[mpls] AD review of draft-ietf-mpls-rsvp-te-no-php-oob-mapping-07
Adrian Farrel <Adrian.Farrel@huawei.com> Sat, 23 April 2011 13:48 UTC
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Date: Sat, 23 Apr 2011 14:48:51 +0100
From: Adrian Farrel <Adrian.Farrel@huawei.com>
To: draft-ietf-mpls-rsvp-te-no-php-oob-mapping@tools.ietf.org
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Subject: [mpls] AD review of draft-ietf-mpls-rsvp-te-no-php-oob-mapping-07
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Hi, Don't panic! I have performed my AD review of your draft. The purpose of the review is to catch any nits or issues before the document goes forward to IETF last call and IESG review. By getting these issues out at this stage we can hope for a higher quality review and a smoother passage through the process. I found number of small issues and questions. These are mainly concerns with clarity, and editorial issues. All of my comments are up for discussion, and you should not feel rail-roaded into making changes. But I do think my comments need to be addressed before this document is presented for IETF last call, and I would like you to have a look and see whether you can work to improve the text before I take it forward. I have moved the draft into "AD-review:Revised-ID-needed" state in the datatracker, and I look forward to seeing the new revision which I can put forward for IETF last call. Thanks, Adrian --- It would be best to expand the acronyms PHP and LSP in the document title. --- Acronyms need to be expanded on first use in the main body of the text. The Abstract should be seen as stand-alone, and you have to start expanding them again. I find: RSVP-TE MVPN VPLS LSR LSP --- Please decide between "out-of-band" and "out of band" and update the document accordingly. --- Abstract s/proposes/defines/ --- Section 2.1 When signaling a P2MP LSP, a source node may wish to solicit individual response to "non-PHP behavior flag" from the leaf nodes. Given the constraints on how the LSP_ATTRIBUTES may be carried in Path and Resv Messages according to RFC5420, in this situation a source node MUST use a separate Path message for each leaf. This is wrong, isn't it? P2MP signaling is defined in RFC 4875. That document clearly describes how LSP_ATTRIBUTES are used in the P2MP case. You have the RRO flags available to record egress LSR behavior. The same issue arrises in Section 2.2. --- Section 2.1 If the egress LSR - supports the LSP_ATTRIBUTES object but does not recognize the Attributes Flags TLV; or - supports the LSP_ATTRIBUTES object and recognize the Attributes Flags TLV, but does not recognize "non-PHP behavior flag"; then it SHOULD silently ignore this request. The behavior in these two cases is not something you can define here since such LSRs will not be conformant to this document. Fortunately, this behavior is defined in RFC 5420, so you can re-write as: then it will silently ignore this request according to the processing rules of [RFC5420]. The same applies in Section 2.2 --- Section 2.2 I had a bit an "I wouldn't have done it this way" moment. Can you explain why you opted for a mechanism that signals the fact that another mechanism will be used to bind LSPs, rather than enhancing RSVP-TE to actually signal the use? Actually, RSVP-TE already includes mechanisms that could very easily have carried the binding information. Obviously you need to support existing non-RSVP mechanisms, but that could have been rolled in. --- Section 2.4 It would be interesting to know whether OAM is expected to work or not while the egress is black-holing data pending binding. --- Section 3 Since you have introduced a dependence on an external communications method, you have also introduced a new security consideration. You have also introduced some new vectors that can be used to attack the LSP. For example, changing the label reported in the RRO can cause it to be torn down. Although this does not change the overall security model or techniques, it should be pointed out so that an operator can consider the additional pressure to apply adequate security mechanisms. You should include a reference to RFC 5920. --- Section 4 You are missing a subsection header 4.2. New RSVP Return Code --- Section 4.1 Please remove suggested values from this section and the whole document. You will notice that flag 6 has already been assigned. Including suggested values in a draft is only likely to result in confusion. --- Section 4.1 o These flags are to be used in the Attributes Flags TLV in both Path and Resv messages. Please be more explicit so that IANA can fill in the table at http://www.iana.org/assignments/rsvp-te-parameters The easiest is to supply all the table entries except for the TBD values. ---
- [mpls] AD review of draft-ietf-mpls-rsvp-te-no-ph… Adrian Farrel