Mac Best Practices?

[rvandolson]

Hoping I can tack on some technical specifics here, but curious if anyone has any best practices for Mac clients on Cisco WLC-based networks.  We have a mix of 35xx-37xx AP's with 5508 WLC's and it seems that the MacBook Airs (maybe some Pros too?) tend to have the most issues.  Random disassociations/reassociations, etc.  Perhaps some (much?) of this is on the client side, but the issues seem to go away if Apple's AirPort Extremes are in use as the AP (could also be placebo effect :)).

That said, figured some of you may have large-ish deployments with many Mac clients.  Any tips you could provide would be much appreciated.

[Rasika Nayanajith]

This may give some guidance, though it is not specific  to Mac, but for Apple mobile devices

http://www.cisco.com/c/en/us/td/docs/wireless/technology/vowlan/bestpractices/EntBP-AppMobDevs-on-Wlans.pdf

HTH

Rasika

*** Pls rate all useful responses ***

[rvandolson]

Thanks!  Have seen that.  Was hoping for some responses from folks supporting a lot of Macs in their environment.

[Matthew Peterman]

Basically same setup. Mostly 5508s with 3502i, 3602i and 3702i APs. A couple of WISM2s deployed, but mostly 5508. 90%+ Mac deployment. 20Mhz channel widths everywhere. Open SSID for guest WiFi and WPA2 Enterprise for internal. 2.4Ghz turned off on a lot of APs due to high density deployment. DFS disabled. Nothing too special. Not too many issues with disassociations. Not sure where your problems would be stemming from. Able to replicate the issue regularly or is it seemingly random?

You could use the built in OS X wireless diagnostics to determine a possible issues or start some debugging on your WLCs. https://support.apple.com/en-us/HT202663

[daniel.keith]

What code is your controller on? I've found 7.6.130.0 to be fairly stable with Mac's, also one setting that seemed to help was to change the TCP Adjust MSS to 1300. Go to Choose WIRELESS > Access Points > Global Configuration, Global TCP Adjust MSS, enable and enter 1300.

[Matthew Peterman]

Also running 7.6.130.0 here too. Been a very good release for us. Been testing 8.0 and it has played fairly nice as well, but not tested to scale. 

[rvandolson]

Maybe 2.4 is part of our issue -- it's enabled everywhere currently.  Looking at disabling it in a test area now as some clients seem to insist on associating at 2.4/11Mbps. :-)

Not able to reproduce the re-association issue on-demand, but it does occur frequently enough (randomly-ish?) that we could potentially leverage the toolset you suggested to dig deeper.

We also have issues (quality related) with these Mac users attempting to use Lync (VoIP) over Wifi where PC users typically do not.  Could be more around the fact that the Macs don't tag packets properly (we do have AVC on, but presumably a portion of the traffic would be untagged prior to it hitting our WLC's).

[Matthew Peterman]

Well I certainly would disable rates below 12mbps to preventing those far off clients from associating. We have ours set to 24mbps mandatory to encourage roaming as much as possible and prevent clients from hopping on so far out of buildings. 

If your wireless design has full 5GHz coverage, then you 2.4 radios hopefully aren't at 100% power. In our design most 5 Ghz radios are at power level 6 or below, so as you can imagine 2.4 Ghz has to be off on many and turned way down. 

[rvandolson]

Thanks.

Also -- curious (assuming you also allow and support VoIP on your wireless network) -- do you use WMM?  Recommendation we've been given is that it isn't really needed unless you're using actual wifi handsets rather than laptops with soft clients....

[Matthew Peterman]

No WMM. No WiFi handsets (well basically none. A few for testing purposes here and there, but no production deployments). Lots of softphone use on laptops, that performs just fine over WiFi and even over VPN from home which is way more latency and loss prone than the WiFi. 

[rvandolson]

Matthew -- wrt DFS, did you disable DFS the 'feature', or just disable the relevant DFS channels?

[Matthew Peterman]

Most have DFS completely disabled. Although I was on a controller today that had it enabled and many APs were using DFS channels so I guess we have areas we have DFS enabled. I'm all for having DFS enabled and letting the AP change channel if it needs to. RRM is smart enough to avoid the DFS channels if it frequently has to switch away from them. 

[rvandolson]

Thanks.  My understanding is this is something that must be done manually per AP?  Did you plow through it or find a way to script/automate (disabling DFS)?

Also, curious how you've distributed your WLC's.  We have two at our main HQ with remote locations in Flex mode.  Perhaps there'd be value in geographically dispersing a few additional... (we're only able to use AVC at the HQ location).

[Matthew Peterman]

Every remote location has 2 or more 5508s depending on how many APs. HQ has 40+ 5508s plus some WISM2s in there.  Using PI to manage. 

[jonathanw84]

Silly question, but how do you disable DFS altogether? I've opened a TAC case with Cisco regarding our 5ghz radios dropping and they recommended disabling the 4 DFS channels we are using - 52,56,60 and 64.