Question about Teams QoS guidance - port range sizes

[David Phillips]

In the Teams QoS documentation there are a couple pieces of information that I have questions about:

"Selecting a port range that is too narrow will lead to dropped calls and poor call quality. The recommendations below should be a bare minimum." - I was planning on using the default 50000:50019, 50020:50039, 50040:50059 ranges.  Is there guidance for taking a more educated guess at these port ranges?

[#2 · Accepted solution]

@David Phillips 

Enabling QoS on the meeting policy is a good start. That switch will force certain clients - mobility & Mac OS clients - to mark packets as they leave their respective devices. That switch does not guarantee QoS for packets that leave the Microsoft service and traverse the internet. Microsoft will provide QoS by default for their networks up until the point it leaves. After that, no QoS is present, and the customer must re-enable QoS markings upon ingress to their network (typically at the firewall).

Windows client endpoints still require Group Policy Based settings to get DSCP tags applied. The meeting policy configuration has zero bearing on Windows endpoints.

Stick with the default port ranges unless you have a reason to go larger, not smaller. ICE/STUN/TURN will negotiate several ports per call, so the default settings will allow at least some level of having multiple calls active/on-hold. If you know people will need to handle 10+ simultaneous calls, you can bump the range up to what it used to be in the OCS days, which was 40 ports per modality.

[#3]

@rovert506 your explanation and answer makes complete sense.  I'm still stuck in SfB Server admin mode, I need to start breaking out of that!  Thanks for the answer, super helpful.