> Le 29 janv. 2026 à 11:02, Dave Cridland <[email protected]> a écrit :
> 
> Hey all,
> 
> Some of you have heard me talk about this at the Summit, but I'd like to 
> revisit/reexamine our QUIC binding to improve performance of XMPP on low 
> bandwidth. I'm not sure we'll get to this at the Summit, and there's not many 
> who want to talk about it so I wondered if this summit topic could have been 
> an email. (Except then we discussed it anyway)
> 
> The primary concerns on low bandwidth - beyond sending fewer bytes on the 
> wire - are round-trips and head-of-line blocking.
> 
> I think XMPP has a good story on round-trips; we're down to very few during 
> authentication and connection setup, and during normal messaging operation we 
> don't worry about latency at all.
> 
> Head-of-Line blocking, or HoL Blocking, is when - in our case - packet loss 
> causes the stream to stall until the packet is retransmitted, which is at 
> least a round-trip away - and can be more due to bandwidth-delay product.
> 
> At the same time, we cannot eliminate this entirely (by, say, sending stanzas 
> over UDP directly) because if we do that we lose the ordering. Out of order 
> messages can be confusing, and lead to bad misunderstandings.
> 
> The rules on this are in RFC 6120, and are rather more complicated than we 
> normally worry about - normally, we just process everything on a strea, in 
> order, and this does satisfy the rules. But the rules allow us to process 
> stanzas in any order we like, as long as 
> 
> So, what I'm thinking is a way to use the additional channels in QUIC such 
> that we open multiple channels on both C2S and S2S sessions, which would form 
> part of the same virtual stream, and we can distribute messages such that we 
> maintain ordering within messages where we need to, but allows us to 
> out-of-order (and avoid HOL Blocking) messages sent between unrelated jids.
> 
> This differs to the existing XEP, where each channel maps to a single XML 
> Stream and XMPP session.
> 
> Notes from the Summit:
> WEBTRANS would also be of interest, but "raw" QUIC has some advantages as 
> well, so we probably want both with a uniform approach.
> 
> So, my plan is to get an implementation together and a XEP.
> 
> Anyone else interested?

Yes. As Peter St-Andre and I started a thread some time ago, our use case is 
(deep) space messaging/chat where latency is significant, but QUIC can be 
configured to work very well in this environment. If we have a good spec, I'll 
have my team implement it using the Quinn QUIC stack and simulate it on our 
(deep space) testbed.

Regards, Marc.

> 
> Dave.
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