Statements such as “…go from 20/40 to all 20 MHz and it have a 30% improvement” are highly dependent on the design of the infrastructure. If I walked into a university and they still had all of their WAPs in hallways, with clear line-of-sight to each other, then a statement like that seems plausible. It’s about the context, and without it, these statements can be misleading. And misleading to the point that people will accept it as absolute no matter what, potentially tossing a lot of their investment in a drawer.
In our environment, where construction is reinforced/filled concrete block, 5Ghz doesn’t propagate very far, and we’ve done much testing be it static 20MHz, static 40MHz, and DBS set to best at a max 80MHz, and the data absolutely shows a huge client benefit in DBS’s decision to run WAPs at 80MHz. But, we also place WAPs in rooms rather than hallways, and our client-base is almost exclusively 11ac. This is the “your mileage may very” portion of the disclaimer. We can certainly debate if that peak performance potential is necessary at this time, but again, the data indicates that there is client improvement. Jeff From: "wireless-lan@listserv.educause.edu" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> on behalf of GT Hill <g...@gthill.com> Reply-To: "wireless-lan@listserv.educause.edu" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Date: Friday, January 19, 2018 at 8:02 AM To: "wireless-lan@listserv.educause.edu" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: Re: [WIRELESS-LAN] Cisco Channel Width This is very anecdotal, but I have personally seen a large university go from 20/40 to all 20 MHz and it have a 30% improvement in end user performance. Everyone’s mileage will vary but given the data I’ve seen no way would I run 80 MHz channels except in VERY limited scenarios. If I were implementing a network today I would start at 20 MHz and move UP as scenarios presented themselves, NOT the other way around. GT From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> on behalf of "Jeffrey D. Sessler" <j...@scrippscollege.edu<mailto:j...@scrippscollege.edu>> Reply-To: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> Date: Friday, January 19, 2018 at 9:14 AM To: <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> Subject: Re: [WIRELESS-LAN] Cisco Channel Width Been running that option (Best) for a long time. No downside that I’ve found and after a few passes it’s very stable with channel width. Even in our dense AP deployment residential areas, most all of our WAPs are running at 80Mhz - our students having mostly 11ac devices. The bandwidth use in our residential went way up as a result. As to clients getting kicked off when the width changes, Cisco’s magic sauce tries to prevent this from happening (it’s detailed in the white papers). The code also makes decisions based on the client mix it sees e.g. if it sees a majority of 802.11n clients around a WAP, it won’t run that AP at 80Mhz. If the WAP is mostly 11ac, it will. Running a static 20Mhz plan, in my opinion, is just tossing away performance and client experience. You wouldn’t purchase an 800HP supercar only to permanently disable half of its cylinders. Jeff From: "wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> on behalf of Les Ridgley <les.ridg...@newcastle.edu.au<mailto:les.ridg...@newcastle.edu.au>> Reply-To: "wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> Date: Thursday, January 18, 2018 at 6:45 PM To: "wireless-lan@listserv.educause.edu<mailto:wireless-lan@listserv.educause.edu>" <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>> Subject: [WIRELESS-LAN] Cisco Channel Width Hi All, For those Cisco shops – has anyone configured the “BEST” parameter for channel width that would like to share their experiences or thoughts on the benefits or otherwise . We have been advised to use 20Mhz as a campus wide setting, however DBS appears to offer significant benefits that would allow us to make better use of our 802.11ac AP’s. We are currently running two 8540 WLC’s with around 2,500 access points with a mix of 3600 – 3700 -3800 and 1810 access points. Thanks in advance, Les -- Les Ridgley Senior Communications Officer (Network Operations), IT Services Resources Division The University of Newcastle University Drive, Callaghan NSW 2308 les.ridg...@newcastle.edu.au<mailto:les.ridg...@newcastle.edu.au>, Phone +61 2 4921 6598 Fax: +61 2 4921 6910 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
