I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This draft describes various ways for RTP applications to keep NAT mappings alive. It goes on to detail individual keepalive methods and advantages/disadvantages of its approach. Intended status of the draft is BCP. I'm not for sure I understand the security considerations section, but I think what it's trying to say is that: old peers, which don't understand the new keepalive message, will appropriately drop the packet sent by its peer? If so then please reword accordingly. No additional security related issues beyond RTP itself discovered in this draft. General comment(s): I appreciate the use of a requirements section, this makes it easier to find out what is or is not in scope for the recommended solutions. Editorial comment(s): Expand the first occurrences of "SDP" and "RTCP". s/needs support/needs to support/ s/mux"attribute/mux" attribute/ Shawn. --