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Early Review of draft-ietf-spring-srv6-srh-compression-16

Request Review of draft-ietf-spring-srv6-srh-compression
Requested revision No specific revision (document currently at 17)
Type Early Review
Team Ops Directorate (opsdir)
Deadline 2024-04-19
Requested 2024-03-21
Requested by Joel M. Halpern
Authors Weiqiang Cheng , Clarence Filsfils , Zhenbin Li , Bruno Decraene , Francois Clad
I-D last updated 2024-05-14
Completed reviews Intdir Early review of -17 by Benson Muite
Rtgdir Early review of -16 by Nicolai Leymann (diff)
Opsdir Early review of -16 by Gyan Mishra (diff)
This draft is in working group last call, with a small number of issues still being discussed.  The content is alrgely stable, so review at this stage would be helpful.
Assignment Reviewer Gyan Mishra
State Completed
Request Early review on draft-ietf-spring-srv6-srh-compression by Ops Directorate Assigned
Posted at
Reviewed revision 16 (document currently at 17)
Result Ready
Completed 2024-05-14
I have reviewed the latest version 16 of the draft with Operational
Considerations section 9.3 added to address L4 checksum discussion on ML. The
draft is well written and is ready for publication.

I have been following the ML thread since it began related to L4 checksum.  The
key here for operators deploying c-SID SRv6 Compression Next SID is that
endpoints performing L4 checksum would not exist on the SRv6 network closed
domain and would exist within the customer payload which remains unaltered and
will always pass the L4 checksum.  Section 9.3 addresses the operational
consideration where the DA is not the same as the final destination and may
require enhancements to convey the final destination address.

Section 9.3
Upper layer checksums are computed by the originator of an IPv6 packet and
verified by the ultimate destination(s) as it processes the upper layer

As specified in Section 6.5, SR source nodes originating TCP/UDP packets ensure
that the upper layer checksum is correctly calculated based on the ultimate
destination of the session, which may be different from the address placed in
the IPv6 destination address. Such SR source nodes leveraging TCP/UDP offload
engines may require enhancements to convey the ultimate destination address.
These implementation enhancements are outside the scope of this document.

Middleboxes such as packet sniffers, if deployed inside the SR domain, may fail
to verify the upper layer checksum of transit SRv6 traffic. Making these
middleboxes SRv6 aware in general or C-SID aware in particular is out of the
scope of this document.

Major issues:

Minor issues: