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-trill-directory-assist-mechanisms​-03.txt 




Reviewer: Matthew Bocci 




Review Date: July 2015 




IETF LC End Date: Unknown 




Intended Status: Proposed Standard










Summary: 




I have some minor concerns about this




document that I think should be resolved before publication. 










Comments:










The draft is mostly ready for publication, but I have some comments related to




which procedures are mandatory to implement, and which are optional (see minor




issues below). I've flagged this because in my experience 




it is very important for an RFC to be crystal clear about what is mandatory for 




successful interoperability.






















Major Issues:










No major issues.










Minor Issues:













In general, it is very unclear if it is mandatory to implement both push and pull, 




or if it is adequate to just implement one or the other. I appreciate that a hybrid




mode is possible, in which case an implementation would need to support both, but 




this is only described at the end in section 4, almost as an afterthought. It would 




be much better if the draft could be clear up-front which is the mandatory (default)




mode, or if both must be implemented if the expectation is that the default operating




model is hybrid.













Section: "1. Introduction"




1st Paragraph: Last sentence




"These mechanisms are optional to implement." 




This statement seems redundant, since technically the whole RFC is optional 




unless another RFC makes a normative reference to it :) I think you should either




remove this statement, or use it to clarify which modes are optional and which are 




mandatory.










Pg14:




"If information previously




   pulled is about to expire, a TRILL switch MAY try to refresh it by




   issuing a new pull request but, to avoid unnecessary requests, SHOULD




   NOT do so if it has not been recently used."




   




Can you give more information on what you mean by "recently"? Some non-normative 




guidance might be helpful to prevent wildly differing or unpredictable behaviours 




in a multi-vendor deployment.   




   




Nits:










- There are a few uncommon acronyms. Please expand all acronyms on first use.




- Pg4 s/MacDA/MAC DA




- Pg8 s/angel bracket/angle bracket