Hi, At Ericsson Research we are doing some prototyping of multipath QUIC (of the fully parallel kind). So far, we have very rudimentary support in our prototype but are about to take the next step.
Our initial implementation uses a single packet number space, which turned out to be a pretty clean addition to the path migration mechanism. Some care has to be taken with the ACK handling on both sides, but so far it has been straightforward. The key is that the sender has to keep track of over which path each packet was sent, but that is trivial to do. Some smartness with the ACK ranges is also needed, but you already need to prune them for the single path case. This is what I think I know about existing "active" multipath implementations, please correct me if I'm wrong: - picoquiq has experimental but undocumented support (open source) - Alibaba are running A/B tests with real users and have published a paper about it. The implementation is planned to be open sourced (this seems to be delayed). - Quentin De Coninck et al at UCLovain have a prototype and paper on multiflow QUIC, using unidirectional "uniflows" (open source) Are there any other existing or planned multipath prototype activities in the QUIC community? I would be particularly interested in: - Open source implementations (preferably in Rust :-)) - Public servers for interop testing - Designs with a single packet number space and the experiences collected. Separate number spaces, as in draft-liu-multipath-quic, will of course work; however, it would be interesting to also understand the cleaner single PN space alternative. Best regards, Michael Eriksson
