Jeff, Take in context that GT works for a company that builds a tool to quantify wireless problems based in depth packet analysis. So when he says he sees 35% improvement, there’s a lot of data that goes into it.
Sent from my iPhone > On Sep 26, 2017, at 12:41 PM, Jeffrey D. Sessler <[email protected]> > wrote: > > “After a switch to 20 MHz only, there was a 35% improvement in end-user Wi-Fi > experience.” > > I would argue that this is a meaningless statement without context, and > probably a bad question to ask a user in the first place. What does the user > think “experience” means i.e. the ability to connect or how well their > speedtest performs? It’s not specific enough to draw a conclusion. > > For example: > If 1/3 of my users had a device that could not associate because of how the > primary channel was selected in a 40 or 80 MHz wide deployment, then those > people would not be happy. If I then change to 20 MHz only, allowing those > users with the problematic device to connect, there will obviously be a > significant improvement in those user’s WiFi experience. The other users may > still be happy because they can still connect. > If my buildings are open-concept (no walls/doors), and I have 24 AP’s on a > 1000 sq/ft floor plan, and statically set to 80 MHz channels, then the > end-user WiFi experience is going to be really poor. If I then switch all > those APs to 20 Mhz only, of course it’s going to be a huge improvement. > Clearly, it was a poor design, and less about the channel width and more > about the person who thought they knew better. > > Of course, if the survey questions were more specific, and had questions > like, “Do you consistently receive the highest 4K stream rate from NetFlix”, > the satisfaction for this question may trend down. > > Jeff > > > > From: "[email protected]" > <[email protected]> on behalf of GT Hill <[email protected]> > Reply-To: "[email protected]" > <[email protected]> > Date: Tuesday, September 26, 2017 at 8:47 AM > To: "[email protected]" <[email protected]> > Subject: Re: [WIRELESS-LAN] Two RF Questions > > I know that this is just one example, but I was at a large university site > (Cisco Wi-Fi) that was running 20/40 channelization. After a switch to 20 MHz > only, there was a 35% improvement in end-user Wi-Fi experience. > > Jake – One feature that I think many people agree is missing in FRA is the > ability to dynamically turn off a radio. In some cases an extra radio in > either band hurts more than it helps. > > And to just stir the pot a bit, I wish there were SMALLER than 20 MHz > channelization. In many high density environments 20 MHz is just too big. > Give me some more radios at smaller channel sizes and I’ll show you a > spectacular Wi-Fi network. :-) > > GT > > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > <[email protected]> on behalf of Jake Snyder > <[email protected]> > Reply-To: The EDUCAUSE Wireless Issues Constituent Group Listserv > <[email protected]> > Date: Tuesday, September 26, 2017 at 9:39 AM > To: <[email protected]> > Subject: Re: [WIRELESS-LAN] Two RF Questions > > My challenge, as I’ve stated on this list before, is that Mac OS X > preferences width in its AP selection criteria. So while you may get more > capacity, in a large Mac environment you lose most of that with Macs hanging > onto APs linger and having to rate-shift down to slower PHY speeds due to > that AP having a wider channel than its neighbors. Yes, it’s dumb. But he’s > the driver of that lambo. > > Also, couple that with increasing the noise floor by 3db every time you > double the channel width and there are many cases where your lambo just spins > it’s tires. All that power and you can’t hook it up. > > Remember that spectrum is our constraining resource. > > Figure out what width of channel you can run in a building, and run that. > That’s the best use of spectrum and sure to give you the most smiles/hour on > your lambo. > > I really like what cisco did with FRA. Give me the ability to see what it > thinks the overlap is. I would LOVE to see the same with DBS, and give me > what width it thinks all the APs in the building can pull off. > > Sent from my iPhone > > On Sep 26, 2017, at 8:19 AM, Jeffrey D. Sessler <[email protected]> > wrote: > > It’s surprising to me that anyone would purchase a Lamborghini, then > disconnect ten of the twelve cylinders and drive it at 25 mph on the autobahn. > > When I see static 20 MHz channels, or using 40 MHz in only limited areas, I > wonder what’s behind the purposeful neutering of the system. If you are a > Cisco customer running 8.1 or above, and not using DBS (Dynamic Bandwidth > Selection), then it’s the equivalent of the Lamborghini above running on only > two cylinders. > > Don’t miss out on the significant advancements in bandwidth management. Free > those resources spent doing point-in-time simulation and surveys for > something the software doesn’t already do far better at. I promise, DBS won’t > hurt a bit and your users will thank you a hundred times over. > > Jeff > > > From: "[email protected]" > <[email protected]> on behalf of "Street, Chad A" > <[email protected]> > Reply-To: "[email protected]" > <[email protected]> > Date: Tuesday, September 26, 2017 at 6:59 AM > To: "[email protected]" <[email protected]> > Subject: Re: [WIRELESS-LAN] Two RF Questions > > What is your reasoning behind not wanting 40 megahertz channels if you have > plenty of overhead with your channel utilization? People saying you should > or should not do something without Gathering any type of metric worry me. > > On Sep 25, 2017 3:28 PM, Chuck Enfield <[email protected]> wrote: > 1. Enable it in places to check for radar events. If you get few, then > yes. Client devices are almost fully capable now. Hidden SSID’s are the > only issue. Some clients don’t probe on DFS channels, and will only respond > to beacons. Make sure 2.4 is usable for the small number of incompatible > devices. > > 2. No. Don’t even consider 40MHz unless you’re using almost all the DFS > channels, but even then you’ll probably have to disable it in some high > density areas. > > > > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > [mailto:[email protected]] On Behalf Of David Blahut > Sent: Monday, September 25, 2017 3:17 PM > To: [email protected] > Subject: [WIRELESS-LAN] Two RF Questions > > > > Greetings, > > I have two hopefully simple RF related questions: > > 1. Should I enable the extended UNII-2 channels campus wide? > > 2. Should I enable 40Mhz channel width campus wide? > > In other words what are you doing on your campus and what is the "best > practice? > > > > Our wireless infrastructure: > > > > 3 Cisco 5508s running 8.2.141.0 > > > > 20 - 3800 APs > > 368 - 3700 APs > > 414 - 3600 APs > > 8 - 3500 APs > > 7 - 1810 APs > > 32 - 1142 APs > > > > Prime 3.1.0 > > > > Thanks for your input. > > David > > ********** 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. > > > > This e-mail message (including any attachments) is for the sole use of > the intended recipient(s) and may contain confidential and privileged > information. If the reader of this message is not the intended > recipient, you are hereby notified that any dissemination, distribution > or copying of this message (including any attachments) is strictly > prohibited. > > If you have received this message in error, please contact > the sender by reply e-mail message and destroy all copies of the > original message (including attachments). > ********** 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. > ********** 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.
