Reviewer: Robert Sparks Review result: Ready with Nits I am the assigned Gen-ART reviewer for this draft. The General Area Review Team (Gen-ART) reviews all IETF documents being processed by the IESG for the IETF Chair. Please treat these comments just like any other last call comments. For more information, please see the FAQ at <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>. Document: draft-ietf-mpls-residence-time-12 Reviewer: Robert Sparks Review Date: 2017-01-10 IETF LC End Date: 2017-01-17 IESG Telechat date: 2017-02-02 Summary: Ready (with nits) for publication as a Proposed Standard I have two primary comments. I expect both are rooted in the authors and working group knowing what the document means instead of seeing what it says or doesn't say: 1) The document is loose with its use of 'packet', and where TTLs appear when they are discussed. It might be helpful to rephrase the text that speaks of RTM packets in terms of RTM messages that are encoded as G-ACh messages and not refer to packets unless you mean the whole encapsulated packet with MPLS header, ACH, and G-ACh message. 2) Since this new mechanic speaks in terms of fractional nanoseconds, some discussion of what trigger-point you intend people to use for taking the precise time of a packet's arrival or departure seems warranted. (The first and last bit of the whole encapsulated packet above are going to appear at the physical layer many nanoseconds apart at OC192 speeds if I've done the math right). It may be obvious to the folks discussing this, but it's not obvious from the document. If it's _not_ obvious and variation in technique is expected, then some discussion about issues that might arise from different implementation choices would be welcome. The rest of these are editorial nits: It would help to pull an overview description of the difference between one-step and two-step much earlier in the document. I suggest in the overview in section 2. Otherwise, the reader really has to jump forward and read section 7 before section 3's 5th bullet makes any sense. In section 3, "IANA will be asked" should be made active. Say "This document asks IANA to" and point to the IANA consideration section. Apply similar treatment to the other places where you talk about future IANA actions. There are several places where there are missing words (typically articles or prepositions). You're less likely to end up with misinterpretations during the RFC Editor phase if you provide them before the document gets that far in the process. The spots I found most disruptive were these (this is not intended to be exhaustive): Section 3: "set 1 according" -> "set to 1 according" Section 3: "the Table 19 [IEEE..." -> "Table 19 of [IEEE..." Section 4.2: "Detailed discussion of ... modes in Section 7." -> "Detailed discussion of ... modes appears in Section 7." Section 10: "most of" -> "most of all" In Setion 3.1 at "identity of the source port", please point into the document that defines this identity and its representation. I suspect this is a pointer into a specific section in IEEE.1588.2008].