SPRING @IETF-117

Wednesday 26 July 2023
Room: Continental 5
09:30-11:30, Local

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SPRING WG Meeting Agenda

09:30 SPRING Status - Chairs (10 mins)

09:40 Compressed SRv6 Segment List Encoding in SRH (10 mins)

Presenter: Weiqiang Cheng
draft-ietf-spring-srv6-srh-compression

Joel Halpern: The issues will need to be confirmed in the mailing list, particularly the issue 1. We need the feedback from the WG.

Weiqiang Cheng: The github is updated with the issues. We would like the WG to review.

Joel Halpern: Please provide a thorough review of the documents from the wg perspective.

QUEUE CLOSED due to running out of time.

Martin Vigoureux (Chat Panel): A number of IANA values are still not allocated.

Joel Halpern (Chat Panel): For implementation a number of code points have been allocated using the FCFS policy, we need to make sure things line up at the end of the process.

09:50 Bidirectional Forwarding Detection (BFD) in Segment Routing Networks Using MPLS Dataplane (10 mins)

Presenter: Greg Mirsky
draft-ietf-spring-bfd

Ketan Talaulikar: Thank you for taking the feedback and including S-BFD. SR Policy has Segment Lists (SLs) under a Candidate path for load-balancing. Monitoring should be on per SL basis.

Greg Mirsky: It is not strict in the ECMP environment. BFD uses the same encapsulation as data packet that is expected to traverse a particular candidate path.

Ketan Talaulikar: Not about loose or strict path. Refer to RFC9256 to see the hierarchy. Should monitor each of the SLs under a candidate path.

Greg Mirsky: Take it offline.

Ketan Talaulikar: Why only mentioned the return path in S-BFD section?

Greg Mirsky: S-BFD does not create state.

Ketan Talaulikar: Return path can be specified even for S-BFD. Let us take it to the list.

Jeffrey Haas: In the IDR recent session, there is this draft draft-chen-idr-bgp-sr-policy-cp-validity. Candidate path is protected by BFD. That will help clarify your text.

Greg Mirsky: Will consider it. Welcome more feedback in the mailing list.

10:00 Enhanced Performance Measurement Using Simple TWAMP in Segment Routing Networks (15 mins)

Presenter: Rakesh Gandhi
draft-gandhi-spring-enhanced-srpm

Alvaro Retana: The authors request to merge the draft with an IETF WG draft. Show hands if any objections? -- NO hands.

Joel Halpern: We will confirm in the mailing list.

10:15 S-BFD Path Consistency over SRv6 (10 mins)

Presenter: Changwang Lin
draft-lin-sbfd-path-consistency-over-srv6

Greg Mirsky: Current version of the WG draft about the U-BFD, U-BFD is only applicable to single hop. Not sure it is applicable to your scenario which has more than single link. How this mapping between Segment List1 and Segment List2 occurs on a system (reflector or echo-reflector) that receives a BFD packet? All the processing is in the forwarding plane, so in fact the BFD is not involved.

Joel: More details, complicated, so we need to take it to the mailing list.

10:25 Problem statement for Inter-domain Intent-aware Routing using Color (10 mins)

Presenter: Dhananjaya Rao
draft-hr-spring-intentaware-routing-using-color

Alvaro: Many authors in the draft right now. Please reduce.

Dhananjaya: Yes, we will.

10:35 SR Policy Group (10 mins)

Presenter: Wenying Jiang
draft-cheng-spring-sr-policy-group

Ketan Talaulikar: Parent SR policy is the composite candidate path as defined in RFC9256. Whether we want to document a use case? It is a configuration template. It does not need to be standardized.

Weiqiang Cheng: Parent SR policy has been defined. The SR policy group is new. It doesnot need any new extensions but it will simply the configuration. The draft can be informational. The solution is useful based on our experience. Hope the WG can adopt it.

Ketan Talaulikar: I will leave it to the wg to decide.

Jim Guichard: The draft currently is not informational. Please make sure.

Joel Halpern: Seems to be duplicated stuff. We need to take it to the mailing list.

Alvaro Retana: We are running out of time. We will take it to the mailing list.

Weiqiang Cheng: The authors would like to ask for WG adoption as an informational draft.

Ketan Talaulikar (Chat Panel): The Question is if the WG wants to consider adopting such work items - to me this is just one form of "configuration template". Vendors/operators are free to form their own templates on the routers or in their automation systems.

10:45 Flexible Candidate Path Selection of SR Policy (10 mins)

Presenter: Yisong Liu
draft-liu-spring-sr-policy-flexible-path-selection

Ketan Talaulikar: Another draft on cp validity - draft-chen-spring-sr-policy-cp-validity. It may be complementary. The author should consider to merge.

Greg Mirsky: Please consider the work in IPPM: https://datatracker.ietf.org/doc/draft-ietf-ippm-pam/.

Andrew Stone: Is the utilization on the path or on the headend?

Yisong Liu: On the headend for every single segment list.

Cheng Li: It is quite useful. I am interested.

Gyan Mishra: It will make the policy more dynamic. You are adding the intelligence on picking the best path.

10:55 SRv6 Context Indicator SIDs for SR-Aware Services (10 mins)

Presenter: Mengxiao Chen
draft-lin-spring-srv6-aware-context-indicator

Daniel Bernier: Is the draft Informational or Standards?

Mengxiao Chen: Standards.

Daniel Bernier: What happens if the service aware function doesnot understand the information being received? Maybe you can follow in the list.

Daniel Bernier: It is going to be a challenge since every function needs to be service aware and comply to this.

Mengxiao Chen: I will response in the mailing list.

11:05 SR-MPLS FRR Extension (10 mins)

Presenter: Huaimo Chen
draft-chen-spring-srmpls-frr-ex

Joel Halpern: Not as a Chair, not sure there is a clear procedure to differentiate the two cases: whether it is wrong or failed SID.

Huaimo Chen: We can find a way to differentiate it or avoid it.

Yao Liu: Similar question. Hard to implement.

Huaimo Chen: A separate draft on distributing information for BSID to upstream node.

Yao Liu: Not only BSID, but also other SIDs.

Huaimo Chen: We have a simple solution for adjacency SID.

Joel Halpern: We need to see a description in the mailing list or the draft.

Andrew Stone: There is a sentence in the draft "Distributing a BSID is out of scope". You could make it more visible to the WG.

Joel Halpern: It may be out of scope of the draft. But you cannot solve the problem without it.

Jeff Tantsura: I disagree with the problem statement. You complicate the control plane and data plane. The problem you are trying to solve is a corner case.

11:15 A Framework for Constructing Service Function Chaining Systems Based on Segment Routing (10 mins)

Presenter: Hongyi Huang
draft-li-spring-sr-sfc-control-plane-framework

Cheng Li: It is useful. If you have any interest please contact.

Joel: The session is now finished. Please go to the mailing list to continue the discussions.

Speaker Shuffling Time/Buffer: 5 minutes
Total Presentation Time: 120 minutes