Tariq, all, In response to: >Sam: regarding point 2, I aim to disable few 2.4G radios. As per your experience, should I be following some pattern ? Or disable every 4th one, for instance ? Highly appreciate your help, I can see you love HD wireless :)
I do indeed love HD wireless and I would not advocate a 'patterned' or 'predictive' approach to disabling (or enabling!) radios. While it's tempting to take a coarse approach to HD wireless design by disabling every x radio for example, you're only doing yourself a disservice. Your best approach is to perform empirical measurements in your environment and use those to determine your next actions. For example, if you took a measurement 'in the middle' of an auditorium and saw three radios in 2.4GHz (on 1, 6, and 11) and they were a) all within the expected signal strength you require for your application and b) did not have neighbors on the same channel below a reasonable noise level (say -80dBm or so, I would adjust nothing. If, on the other hand, you took a reading and saw 21 radios in 2.4GHz (7 each on 1, 6, and 11) and they were all hotter than -65dBm, I would say you've got a ton of work ahead of you. If you were looking for a 'light effort' way to accomplish this, one possible way is to start with all 2.4GHz radios turned off in your environment - measure your environment to ensure it's a clean starting point (no noise, no rogues, no anything). Then turn on three perimeter APs and statically assign them low power levels. If you can see them from all areas at 'very strong', stop - there is nothing more you can do at this point. If you have good separation between your APs, pick another three and do the same thing - continue till you find the balance recommended in paragraph one. Don't forget some of the most important rules of wifi: 1) your RF design (site survey) should trump any and all advice by way of empirical measurement and solid, tangible proof. 2) your RF environment will change quite dramatically between occupied and un-occupied. No one is surprised when their full auditorium doesn't work as well as when it's empty, but don't be surprised if an empty auditorium doesn't work as well as a full one either. 3) more than 1 AP on the same channel does *not* add capacity. In fact, it robs capacity by introducing more management traffic (overhead). There are novels written on HD wireless design and this topic treads heavily on one of the most complicated areas of being a WiFi network administrator. Much of our life is spent dealing with the abysmal number of limited channels available to us wether those be the 1, 6, 11 problem in 2.4GHz or silly admins trying to run 160MHz wide channels in 5GHz - same problem - our spectrum is precious (he says in his best Gollum voice). There's a reason that telco's pay millions of dollars for a narrow slice of spectrum to operate in - we don't have to pay for ours and we're quite wasteful relatively speaking. Don't waste 5GHz by using wide channels, don't waste it by not using all channels you can possibly use (especially in HD wireless designs). While I'm reluctant to claim that 2.4GHz is outright dead, I know of several institutions that are rapidly moving down the road of wholesale disabling 2.4GHz in favor of a 5GHz only deployment model. I don't think we're quite there yet, but I foresee a time in the near future where this could be a reality. Also stated: >FYI: Cisco is going to introduce Next Gen AP’s which will automatically adjust bandwidth (20, 40MHz etc.), automatically disable 2.4G radio or convert it to 5G radio or put it in monitoring mode. You're referring to a couple of different things here - the first of which is Cisco DBS (Dynamic Bandwidth Selection) which allows for differing channel widths to be automatically selected and is available today on all APs that support greater than 20MHz channels (basically anything 802.11n and newer) with a code update on your WLC: http://blogs.cisco.com/wireless/enhancing-hdx-introducing-dynamic-bandwidth-selection-automatically-choosing-the-best-channel-width In an HD wireless design, I'd advocate ignoring this and just using 20MHz channels. In a good design, this is what should happen anyway. :) The second feature (of decoupling radio states in a given AP) which will allow for automatically disabling the 2.4GHz radio will be coming in the next WLC software release, also supported on all existing AP platforms. The ability to convert your 2.4GHz radio to 5GHz (for dual 5GHz in a single AP) will only be supported on the AP2800 & AP3800 platforms: http://www.cisco.com/c/en/us/products/wireless/aironet-2800-series-access-points/index.html http://www.cisco.com/c/en/us/products/wireless/aironet-3800-series-access-points/index.html <marketing mode> The cool thing is that as the WLC software continues to improve and bring new features, we get many of those benefits without a hardware refresh. </marketing mode> Anyway, sorry for the novel all - it's a topic that I'm certainly passionate about and I hope that there is a nugget or two of good data in here if you've read all the way to the bottom. :) -Sam On Mon, Feb 15, 2016 at 10:23 PM, Tariq Adnan <t.ad...@unsw.edu.au> wrote: > Thank you everyone for your valuable tips. I’ve been trialling some > changes/features over the past few weeks. Once all done, I will share my > findings. May be it could help someone with HD design. > > *Sam*: regarding point 2, I aim to disable few 2.4G radios. As per your > experience, should I be following some pattern ? Or disable every 4th one, > for instance ? Highly appreciate your help, I can see you love HD wireless > :) > > FYI: Cisco is going to introduce Next Gen AP’s which will automatically > adjust bandwidth (20, 40MHz etc.), automatically disable 2.4G radio or > convert it to 5G radio or put it in monitoring mode. > > > Cheers, > > -- > > > Tariq Adnan > > > From: <Osborne>, "Bruce W (Network Services)" <bosbo...