud rate for 802.11a/g, and calculated the maximum channel data rates by modulation type.  As an example, if using a BPSK modulation type  we arrive at raw channel data rate of 12 Mbps, for an 802.11a/g channel.  As a wireless LAN professional, you may be aware that the lowest data rate offered, in a pure OFDM 802.11a/g network, is 6 Mbps.  In order to understand the difference between the raw channel rate and the actual available channel rate, we need to see the effect that the forward error correction (FEC) mechanism used with 802.11 OFDM technologies, has on the transmitted information stream.

• CWNP
• October 23, 2009
• 

Wireless LAN Security and IEEE 802.11w

As Wireless LANs (WLANs) have been increasingly entrusted to carry mission critical enterprise data and voice communication, the impact of Wireless LAN (WLAN) Denial of Service (DoS) attacks has increased manyfold. The recently ratified 802.11w standard that provides Management Frame Protection (MFP) does provide some help in fighting WLAN DoS attacks. But, if you think that 802.11w can put an end to all of your WLAN DoS problems, I beg to differ. Please read on to find out why.

• CWNP
• October 14, 2009
• 

Pimpin [Wi-Fi] Ain't Easy

CWNP is on the road again, this time we’re mixing it up with Ruckus Wireless.  We’re out to save the world—several major US cities, at least—of boredom by offering some free Wi-Fi training, cool product demos, free food, handouts, and some wicked prize drawings.  If you don’t already know their corporate personality, Ruckus Wireless has what might be labeled “artistic moxie” when it comes to marketing and corporate culture.  They’re the antithesis of the stuffy, conventional, humorless corporation, which is just one of the reasons why they continue to succeed in Wi-Fi… it’s also why our roadshow is titled “Pimp My Wi-Fi.” 

• CWNP
• October 09, 2009
• 

Beam Me Up

On September 11, there was a flurry of excitement about the final ratification of the 802.11n amendment.  We were all glad that the seven years' war was over.  It seemed like the industry was excited to see this completion, but the crickets chirped after the first day or two of headlines.  Within the first few weeks, there have been some important developments, and the next few months should be exciting as well.  Here are a few pseudo-random thoughts on how Wi-Fi will change in the aftermath of the 802.11n-Draft era. 

• CWNP
• October 06, 2009
• 

Understanding OFDM - Part 2

In Part 1 of this “blogtorial”, Rick provides a high level comparison of the way OFDM is used in IEEE 802.11a/g.  In Part 2, he gives a more detailed description of OFDM subcarriers and the four modulation types used in Wi-Fi. Continue reading...

• CWNP
• October 06, 2009
• 

Understanding OFDM - Part 2

<p>In Part 1 of this “blogtorial”, Rick provides a high level comparison of the way OFDM is used in IEEE 802.11a/g.  In Part 2, he gives a more detailed description of OFDM subcarriers and the four modulation types used in Wi-Fi.</p>  

• CWNP
• September 23, 2009
• 

Understanding OFDM - Part 1

The 48-string Guitar

Like the sidewalk under your feet, always solid, never doubted, Orthogonal Frequency Division Multiplexing (OFDM) is the rock that supports current and near-term wireless technologies, including 802.11a, 802.11g, 802.11n, WiMAX, and LTE. As a wireless professional, you’ll be working with OFDM-based technologies for the foreseeable future. An understanding of OFDM will give you an edge in designing and maintaining the networks under your care.

• CWNP
• September 23, 2009
• 

Wireless Security: A Defense-in-Depth Approach for Wi-Fi Clients

Against those skilled in the attack, an enemy does not know where to defend. Against the experts in defence, the enemy does not know where to attack. – Art of War (Sun Tzu)

Two of my previous blog posts talked about defense-in-depth against Rogue APs and WLAN infrastructure-based attacks. We discussed that enterprises can achieve the best possible security by deploying a combination of wired solutions (e.g., 802.1X, NAC, Port security) and wireless solutions (e.g., WPA2, Wireless scanning, WIPS). The reason for this is that a combination of complementary security solutions provides better security than any of the individual solutions. This post talks about securing wireless clients.

• CWNP
• September 21, 2009
• 

The Hummingbird Sings a Song

A few weeks back, I provided a mild poke at Colubris for their apparent post-HP-acquisition silence.  Most vendors don’t turn up a big smile at such things, so it came as no surprise to me that Colubris was pleased to provide us with some details about their comings and goings since acquisition.  I’ll be the first to admit that I can’t read every press release—at least, not if I want to see my family—so I miss some of the good stuff.  Since my last article, I’ve found that Colubris has been doing some critical integration work with HP and they’ve released a few new products.  This is good news.  Added competition for the big players, innovation, and integration should all prove to be valuable.  Here’s the quick rundown of what I’ve learned.

• CWNP
• September 16, 2009
• 

Hot Off the Press: Arbitration Whitepaper

One of CWNP’s instructors and CWNEs, GT Hill, has what might be labeled a “fetish” with 802.11 arbitration.  Some people like shoes, others like gadgets, but GT likes teaching 802.11 arbitration.  He’s a Wi-Fi geek among the best of us.  ;)  If you get the chance, taking him up on the lesson would be a good use of your time.  If you don’t get the chance, the next best thing may be the 802.11 arbitration whitepaper that CWNP just published.