Re: [Srcomp] Draft Minutes Oct 14

["Darren Dukes (ddukes)" <[e-mail]>]

Hi Peng, please see inline [DD]



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Subject: Re: [Srcomp] Draft Minutes Oct 14



Hi Team,


I don't know if it's appropriate to discuss more about this on-line. If not, I'm sorry.


For section 4.1.1, IMO, both RFC8754 (SRH) and PGM are exactly defined for classical SRv6, just referring to the pseudo code of each type of SID. I think it is strange to emphasize to comply with those documents for CompSRv6, can we describe what details must be compliant with ?


[DD] - Since the objective is to compress SRv6 encapsulation, it's important to understand if a proposal is complying with, extending, or redefining the SRv6 specifications to provide that compression.



For section 4.1.8, I'm also confused about it. I don't think there is such a thing as segment summarization, up to now I don't see a summarized segment is contained in a segment list.


[DD] Think of IPv6 address summarization.  As you know one big advantage of SRv6 (with IPv6 SIDs) over MPLS is IPv6 address summarization.  I can advertise a summarized route from one area or domain to another without advertising every 128bit SID.  In SRv6, this allows an SR source node to create a segment list where a single segment can traverse multiple areas/domains thanks to IPv6 address summarization.



The individual segments (instead of summarized segments) must be advertised and collected in link-state database maintained on headend or controlloer, and used in the computed SR path later. Are you exactly talking about route aggregation ? If yes, please call it route aggregation. As far as I know, for inter-domain case the computed path will certainly include the border nodes, according to the methods described in RFC5152, RFC5441, RFC6805.


Regards,

PSF



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SRCOMP Minutes Oct 14



Topics:

HETEROGENEOUS SID LISTS

  *   Ron proposes this is out of charter

  *   Weiqiang requested that Ron and Darren discuss offline



Section 4.1 review

  *   Section 4.1.1

     *   Ron proposed to not include drafts not past WGLC

        *   Some expressed these drafts also describe desired functionality

        *   No conclusion

     *   Ron proposed that this requirement is not in scope

        *   disagreement was expressed

        *   No action to take

     *   Some noted that we are concerned with support of functionality

        *   The functionality specified by SPRING, and these documents, and compliance to it is an easy indication of support

     *   Proposal: table with functionality or RFC/draft was discussed

        *   Discussion about how to build such a table was had

     *   Request to differentiate between functionality and architecture in requirements

        *   Wim noted that it is important to identify when functionality is provided with current architecture

     *   ACTION: Weiqiang requested proposals for this section, offline discussion to be had and proposals posted.



  *   Section 4.1.2

     *   Team is OK with segment length

     *   Wim noted that any segment type should be supported and we had a requirement for this ¨C

        *   ACTION Wim to track that down and make sure it¡¯s covered

  *   Section 4.1.8

     *   Ron suggested no benefit in single domain

     *   Rationale suggestion:

        *   Keep first sentence then...

        *   This provides benefit in interdomain deployments

        *   In interdomain deployments any node can reach any other node via a single prefix segment

        *   Without summarization border router SIDs must be leaked and any node can reach any other node via two global prefix segments.

     *   Proposed metric text was given in the call:

        *   When the SR domain is divided into multiple IGP domains or levels segments can be summarized for advertisement into other domains or levels.

     *   ACTION: Darren to publish an update considering proposals above.