Early Review of draft-ietf-teas-p2mp-loose-path-reopt-07
review-ietf-teas-p2mp-loose-path-reopt-07-rtgdir-early-halpern-2016-11-28-00

Hello,



I have been selected as the Routing Directorate reviewer for this draft. 


The Routing Directorate seeks to review all routing or routing-related 


drafts as they pass through IETF last call and IESG review, and 


sometimes on special request. The purpose of the review is to provide 


assistance to the Routing ADs. For more information about the Routing 


Directorate, please see 


​

http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir








Although these comments are primarily for the use of the Routing ADs, it 


would be helpful if you could consider them along with any other IETF 


Last Call comments that you receive, and strive to resolve them through 


discussion or by updating the draft.




Document: draft-ietf-teas-p2mp-loose-path-reopt-07.txt
Reviewer: Joel M. Halpern
Review Date: 23-November-2016
IETF LC End Date: N/A
Intended Status: Standards Track



Summary: I have some moderate concerns about this document that I think 


should be resolved before publication is approved.




Comments:

Major:


    The use of SHOULD and MAY in section 4.1 seems to lead to a device 


which ostensibly supports this document, but does the wrong things.


    First, with regard to the SHOULDs, in the absence of any indication 


as to why it would not do this, it appears that the SHOULD is really 


"MUST if the device supports this document" which is what MUST in a 


document actually means.


    Section 4.2 first bullet says that a mid-point LSR "SHOULD" check 


for a preferable P2MP-TE LSP Tree.  But if it doesn't, it is not 


supporting this document.  As written, it could decide to ignore the 


message, even though it claims to support this RFC.


    Looking at the handling when a preferable P2MP-TE LSP tree is 


found, according to the document, the LSR MAY send the PathErr response. 


 My assumption is that if it does not send the PathErr, it MUST 


propagate the request.  If it does not do either one, the protocol does 


not function.  It seems likely that if this is really intended to be 


optional (MAY), the document would be improved my giving implementors 


some hint as to when it is desirable or undesirable to send the message.


    Then in the third bullet, it is only a SHOULD to pass on the 


request.  Thus, a device which supports this mechanism, but chooses not 


to pass on the request, is compliant to this document while preventing 


other devices from properly supporting the mechanism.




Minor:


    The abstract is much too long.  Much of the content of the abstract 


belongs in the introduction.  Even teh second paragraph has too much 


detail for an abstract.




Editorial:


    In the last paragraph of the introduction, it says that this 


document "proposes" solutions.  Given we are now in the position of 


evaluating publication as a Proposed Standard, I would say that this 


document "defines" solutions.