Re: [tcpm] WGLC comments for draft-ietf-tcpm-dctcp-04

[Michael Welzl <[e-mail]>]

Hi,

I haven't read the draft since long ago (one of the first versions), but I just read this dialogue and I have only one comment, so I'm removing everything else:


> ---
> 
> 3.4.  Handling of SYN, SYN-ACK, RST Packets
> 
>   " The switching fabric can drop TCP packets that do not have the ECT
>    set in the IP header.  If SYN and SYN-ACK packets for DCTCP
>    connections do not have ECT set, they will be dropped with high
>    probability.  For DCTCP connections, the sender SHOULD set ECT for
>    SYN, SYN-ACK and RST packets."
> 
> - I'd take the position that the fabric can and will drop any packets under overload, as per RFC7567. I'd prefer to explicitly state that to avoid a misconception that ECT eliminates all drop (rather than nearly all drops).
> 
> 
>>> Change this to : " If SYN and SYN-ACK packets for DCTCP connections do not have ECT set in the IP header, they will likely be dropped by the switching fabric under load. For DCTCP connections, the sender SHOULD set ECT for SYN, SYN-ACK and RST packets."

To me, "will likely be dropped by the switching fabric under load" doesn't sound quite right - as if they would most probably be dropped whenever there is any form of load (no matter how much). I would suggest to change this to "...they are more likely to be dropped by the switching fabric under load."

Cheers,
Michael