Hello Lucas When a PDU session is established (PDU session is like setting up L2) a set of attributes will be exchanged between the UE and the 5G network. Part of the is the type of PDU session, such as multiaccess-PDU with steering mode information (e.g. load balancing, active-standby, etc. see the presentation for more details). The MP-QUIC connection is established per IP flow (5 tuple). With this information the UE will steer the traffic to the corresponding multipath-quic connection.
Best regards Hannu From: Lucas Pardue <[email protected]> Sent: Sunday, October 25, 2020 8:19 PM To: Flinck, Hannu (Nokia - FI/Espoo) <[email protected]> Cc: Florin Baboescu <[email protected]>; David Schinazi <[email protected]>; Mirja Kuehlewind <[email protected]>; [email protected] Subject: Re: More context on ATSSS use case Hey Hannu, On Sun, 25 Oct 2020, 18:05 Flinck, Hannu (Nokia - FI/Espoo), <[email protected]<mailto:[email protected]>> wrote: Hello David and others, ATSSS supports low latency applications in the following way (this is a quote from 23.700-93) as part of its “Priority-based” mode: “RTT Threshold: Supported by using the RTT estimation mechanism defined in draft-ietf-quic-recovery, with which the QUIC protocol can estimate the RTT of a QUIC connection. Example of ATSSS rule using this steering mode: "Send the traffic of App1 to the access with RTT < 100ms; if both accesses have RTT < 100ms, send it to non-3GPP access". … As long as the selected access has RTT < 100ms, the traffic can remain on this access.” I hope this clarifies that ATSSS is supporting what was called as Interactive service/Siri service in Christoph’s presentation. And as explained by Mirja earlier it is the application that requests what kind of session it would like to have. So part of the benefit of QUIC is that connections can be reused for different purposes. Using streams I can handle both an application that requires low-latency (such as an API) along with bulk data transfer (such as a software download) that has no hard requirement for completion time. Iiuc ATSSS correctly, all it can do is forward QUIC packets. So how can it pick the correct path the cases where a connection is mixed use? Cheers Lucas
