Re: [spring] I-D Action: draft-lin-sbfd-path-consistency-over-srv6-02.txt

linchangwang <> Tue, 16 August 2022 12:17 UTC

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From: linchangwang <>
To: Reshad Rahman <>, "" <>, "" <>, "" <>
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Thread-Topic: I-D Action: draft-lin-sbfd-path-consistency-over-srv6-02.txt
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Subject: Re: [spring] I-D Action: draft-lin-sbfd-path-consistency-over-srv6-02.txt
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Hi Reshad,

Thank you for your reply.

BFD message is usually processed by dedicated CPU or directly at hardware level to realize fast-path forwarding function.
For programmable NP or switching chip, BFD return-path finding and forwarding function can be realized in fast-path without affecting BFD performance.

Changwang lin

From: Reshad Rahman []
Sent: Friday, August 12, 2022 10:37 PM
To:;;; linchangwang (RD)
Subject: Re: I-D Action: draft-lin-sbfd-path-consistency-over-srv6-02.txt


Thanks for addressing my comments on -00.

My only technical comment is that on the reflector there is now lookup to be done to craft the response packet baased on the packet sent by the initiator. I believe this is "unusual" in BFD, not saying it is wrong (not yet anyway...). And it has the impact that it could be difficult to do responder functionality in "fast-path".


On Tuesday, July 12, 2022, 10:41:29 AM EDT, linchangwang <> wrote:

Hi WG & Chairs

  We updated the draft: draft-lin-sbfd-path-consistency-over-srv6-02.

  This draft describes the method of keep the path consistency of sbfd in detecting SRv6 policy through Path Segment,

  and this draft has been presented at the spring meeting of IETF113.

  The new version modified the description of sbfd packet encapsulation refer to [draft-liu-bfd-srv6-policy-encap].

  Any comments on the draft are welcome.


  Changwang lin

-----Original Message-----
From: I-D-Announce [<>] On Behalf Of<>
Sent: Monday, July 11, 2022 2:03 PM
Subject: I-D Action: draft-lin-sbfd-path-consistency-over-srv6-02.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.

        Title          : S-BFD Path Consistency over SRv6
        Authors        : Changwang Lin
                          Weiqiang Cheng
                          Wenying Jiang
  Filename        : draft-lin-sbfd-path-consistency-over-srv6-02.txt
  Pages          : 12
  Date            : 2022-07-10

  Bidirectional Forwarding Detection (BFD) can be used to monitor
  paths between nodes. Seamless BFD (S-BFD) provides a simplified
  mechanism which is suitable for monitoring of paths that are setup
  dynamically and on a large scale network. In SRv6, when a headend
  use S-BFD to monitor the segment list/CPath of SRv6 Policy, the
  forward path of control packet is indicated by segment list, the
  reverse path of response control packet is via the shortest path
  from the reflector back to the initiator (headend) as determined by
  routing. The forward path and reverse path of control packet are
  likely inconsistent going through different intermediate nodes or
  links. This document describes a method to keep the forward path and
  reverse path of S-BFD consistent when detecting SRv6 Policy.

The IETF datatracker status page for this draft is:

There is also an htmlized version available at:

A diff from the previous version is available at:

Internet-Drafts are also available by rsync at

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