@liberty.edu> > Reply-To: The EDUCAUSE Wireless Issues Constituent Group Listserv < > WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> > Date: Friday, 15 January 2016 6:26 am > To: "WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU" < > WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> > Subject: Re: [WIRELESS-LAN] high density wireless improvement features > > Aruba also does a **very** good job on their LPV (Large Public Venue) > deployments too. I believe they are also usually lower cost than Cisco. > > > > > > > > *Bruce Osborne* > > *Wireless Engineer* > > *IT Infrastructure & Media Solutions* > > > > *(434) 592-4229 <%28434%29%20592-4229>* > > > > *LIBERTY UNIVERSITY* > > *Training Champions for Christ since 1971* > > > > *From:* Frans Panken [mailto:frans.pan...@surfnet.nl > <frans.pan...@surfnet.nl>] > *Sent:* Wednesday, January 13, 2016 12:27 PM > *Subject:* Re: high density wireless improvement features > > > > In addition to what Sam shared (thanks!), I think Aruba did a very good > job with their very detailed description of very high density design that > is well applicable for other vendors: > http://community.arubanetworks.com/t5/Validated-Reference-Design/Very-High-Density-802-11ac-Networks-Validated-Reference-Design/ta-p/230891 > -Frans > > Op 13/01/16 om 17:14 schreef Samuel Clements: > > Hi all! I'm new to the list (well, I've been lurking for a while), but > this seems to be a good time to say hi! High Density being near and dear to > my heart - I'd give the following guidance: > > > > 1) Don't underestimate your gear if you have good equipment. It's not a > stretch for a Cisco 2700/3700 to support 100+ active association (shameless > self-plug: http://nsashow.com/AP2700/). > > 2) There is such a thing as too much RF. If you're not disabling all but 3 > 2.4GHz radios in a single room, you're not disabling enough of them. If you > see two APs on the same channel (as a general rule) and they're both above > -80dBm, you're not adding any capacity to your RF. In fact, you're hurting > yourself. > > 3) Use narrow channels in 5GHz (20MHz), always. There is an overwhelming > need for density of users (aggregate throughput), not individual > throughput. This is one of the best ways to leverage the finite amount of > air we have to use. > > 4) Use all channels in 5GHz including 2e/DFS channels. The more channels > the better. If you're using a sane RRM product (Cisco does this for sure), > RRM will try to avoid stacking 2e channels next to each other. In the event > you have a client that doesn't support a channel you're using, this > improves the likely hood that they can still function on a further AP. > > 5) Once you hit a number of APs that matches the number of 5GHz channels > you have deployed, be very cautious about channel overlap (this is the same > as rule 2, just in 5GHz and further away). > > 6) Design for RRM and enable RRM (sorry Lee!). If you know how RRM works > (there are many and numerous white papers and Cisco Live sessions on the > specifics of how AP layout impacts RRM), you can safely run it without > shooting yourself in the foot. I can't speak to ARM since there doesn't > seem to be a good guide on how it actually works. 99% of the time, RRM > works every time. The great thing about Cisco RRM is that you can watch the > CLI of the process and it will tell you exactly what it's doing and why > it's doing it. Use min and max thresholds if you can't get it to do what > you'd like. > > 7) Use RF Groups to segregate your high density areas from other areas of > your campus. This allows you to tweak and tune your HD area without > impacting other users. > > 8) Use RX-SOP only when you've violated rules 2 and 5 and use it > sparingly. RX-SOP is like a brick wall. Once you hit it, your clients fall > off into never never land. > > > > I hope that helps! There is a ton of guidance that can be given for > designing cells (using directional antennas, stadium antennas with narrow > beams from far away, APs under seats, in walls, etc) but those are covered > in great detail elsewhere and all of the above advice can be taken > regardless of antenna or location of installation. > > -Sam > > > > > > On Tue, Jan 12, 2016 at 11:00 PM, Tariq Adnan <t.ad...@unsw.edu.au> wrote: > > Hello everyone, > > > > I am working on improving wireless performance in high density areas > (lecture theaters, auditoriums etc) and doing research on some features. I > would like to know if you people have made below changes and how was your > experience with it ? We're using cisco gear (3702i/e APs, WiSM2 > controllers, Prime 3.0). > > > > 1-set channel and power manually (not use RRM) : reduce power to limit > coverage and disable 2.4GHz radios on every 3rd/4th AP. > > 2-load-balancing > > 3-band-select > > 4-RX-SOP (already deployed and happy with it, channel utilization is > dropped) > > 5-optimized roaming > > 6-please suggest if i am missing something > > > > In our setup, same controller is handling APs from HD and non-HD (high > density) environments. My concern is if i make change which is controller > wide, for instance optimized roaming, it could improve performance in HD > areas but what could it do to non-HD areas (APs far away from each other). > > > > I am using airmagnet PRO and Prime planning tool for survey and planning > purposes. > > > > Thanks everyone for your precious time [image: 😊] > > > > Cheers, > > -- > > > > Tariq Adnan > > Network Engineer > > NSW, Australia > > ********** 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/. > ********** 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/.
