Comcast Network Peer Survey on DSCP/ECN for L4S

Hi – Comcast is working on the implementation of ultra-low latency networking, leveraging the IETF’s upcoming L4S standard. This standard will require passing ECN and DSCP markings across network boundaries. As a result, we are interested in your perspective on this and in how you handle markings today. We have a short survey that should only take a few minutes to complete. Take the survey at

While any network operator is welcome to take this, we are particularly interested in any networks that are directly interconnected with us today.

Thank you!
Jason Livingood

Comcast – Technology Policy & Standards

PS – Apologies if any of you get a duplicate of this request via other channels.

I would argue that question 9 needs an option of "Both".

Secondly, two additional good questions to ask would be: are the ECN
values presently being treated as RFC3168?

Are the ECN values being modified by any AQM implementations (WRED,
FQ_CODEL, etc) on any switch or router in transit?

This seems to be missing some of the reasons/why things are remarked, perhaps it would be wise to bring some of the people interested in this to the various vendor-specific lists or such?

For example, for some hardware types, enabling any sort of rate shaping at all will rewrite the DSCP values, even for packets that do not traverse the shaped interfaces.

- Jared