I’m really only starting to play in this space over the last year but below is my thoughts.
Ideally you want same channels as far away from each other as possible, interference signal levels travels further than acceptable coverage (so you might target 25SNR for signal but I think something like 4 SNR can be decoded and therefore shares airtime). Using 2e helps to achieve distance between re-used channels. You can do manual or rely on auto, depending on who you talk to you’ll get different answers on preference. If it’s working and users are happy…. It’s a great start. We use auto, but I’m getting fed up of seeing the same channel used on adjacent AP’s even on single story buildings… (cisco 8.0 code). Having said that we don’t get many complaints from users about wireless problems so any issues that exist aren’t bad enough to incur any wrath….. Users do have a tendency to not report wireless problems though. And performance issues caused by CCI probably fit the bill of not being reported. We are playing with manual designs and are using Ekahau Site Survey to design these. If you don’t have access to them at this stage I know some that use the vendor auto to set the initial channel/power, then set to manual and make adjustments as see fit. Testing is the only way to really know if your not getting CCI. Aircheck G2 has been mentioned in the other post as a good handheld solution. Metageek tools like Chanalyser might be one of the cheapest options for a RF spectrum analyser but I believe something like airmagnets solution is considerably better (at a cost). But have a look at the tools mentioned in the other post. Anything is better than nothing. You basically want to identify how many of your AP’s can be seen on channel X from the location your testing. If there is channel overlap and it’s not the same channel as the AP that is covering that area, it may not be a big issue. Yes wattage options change per channel, it’s such a pain for manual config ☺ Cisco do this very frustratingly by providing power levels that change but the actual power is invisible in the GUI. I think that’s going to be “fixed” in a future release. -- Jason Cook Technology Services The University of Adelaide, AUSTRALIA 5005 Ph : +61 8 8313 4800 From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Lee H Badman Sent: Thursday, 1 December 2016 12:39 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 5GHz Channel Width Hi Donald, I’m not quite following the questions. Where we are very dense and likely to risk channel overlap with 40, we use 20. Examples- our stadium, dense residential environments, very RF porous buildings that are also dense. In 5 GHz, we *generally* let RRM pick channel, but often overrule it on power. Most max power differences allowed across the individual 5 GHz channels don’t come into play in our *generally* low-power cells. And we are not yet using DFS channels whole-hog, but do have pilot spaces in use. Our way certainly isn’t the only way, but has proven reliable for us over time. -Lee Lee Badman | CWNE #200 | Network Architect Information Technology Services 206 Machinery Hall 120 Smith Drive Syracuse, New York 13244 t 315.443.3003 f 315.443.4325 e lhbad...@syr.edu<mailto:lhbad...@syr.edu> w its.syr.edu SYRACUSE UNIVERSITY syr.edu From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Donald Ambrose Sent: Wednesday, November 30, 2016 7:24 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: Re: [WIRELESS-LAN] 5GHz Channel Width Any advice on manually setting up the 5 Ghz channels? Also I would like to use the DFS channels so that I can get a wider range to choose from. But I have noticed that the wattage correspond to the channel I choose in this band .So would it be advisable to use two 165s close enough or should I design the channel selection keeping the distance into consideration as well. Thanks Donald Ambrose From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Lee H Badman Sent: Tuesday, November 29, 2016 7:58 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: Re: [WIRELESS-LAN] 5GHz Channel Width 20 in our dense spaces, 40 where it can be done safely- about 50/50. Lee Badman (mobile) On Nov 29, 2016, at 6:09 PM, Jason Cook <jason.c...@adelaide.edu.au<mailto:jason.c...@adelaide.edu.au>> wrote: It all comes down to requirements & design, if you can have 0 channel overlap while using 40Mhz then go for it… This is likely to be quite a challenge in multi-floor environments. Using tools like Ekahau Site Survey and Airmagnet survey will help design and verify these installs. We went from 20 to 40 a few years back, but move back to 20 by default early last year. We have a few 40Mhz locations where we can, we could probably do a lot more but unless we have time to design and test we leave things at 20. Here’s come CWNE’s talking about it https://vimeo.com/158370545 Starts 27:50 Though the rest of the video is pretty interesting too -- Jason Cook Technology Services The University of Adelaide, AUSTRALIA 5005 Ph : +61 8 8313 4800 From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Trinklein, Jason R Sent: Wednesday, 30 November 2016 8:05 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU<mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> Subject: [WIRELESS-LAN] 5GHz Channel Width Hi All, I was just reading a blog article that heavily recommends not to use 40Mhz channel width in multi-floor environments, particularly where many 5GHz radios are used (particularly in our case with Xirrus multi-radio APs). Our campus presently uses 20MHz channel width in all buildings. We are testing and considering 40MHz width because of the bandwidth benefits for clients. What do you use on your campus? Have you found that setting a 40MHz channel width on your 5GHz radios has caused too much interference? Here is the article: http://divdyn.com/dual-5ghz-radio-aps/ Your thoughts are appreciated. -- Jason Trinklein Wireless Engineering Manager College of Charleston 81 St. Philip Street | Office 311D | Charleston, SC 29403 trinkle...@cofc.edu<mailto:trinkle...@cofc.edu> | (843) 300–8009 ********** 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/. This communication together with any attachments is for the exclusive and confidential use of the addressee(s). 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