Re: [mpls] MPLS-RT experts review for draft-gandhi-mpls-rfc6374-sr

[Yimin Shen <[e-mail]>]

Hi WG,

I was assigned as a reviewer for draft-gandhi-mpls-rfc6374-sr. I have now completed my review.

The document addresses packet loss and delay measurement for SR-MPLS, by building it on top of the mechanism specified by RFC 6374. This is a useful feature. The document is coherent and technically sound. I think it is ready for WG adoption.

In the meanwhile, I do have a few questions and comments, and hope they could be addressed by the authors.

[1] The document uses terms “SR link(s)” and “SR-MPLS link(s)” interchangeably. I’d like to suggest to change “SR link(s)” to “SR-MPLS link(s)”, for consistency and also as “SR links” include SRv6 links which are out of the scope.

[2] The term “SR-MPLS links” needs further clarification. Does it mean MPLS links (in an SR-MPLS environment), or there is something more specific ? Either case, please clarify whether the procedures for “SR-MPLS links” in this document are actually the same as those for MPLS links in RFC 6374, or high light the changes explicitly.

[3]  In sections 4.4 and 6.2, respectively:


   The Return Path TLV is Mandatory when used.  If responder does not

   support this TLV, it MUST return Error 0x17: Unsupported Mandatory

   TLV Object.

   The Block Number TLV is Mandatory when used.  If responder does not
   support this TLV, it MUST return Error 0x17: Unsupported Mandatory
   TLV Object.

Is it mandatory that both the sender and the responder must support this document ? Is it possible for a sender (supporting the document) to inter-op with a responder supporting only RFC 6374, i.e. a mixed mode ? If the mixed mode is allowed, it would deserve some text (or a section) to explain and clarify the procedures and applicabily.

Thanks,

-- Yimin Shen
Juniper Networks


From: Tarek Saad <[e-mail]>
Date: Wednesday, May 6, 2020 at 10:46 AM
To: Yimin Shen <[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
Cc: "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: MPLS-RT experts review for draft-gandhi-mpls-rfc6374-sr

[External Email. Be cautious of content]

Yimin, Xufeng, and Huaimo,

You have be selected as MPLS-RT reviewers for draft-gandhi-mpls-rfc6374-sr.

Note to authors: You have been CC'd on this email so that you can know that this review is going on. However, please do not review your own document.

Reviews should comment on whether the document is coherent, is it useful (ie, is it likely to be actually useful in operational networks), and is the document technically sound?  We are interested in knowing whether the document is ready to be considered for WG adoption (ie, it doesn't have to be perfect at this point, but should be a good start).

Reviews should be sent to the document authors, WG co-chairs and WG secretary, and CC'd to the MPLS WG email list. If necessary, comments may be sent privately to only the WG chairs.

If you have technical comments you should try to be explicit about what *really* need to be resolved before adopting it as a working group document, and what can wait until the document is a working group document and the working group has the revision control.

Are you able to review this draft by May 20, 2020? Please respond in a timely fashion if you cannot make it.

Regards,
Tarek
(as MPLS WG chair)


Juniper Business Use Only