Wi-Fi MisinformationBy CWNP On 01/27/2011 - 20 Comments
Warning: I may sound snobbish (bordering on judgmental) in this article. I subscribe to a local technology newsletter. The members meet once a month, so I get a monthly invite to the nerdfest with a description of the topic, the schedule, the sponsor, and the presenter. Most months they talk about switching fabrics or virtualization or WAN optimization or something else that is not really in my swing zone. But, perhaps twice a year, the topic of wireless rolls around, and I attend. Last night was one of those nights.
I’m not exactly mister technical socialite, so I don’t have a lot of techie friends around here (All my techie friends are online. Go figure.), so I go into these events as a sort of unknown and silent observer. I hope to learn something and I usually go in with high expectations that the presenter will knock my socks off and give me some handy technical tidbits or some tips for practical application. Much to my surprise, I spent most of last night shaking my head in disbelief…also biting my tongue.
Here are some of the things that I saw and heard (I didn’t take notes):
- MIMO Equalizer is the foundational technology that allows spatial multiplexing.
- STBC is the back-end engine that provides all MIMO functionality.
- There are 12 channels in the 5 GHz range.
- If you configure a radio’s channel for “40 Above,” this puts the 40 MHz bonded channel in the upper UNII band.
- OFDM (with 802.11g) overcomes the multipath problems experienced by 802.11b.
- Cisco beamforming chips use a 2x1 MIMO configuration.
- When DFS is disabled, for some reason, only 9 of the 12 channels are usable.
- The Wi-Fi Alliance ratified 802.11n in 2009.
- Transmit beamforming works by phasing.
- Some enterprise vendors don’t allow 40 MHz channel bonding in 5 GHz, which provides an advantage for Cisco.
- The FCC doesn’t like it when you use amplifiers because it is too hard to control the output power.
- There were many other explanations of MIMO, 802.11n, and radio dynamics that were a little too confusing to understand and repeat here.
I did provide a warning that I may sound a little moralistic or cranky, and I certainly don’t mean to sound like I know everything (after all, I was there expecting to learn). Nonetheless, I just couldn’t believe my ears. One part of me wanted to find out why he thought he should be teaching all of these people about these topics. He had to know that he didn’t really know this stuff...right!? On the other hand, I didn’t want to sound like some elevated, pedantic ass (like I probably do now) by correcting his every misstep, so I just decided to leave. I came home and told my wife all about it. In all seriousness, 30-50% of everything he said was inaccurate, and some of the rest was too confusing to evaluate.
To his benefit, I did hear some things that were right:
- TKIP and 802.11n rates don’t play well together with Cisco.
- Site surveying is important.
- Disable 802.11b rates when possible.
- Limit SSIDs. Use RADIUS attributes to assign user or group specific policies when possible.
I’m thankful for that, because I trust that he can probably deploy a network that works, though he may not understand all of the underlying technologies or proper configurations. On the other hand, I was really disappointed by the gross misinformation deposit that occurred. Based on the questions that were asked by audience members (probably around 60+ people) and the implicit acknowledgment that the presenter was an authority, it seemed pretty obvious that members of the audience lapped up the educational arsenic, completely oblivious. It’s sad for the resellers in attendance who may now feel confident and prepared to impress their customers, and it’s sad for the actual end users that think they now have a better grasp of how the technology works and how it should be deployed. I suppose I should clarify. It’s sad for resellers and end-users, but possibly great for competitors. :) I should probably also qualify that the presenter was an engineer of a reseller and not an employee of any vendor.
The whole point of retelling my experiences here is not to get down on him or the group or even to give CWNP or myself a pat on the back. I’ve learned what I know about Wi-Fi by spending time with generous people and by reading books, whitepapers, and standards that were written by people that know what they’re talking about. I owe a great deal of gratitude to others for where I’m at. The moral of my story is that there’s a lot of misinformation out there and that bad information could cost you or your company a lot of money.
I feel the need to add a marketing or sales tagline here. I think CWNP’s educational materials are pretty good, and most people would agree with that. If you read the blog, I’ll make that assumption. But, my sales pitch goes well beyond what CWNP can provide. Sure, read our materials (I think I have to say that), but also read industry whitepapers published by vendors, analysts, non-profit organizations. Read vendor user guides, design guides, and config guides, even if you don’t use that equipment. Read blogs. Watch videos. Get some hands-on and test the ideas. Validate what you think you know before spreading it like an STD.
I remember hearing a few years back about one of our CWSPs. Let’s call him Bob. Bob told CWNP that he got our certifications and read our study guides, but he doesn’t even implement his own WLAN. He hires it out to a consultant. But, Bob wanted to get the technical background simply for the purpose of vetting the consultants that he would hire. When a bozo walked in and couldn’t nail the technical details, he didn’t get the job. When a superstar came in, Bob would know, and the superstar would get the job, Bob’s network would be well designed and deployed, and everyone would be happy...except the bozo. That’s what education will do for you.
I have three primary takeaways from this story:
- Education will save you money, time, and headaches (except those caused by attending bad presentations).
- Bad education en masse = more job security for people that know what they’re talking about. This thought makes me feel all warm and happy inside.
- The market and need for Wi-Fi and RF education is big.