Early Review of draft-ietf-trill-arp-optimization-00
review-ietf-trill-arp-optimization-00-rtgdir-early-gray-2015-06-08-00

Request Review of draft-ietf-trill-arp-optimization
Requested rev. no specific revision (document currently at 09)
Type Early Review
Team Routing Area Directorate (rtgdir)
Deadline 2015-06-08
Requested 2015-06-08
Draft last updated 2015-06-08
Completed reviews Rtgdir Early review of -00 by Eric Gray (diff)
Rtgdir Early review of -05 by Geoff Huston (diff)
Genart Last Call review of -08 by Dale Worley (diff)
Opsdir Last Call review of -08 by Mahesh Jethanandani (diff)
Secdir Last Call review of -08 by Tina Tsou (diff)
Assignment Reviewer Eric Gray
State Completed
Review review-ietf-trill-arp-optimization-00-rtgdir-early-gray-2015-06-08
Reviewed rev. 00 (document currently at 09)
Review result Has Nits
Review completed: 2015-06-08

Review
review-ietf-trill-arp-optimization-00-rtgdir-early-gray-2015-06-08






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-arp-optimization




http://tools.ietf.org/html/draft-ietf-trill-arp-optimization




http://datatracker.ietf.org/doc/draft-ietf-trill-arp-optimization/







Reviewer: Eric Gray




Review Date: 5 June, 2015 




IETF LC End Date: unknown 




Intended Status: Standards Track 




 




Summary: 




I have some minor concerns about this document that I think should be resolved before publication.




 




Comments: 




•Generally, I found this draft to be very well written and easily understandable.





• I had some difficulty in drawing a line between minor comments and NITs in a




    few cases.  I tried to treat comments that were about typos, spelling errors or





    grammar as NITs and other cases where wording choices were ambiguous, or




    potentially misleading as minor comments.  Hopefully the intent of each of my





    comments is clear.







Major Issues: 




•No major issues found. 




 




Minor Issues: 




• I have some difficulty in parsing the second sentence of the first paragraph




   under section 1.1 (Terminology).  What does “listed below for convenience





    with the following along with some additions” mean? 







• The last sentence in the definition of “Campus” adds no value and should be





    removed. The English meaning of Campus includes usages that are not limited




    to schools (which is what I assume you mean in using the term “academic” – as




    opposed to differentiation from “practical” or “commercial”).  For example, a




    corporation or partnership may have more than one campus.





• MAC is an acronym for Media Access Control, which is a link-layer function that




    has an address; “MAC” and “MAC Address” are not synonymous.  You could




    resolve this issue by either removing “address” or putting it in parentheses.





• The definition for RBridge is inadequate as is, because it uses the undefined





    phrase “Routing Bridge.”  This phrase is ambiguous generally (though likely not




    so much in this context) because it could be taken to mean a device that is a




    Bridge with some subset of IP routing capabilities (which isn’t what you mean)




    to differentiate such a device from a Bridging Router (a common capability in




    many – if not most – routers). 




• In Bullet “a.1” in section 3.2 (Determine How to Reply to ARP/ND), “believed”




    is the wrong term.  RBridges – like any other devices – are incapable of having




    beliefs.  Either it “knows” the mapping information required to construct a




    response (through whatever means), or it does not.  As a side note, it might be




    philosophically interesting to define what “belief” means for a device. 


J




• In the next-to-last paragraph of section 3.2, I am pretty sure you want to say




   that encryption 

would

 (as opposed to 




might

) prevent local reply.  That is what




   signing responses is precisely intended to prevent. 







• In section 4, why are the quoted terms “hardware” and “protocol” used?  As




    noted/implied in NITs below, there are many kinds of “hardware” addresses




    and many possible meaning for “protocol” address.  If these are used as they




    are the specific terms used for message content fields, perhaps it would be




    less ambiguous to put IP in parentheses (after “protocol”) and MAC (after




    “hardware”)? 




• In section 5 (Security Considerations), the parenthesized fourth paragraph





    should be removed from parentheses and made a separate paragraph.  The




    potential for use of authentication methods to mitigate risk is an important





    things for a security considerations section to highlight.




 




Nits: 




• Mostly out of curiosity, why define alternative term “TRILL switch” instead of





    simply using one term consistently?  You could simply define an RBridge as a




    device implementing the TRILL protocol and use the term RBridge consistently.




    This approach solves two problems.




• In the definition of the acronym “ND”, “Discoery” should be “Discovery.”





• The word “traditionally” in the first line of section 2 (IP/MAC Address Mappings),




    and “correspondence” in the second line are poor choices.  In the first case, we





    can have no idea what “traditionally” means because there is no “tradition” for




    implementing RBridges.  In the second case, “correspondence” is an ambiguous




    term that is not quite correct in any case.  Also “remote host” should be “remote




    end station” as it is an Ethernet end station that may or may not be a host (it may




    be a router, for example). I recommend rephrasing the entire first sentence as




    “An RBridge (as defined in RFC 6325 and RFC 7172) learns MAC Address and Data





    Label (VLAN or FGL) to nickname mapping information from TRILL data frames it




    receives.”  There has never been anything to prevent an RBridge implementation




    from learning anything that an RBridge implementation might be configured to





    look at. 




• In the second paragraph of section 2, “local hosts” should be “end stations.”





• In the third paragraph of section 2 “examples given above shows” should be





   “examples given above show.” 




• In the second and third bullets of the second paragraph in section 3 (Handling





    ARP/ND Messages), neither “protocol” nor “hardware” are specific enough.  I





    recommend changing the bullets to read “… sender IP/MAC address …” in both




    bullets. 




• In section 3.3 “R2 should initiates” should be “R2 should initiate.”