MS Team and WLC best practise (QoS, AVC etc)

[atsukane]

Due to COVID-19 lockdown, we've implemented MS Teams a few months back.

Now that small number of users are back in the office and using mobile devices for Teams, we started receiving reports of some issues on corporate mobile WLAN (MDM managed iPhones) and guest WLAN.

Mostly to do with the call quality, e.g. call drop for half a second every 3ses or so.

WLC is located at the primary data centre, and users' internet access is locally switched with FlexConnect.

Since those reports, I’ve made some update based on docs I’ve found.

As there aren't any MS Teams specific doc by Cisco that I could find, I used Lync as reference and updated the config as follows:

On ASA, allowed UDP 3478-3481 to 13.107.64.0/18, 52.112.0.0/14, and 52.120.0.0/14.

 From <https://docs.microsoft.com/en-us/microsoftteams/prepare-network>

On WLC,

SSID QoS = Platinum

WMM Policy = Allowed

Audio = Platinum

Video = Gold

Application-Sharing = Silver

File-transfer = Bronze

Lync Server = Enabled

11k Neighbour list = Enabled

AVC profile

ms-lync-audio mark 46

ms-lync-video mark 34

FlexConnect AVC profile

ms-lync-audio mark 46

ms-lync-video mark 34

Lync Server = Enabled

Port = 15790 (default)

Protocol = Http

 From  https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-1/Lync_SDN/b_Lync-Client-Server-in-Cisco-Wireless-LAN.html

I understand from the previous discussions for WLC/Lync/NBAR2/AVC related discussions that:

• A lot of client devices/applications does not correctly mark traffic as per WMM (Wi-Fi Multimedia Traffic Management) classification.
• It is purely up to end device to correctly classify traffic within the wireless media. AP does not have control how end devices tagging user priority (UP) in 802.11 frame. AP simply use this UP value in 802.11 frame to map QoS values in CAPWAP headers and subsequently this will determine how packet will get QoS treatment within wired media.
• Most of the apple devices does not correctly classify traffic with required UP value. In this case no prioritization within the wireless cell & further in wired media as well.

I saw on the above Cisco doc that 'This WLAN can also be used for Skype and the user would want those packets marked with a DSCP value of 20.' but haven't added this at this time. Not sure whether this is required?

Also, it is not clear to me what ms-lync and ms-lync-control in AVC Applications, and ms-lync and ms-lync-media in FlexConnect applications list. Didn't find NBAR2 doc that helpful understanding what is.

Lastly, when I had a voice Teams voice call with a colleague in the office, I couldn’t see anything on AVC statistics that is Lync related.

I have to monitor how it goes following the above change but I’m not convinced that this hasn’t made much improvement.

Please advise how/where to progress from here!

WLC 5508 running 8.3.143.0

AVC Engine 23

AVC protocol pack 24

WAPs AIR-AP3802I-E-K9

Switch where APs are connected are CAT3850s running #3.06.09E

My understanding is that 3850 switches trust markings on the wired ports so I didn’t make changes to switchports

ASA 5555-X running 9.4(4)29

Many thanks,

[patoberli]

I have enabled the following on 8.5 for AVC and got fairly good results (meaning, I didn't get any complaints so far):

skype
voice-and-video
mark
34
Bidirectional
NA

ms-lync-audio
business-and-productivity-tools
mark
46
Bidirectional
NA

ms-lync
business-and-productivity-tools
mark
34
Bidirectional
NA

ms-lync-video
business-and-productivity-tools
mark
34
Bidirectional
NA

statistical-conf-audio
other
mark
46
Bidirectional
NA

ms-services
other
mark
34
Bidirectional
NA


ms-office-365
other
mark
34
Bidirectional
NA


internet-audio-streaming
other
mark
46
Bidirectional
NA

Please note, I haven't really made a lot of testing, but those were some of the "detected" applications while some users were on-site and used teams (and other communication services). 

[atsukane]

Thank you.
I'll try those options as well.

[patoberli]

One more thing, the marking is always the default value (Gold, Silver and so on, I only selected the application and the option Mark, the rest I left default).

[UWStoutTelecom]

I have been having the same issue with teams (broken up voice coming to client for the most part) including running a continuous ping to our server room when it happens and the pings time out randomly at the same time as a voice problem.

I have updated setting to match settings from this string but has not resolved the problem.

We are running,

5520 in HS SSO

Ver.8.10.122.0

Protocol Pack 40

Engine 34

AP's  
AIR-AP1815W-B-K9
AIR-AP2802E-B-K9
AIR-AP2802I-B-K9
AIR-CAP2702E-A-K9
AIR-CAP2702I-A-K9
C9120AXI-B

thanks,

[patoberli]

This can be a lot of things. How is the AP and radio interface load when you have interruptions?

Are the client wireless drivers up to date? 

If you check the WLC logs (or a debug), is the client roaming when the interruptions happen?

[atsukane]

We've seen a lot of interference with 11b. So only allowed 11a on one of the WLANs and the signal quality seems to have improved.

Slightly worried about doing this on the guest WLAN as some important guest might show up on an old device that only supports 11b.

Suppose we can enable 'band select' but I see this is not recommended for VoIP. 

thanks,

[patoberli]

11b rates?!? You really still have devices with only 11b and no 11g or 11n? I have disabled all 11b rates since years and never had complaints from external guests.

[atsukane]

Thanks, that's good to know.

We only allowed 11a radio on per WLAN basis.

Do you mean you've disabled 11b globally? 

[patoberli]

Yes, I've disabled all 11b data rates globally, that means I've set the following data rates on disabled:

1, 2, 5.5, 11 Mbps



And on 5 GHz I disabled the following:

6, 9 and 12 Mbps





This for various reasons, but the main one is performance.

[atsukane]

@patoberli 

Thanks, that's very helpful.

Currently we have 1-9Mbps disabled, 11Mbps Mandatory and then everything beyond that are supported.

On 5Ghz, 6 and 9 are disabled, 12Mbps supported and beyond that are supported.

[patoberli]

I suggest to also disable 11 Mbps to completely disable 11b and thus DSSS. This actually should make the channel by 2 Mhz smaller (from 22 to 20 Mhz), although I'm not 100% sure if this actually takes place or make a difference.

[PatilChandan]

What about 9800 series Configuration i am facing ping drop to MS team

[patoberli]

Better open a completely fresh thread with the problem you have. Also mention the AP type, WLC model and used software release.

[JPavonM]

Have you checked channel utilization while having the connectivity issues? Channel congestion due to excesive devices connected to the same AP/radio, or same channel in the area, could be a problem for these near real-time applications. I would suggest to check that value for APs on the area to see how it looks like during the issues. This command is for C9800:
show ap name <APname> auto-rf dot11 5ghz slot 1 | sec Channel Assignment Information|Load Information|Client

Last but not least, as most of the connectivity issues comes from the client side, as @patoberli  recommended before, update drivers and get all operating system's patches. Additionally it would be great if you can deploy QoS profiles in the devices (Windows, MacOs and Linux) to improve transmission as there is not QoS mark in the Apps by default. And enforce some best practices from ALL users while someone is on a call or meeting, as doing things like sharing files between them, downloading content, upgrading software/OS, opening remote content, or any other traffic with huge load, could impact these sensitive applications. I know this is complicated, but if there is little room to control that, check how it is like on a calm area such as meeting rooms with dedicated APs in that area.