Hi Yaakov, Just got a chance to read your draft. I agree with the comments of the others that this is a very interesting work. I'll just add a few points.
1. The use of clock time as deadline requires network synchronization, and accurate measurement of per-link propagation time, which can somehow limit the application scope of this work. Alternatively, one can simply budget a device latency which require a router/switch to obey. In case the overall budget is evenly divided by the hops, a single parameter is enough. Of course, if one wants to customize the budget on each hop (which might be necessary considering the different capability/capacity of each hop), a stack is still needed. 2. Mechanism should be provisioned to track where the timing requirement is violated and by how much (e.g., using timestamp or flag). This would be very useful for troubleshooting. 3. Recently programmable scheduler research has proposed several primitives such as PIPO and PIEO and provided feasible hardware implementations. The scheme proposed in this draft can easily fit into these primitives. Best regards, Haoyu From: spring <[email protected]> On Behalf Of Yaakov Stein Sent: Tuesday, February 23, 2021 5:14 AM To: [email protected]; [email protected]; [email protected] Subject: [spring] new draft on segment routing approach to TSN All, I would like to call your attention to a new ID https://www.ietf.org/archive/id/draft-stein-srtsn-00.txt<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Farchive%2Fid%2Fdraft-stein-srtsn-00.txt&data=04%7C01%7Chaoyu.song%40futurewei.com%7C603ba064d1ef4220fa0508d8d7fd0e0b%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637496829160448349%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=Fq7J2ogbHh%2B26TZ2dRc82eUhJkwAOSWdnvR1G68r5p8%3D&reserved=0> which describes using a stack-based approach (similar to segment routing) to time sensitive networking. It furthermore proposes combining segment routing with this approach to TSN resulting in a unified approach to forwarding and scheduling. The draft is information at this point, since it discusses the concepts and does not yet pin down the precise formats. Apologies for simultaneously sending to 3 lists, but I am not sure which WG is the most appropriate for discussions of this topic. * DetNet is most relevant since the whole point is to control end-to-end latency of a time-sensitive flow. * Spring is also directly relevant due to the use of a stack in the header and the combined approach just mentioned. * PCE is relevant to the case of a central server jointly computing an optimal path and local deadline stack. I'll let the chairs decide where discussions should be held. Y(J)S
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