Now to answer your other questions...
On 07-Mar-26 20:10, 杜林潼 wrote:
...
We do have a couple of questions where your guidance would be
particularly helpful:
1. In our design, the Path Initiator needs to distribute different
node-protection-info to each node along the primary path (each
node receives its own role, upstream/downstream neighbors, and
backup path if applicable). We are using individual GRASP
negotiation sessions for this. Would you consider this the
idiomatic way to use GRASP for such per-node configuration, or
would you suggest an alternative approach such as using flood
with filtering?
Unless there is a performance problem, I believe that separate
negotiations are better. Of course, if you were dealing with hundreds
of nodes my answer might be different. It might be worth designing
your objectives so that they can used in both models.
I think that flooding plus filtering can get very complicated, however.
https://www.ietf.org/archive/id/draft-ietf-anima-grasp-distribution-12.html
shows the complexity.
2. For the SRv6 operational details — the bounce-back strategy is
essentially a data plane fast reroute mechanism that works in
two phases: (a) in-flight packets are bounced upstream to the
nearest Anchor node upon failure detection, and (b) the Anchor
node re-encapsulates them onto a pre-computed backup SRv6 path.
GRASP is only used during the setup phase to distribute the
protection state, not during the actual failover. We would be
happy to provide a more detailed explanation of the SRv6 aspects
if that would be helpful.
That sounds correct to me. GRASP was not designed for high performance;
it should not be expected to react at light speed to faults.
We will share our graspy-based simulation results once the prototype
is ready. Thank you again for your encouragement and the excellent
graspy tool.
That will be great. Don't hesitate to report any bugs you find!
Regards
Brian
Best regards,
Lintong Du
(on behalf of all co-authors)
Beijing University of Posts and Telecommunications
杜林潼
北京邮电大学/研博生/计算机学院（国家示范性软件学院）
北京
------------------ Original ------------------
*From:* "Brian E Carpenter";
*Date:* 2026年3月7日(星期六) 上午6:32
*To:* "Anima WG"; "draft-du-anima-srv6-failover-grasp";
*Subject:* Re: I-D Action: draft-du-anima-srv6-failover-grasp-00.txt
Hi,
I had a quick look at this draft and so far its definition of a GRASP objective
looks correct to me. I don't understand SRV6 operations well enough to comment
on the details of the use case.
I'll just remind the authors that they could simulate the use case using the
demonstration implementation of of GRASP, open source at
https://github.com/becarpenter/graspy/ <https://github.com/becarpenter/graspy/>
Regards/Ngā mihi
Brian Carpenter
On 02-Mar-26 03:21, [email protected] <mailto:[email protected]>
wrote:
> Internet-Draft draft-du-anima-srv6-failover-grasp-00.txt is now available.
>
> Title: Autonomic SRv6 Network Fast Failover Using Bounce-back Strategy
with GRASP
> Authors: Lintong Du
> Xiangyang Gong
> Xirong Que
> Fang Deng
> Name: draft-du-anima-srv6-failover-grasp-00.txt
> Pages: 15
> Dates: 2026-03-01
>
> Abstract:
>
> This document specifies an autonomic fast failover mechanism for SRv6
> networks using a bounce-back strategy. It uses GRASP to distribute
> failover protection information, enabling data plane fast reroute
> without control plane reconvergence.
>
> The IETF datatracker status page for this Internet-Draft is:
> https://datatracker.ietf.org/doc/draft-du-anima-srv6-failover-grasp/
<https://datatracker.ietf.org/doc/draft-du-anima-srv6-failover-grasp/>
>
> There is also an HTML version available at:
> https://www.ietf.org/archive/id/draft-du-anima-srv6-failover-grasp-00.html
<https://www.ietf.org/archive/id/draft-du-anima-srv6-failover-grasp-00.html>
>
> Internet-Drafts are also available by rsync at:
> rsync.ietf.org::internet-drafts
>
>
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