Subject: [Teas] RtgDir review: draft-ietf-teas-p2mp-loose-path-reopt-07.txt

From: "Joel M. Halpern" <[email-masked]>
Date: Wed, 23 Nov 2016 16:10:27 -0500

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.