Queries on DSCP packet marking

[Siddharth Toshniwal]

Hi all,

Is DSCP packet marking enabled by default for UDP media packets on WebRTC calls? Is yes, is there a way to disable this for a test? Is this the recommended way of doing that: https://developer.mozilla.org/en-US/docs/Web/API/RTCRtpSender/setParameters by tweaking the priority field?

On a related note: Is the googDscp constraint deprecated and inconsequential? Asking since our code still has that and wondering if we should remove it as dead code.

I came across https://issues.chromium.org/issues/40221833 which suggests DSCP marking should happen by default for WebRTC calls starting M102. However, on my dev/test setup (Chrome 130.0.6723.117 on MacOS) I do not see packets being marked with Assured Forwarding (AF41) and instead see zero (Default forwarding) for all TURN packets in the PCAP (regardless of the value for googDscp). Wondering if this is a setup issue on my end or something specific to Chrome on MacOS.

Any insights are greatly appreciated.

Regards,

Siddharth