Re: [Ecn-in-quic] ECN in QUIC, quick review input wanted

[Magnus Westerlund <[e-mail]>]

Den 2017-12-18 kl. 15:53, skrev Eggert, Lars:
> On 2017-12-18, at 15:19, Magnus Westerlund <[e-mail]> wrote:
>> Frankly I don't quite understand why ACK and ECN must be in the same Frame. Yes, they need to be in the same IP packet, and have corresponding information coverage to make them useful. But, that I don't see require combined frames. What am I missing? Is it the case of retransmitting ACK frames, where one may have multiple ACK Frames from different times in the same frame alternatively, need to re-encode the corresponding ACK interval into one new frame?
> ACK frames are never RTXed, see https://quicwg.github.io/base-drafts/draft-ietf-quic-transport.html#rfc.section.9

Sloppy of me. Yes, so you create new ACK frames and corresponding ECN 
info going back to the point of confirmed to be received by sender ACK 
information. Thus, if each packet containing an ACK frame, you could 
include an stand alone ECN frame for the corresponding info.

I guess it becomes mostly a question of what is easiest to implement. An 
ACK and a combined ACK+ECN frame. Or one ACK and one ECN frame, where 
the later needs to be processed in the context of the first. Something 
for the people with implementation experience to answer.

Cheers

Magnus Westerlund

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