Re: [tsvwg] L4S status: #17 Interaction w/ FQ AQMs

["Tilmans, Olivier (Nokia - BE/Antwerp)" <[e-mail]>]

> > This is similar to DCTCP forcing the use/negociation of ECN, regardless of
> the actual
> > sysctl value, as it cannot provide its service without it (in other words,
> becomes
> > plains reno).
> 
> 	[SM] Sorry, that does not compute to me, if at all it points at a bug
> in dctcp that would merit fixing. In essence dctcp aims a specific niche
> where this can be toerated, but since yi aim for replacing all current CCs,
> you need to play by the rules. TCP Prague with ECN disabled should behave
> like Reno, it should IMHO accept that a systems admin sets policy and needs
> to respect the tools used for that purpose.

Forcing to initiate the negotiation of (Acc)ECN (i.e., sending a SYN with
ECE/CWR(/NS) set) does not imply that said negotiation succeeds (e.g., if
the remote endpoint does not implement/allow it).
If the handshake fails, then the CC has an explicit trigger that it should
fallback to something else (at the moment, both become plain new reno).


Best,
Olivier