[Idr] Re: New Version Notification for draft-ali-idr-srv6-policy-sid-list-optimization-00.txt

["Zafar Ali (zali)" <[e-mail]>]

Hi Cheng Li,

Thanks for your review.
Please see [ZA] in-line.

Thanks

Regards … Zafar

From: Cheng Li <[e-mail]>
Date: Thursday, October 31, 2024 at 12:05 PM
To: Zafar Ali (zali) <zali=[e-mail]>, [e-mail] <[e-mail]>
Cc: Zafar Ali (zali) <[e-mail]>
Subject: RE: New Version Notification for draft-ali-idr-srv6-policy-sid-list-optimization-00.txt
Hi Zafar,

I have reviewed the draft, which is short but very useful, and also good as a 00 revision draft.

Some comments here.

We need to add the N-flag in the Segment list level as well. Because whether an endpoint node SID can be excluded depends on the SID of a Segment list, instead of the candidate path or a policy. Sure, if all the Segment lists can meet the requirement of excluding the last node SID, then the flag can be set in the candidate path level. Same logic for the BSID in a SR policy. This also apply to the PCEP extension draft. https://datatracker.ietf.org/doc/html/draft-ali-pce-srv6-policy-sid-list-optimization-00.



[ZA] I see the inclusion/ exclusion of endpoint node SID flag as an SR policy attribute (hence kept at the CP level).
The idea is to control the inclusion or exclusion of the Policy Endpoint node SID depending on the type of “traffic steered over the policy”.
As this flag controls the steering aspects, all SLs should get the same treatment.
For example:

·         If a VPN service is carried over an SR policy, the endpoint node SID should be excluded for all SLs of a CP to ensure it remains efficient for all the SLs.

·         Similarly, if MPLS traffic is carried over an SR policy, the endpoint node SID should be included for all SLs of a CP to ensure the data plane at Egress is not broken for all the SLs.



In Introduction,

“ The SRv6 policy SID list may end with the policy endpoint's Node SID
   or the penultimate hop adjacency SID.”

I think this logic is correct. We need to consider the END.X SID(pointing to the egress node) as well. Hope to highlight this in the document.
The logic should be: if a segment list points to the egress node, then the redundant node SID or the node C-SID(node ID) of VPN SID should be removed.

[ZA] I agree –

[ZA] Thanks for the collaboration and we can add some clarification text for both comments in the upcoming revision.

Thanks,
Cheng




From: Zafar Ali (zali) <zali=[e-mail]>
Sent: Tuesday, October 22, 2024 6:16 AM
To: [e-mail]
Cc: Zafar Ali (zali) <[e-mail]>
Subject: [Idr] FW: New Version Notification for draft-ali-idr-srv6-policy-sid-list-optimization-00.txt

Hi,

We have posted a draft that addresses use cases in which the SRv6 policy's SID list ends with the policy endpoint's node SID, and the traffic steered (over policy) already ensures that it is taken to the policy endpoint.
Draft: https://datatracker.ietf.org/doc/draft-ali-idr-srv6-policy-sid-list-optimization/
We would like to solicit your feedback on the draft.

Thanks

Regards … Zafar

From: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Date: Monday, October 21, 2024 at 4:36 PM
To: Rajesh M Venkateswaran <[e-mail]<mailto:[e-mail]>>, Rajesh Venkateswaran <[e-mail]<mailto:[e-mail]>>, Zafar Ali (zali) <[e-mail]<mailto:[e-mail]>>
Subject: New Version Notification for draft-ali-idr-srv6-policy-sid-list-optimization-00.txt
A new version of Internet-Draft
draft-ali-idr-srv6-policy-sid-list-optimization-00.txt has been successfully
submitted by Zafar Ali and posted to the
IETF repository.

Name:     draft-ali-idr-srv6-policy-sid-list-optimization
Revision: 00
Title:    BGP SRv6 Policy SID List Optimization
Date:     2024-10-21
Group:    Individual Submission
Pages:    5
URL:      https://www.ietf.org/archive/id/draft-ali-idr-srv6-policy-sid-list-optimization-00.txt
Status:   https://datatracker.ietf.org/doc/draft-ali-idr-srv6-policy-sid-list-optimization/
HTMLized: https://datatracker.ietf.org/doc/html/draft-ali-idr-srv6-policy-sid-list-optimization


Abstract:

   In some use cases, an SRv6 policy's SID list ends with the policy
   endpoint's node SID, and the traffic steered (over policy) already
   ensures that it is taken to the policy endpoint.  In such cases, the
   SID list can be optimized by excluding the endpoint Node SID when
   installing the policy.  This draft specifies a BGP extension to
   indicate whether the endpoint's node SID needs to be included or
   excluded when installing the SRv6 Policy.



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