With the 3 channel system rouges are less likely to cause issues I'd think. A rouge is likely to use 1 6 or 11 as that is the standard. If you have a 4 channel system a rouge is going to be a huge problem where it is only an annoyance in a 3 channel system. I have found that co-channel interference is not that big of a deal. The protocol still works if clients are connecting to different APs on the same channel. However adjacent channel interference is another matter. That ends up just being noise.
John Kaftan IT Infrastructure Manager Utica College 315.792.3102 From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[email protected]] On Behalf Of Hanset, Philippe C Sent: Tuesday, May 08, 2012 11:10 AM To: [email protected] Subject: Re: [WIRELESS-LAN] 4-channels in 2.4 GHz Lee, Univ. of TN Knoxville still runs 4 channels (1-4-8-11) and has been doing so since 2000! This said, we had a long discussion with Aruba Networks engineers about 3 VS 4 and they mentioned that their algorithms are better tuned for 3 channels (I suspect that it is the case for most vendors that provide managed APs). The reasoning is that an AP (or controller) can more easily detect and deal with co-channel interference than it can with adjacent channel interference (not as detectable). So, we have tested a dormitory with 3 channels, and are very pleased with the results. The throughput increased sightly, which is not a small thing. We plan to convert the whole campus to 3 channels. In the world of human managed APs it made more sense to us to have 4 channels. Easier graph coloring and we also measured a true benefit in high density environments. But we didn't change channels all the time and didn't play with power! In the world of managed APs, and if you don't plan to tweak settings from the manufacturer, I would say, stick with standards, in this case 3 channels, just because most of those systems are designed to do so. Sorry, no cool graphs with measured differences, just a discussion ;-) Best, Philippe Philippe Hanset Univ. of TN, Knoxville www.eduroamus.org On May 8, 2012, at 10:34 AM, Lee H Badman wrote: With no intent to open a conversational can 'o worms, I'm curious if anyone is running a 4-channel plan on their production WLANs, that is willing to share their opinions and experiences on the topic. Thanks- Lee Lee H. Badman Wireless/Network Engineer, ITS Adjunct Instructor, iSchool Syracuse University 315.443.3003 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
