[Ecn-sane] The curious case of "cursed-ECN" steam downloads

[Jonathan Morton]

> On 3 Sep, 2023, at 9:54 pm, Sebastian Moeller via Ecn-sane <ecn-sane at lists.bufferbloat.net> wrote:
> 
> B) Excessive ECT(1) marking (this happened with a multi-GB download)

This *could* be a badly configured middlebox attempting to apply a DSCP, but clobbering the entire TOS byte instead of the (left justified) DSCP field.  Apparently Comcast just found a whole raft of these in their own network as part of rolling out L4S support.  Funny how they didn't notice them previously.

 - Jonathan Morton