I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, please see the FAQ at < http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. Please resolve these comments along with any other Last Call comments you may receive. Document: draft-ietf-mmusic-latching-05.txt Reviewer: Elwyn Davies Review Date: 27 May 2014 IETF LC End Date: 28 May 2014 IESG Telechat date: 29 May 2014 Summary: Ready with nits. Generally a well argued document. In the light of the comment that the IETF advises the use of ICE or STUN rather than HNT, I wondered if it might be helpful to explain how these mechanisms mitigate or resolve the security issues in s5. Major issues: None Minor issues: s5: Section 4 talks about problems with XMPP but the security concerns in s5 are all discussed in the context of SIP/SBC. I think some words about the corresponding security issues in XMPP (or just a statement that all - or a subset - of these apply to XMPP) ought to be added. s8: Barry Leiba in his comments in the tracker suggests that the references would be usefully split into Normative and Informative subsets. Given the number of references, splitting them up seems like a good idea. I am going to suggest something highly heretical: Split them up but call them "Key References" and "Additional References". "Normative" has become such a loaded word in the standards community that, despite its underlying English meaning, it is probably better to confine its usage to Standards Track documents. I feel that we usefully adopt this alternative classification for non-standards track documents as a general technique to avoid the ongoing discussions about split refetrence sections. Nits/editorial comments: General: Would probably be useful to explain the "address:port" terminology; Also both the terms "couple" and "set" are used for the tuple - better to stick with one and use "address:port sets/couples" instead of "address:ports". General: s/e.g./e.g.,/g s1: Need to expand SDP s3, last sentence: OLD: the SBC may decide not to send media to that customer UA until a SIP 200 response for policy reasons, to prevent toll-fraud. NEW: the SBC may decide, for policy reasons, not to send media to that customer UA until a SIP 200 response has been received, [e.g., ???] to prevent toll-fraud. s4, para 1: s/ address:port set that once packets cross the NAT, will be mapped/address:port set that, once packets cross the NAT, will be mapped/ s4, Figure 2: The figure doesn't reflect the address mapping done in the NATs. the clients Alice and Bob are shown with public (documentation) addresses whereas they should presumably have private addresses that are mapped to these public addresses by the NAT. s4, Figure 3: The previous comment doesn't apply to this figure which shows the NAT mapping. Arguably it would be nice to use private address space addresses on the private side of the NAT, but I notice we never managed to allocate a specific private address for documentation - I suppose since they are private it doesn't matter! s4, Figure 3, title: Cut and paste error... this figure is about XMPP not SBC! s5, para 2: s/In all/All/