This document has been reviewed as part of the transport area review team's ongoing effort to review key IETF documents. These comments were written primarily for the transport area directors, but are copied to the document's authors and WG to allow them to address any issues raised and also to the IETF discussion list for information. When done at the time of IETF Last Call, the authors should consider this review as part of the last-call comments they receive. Please always CC tsv-art@ietf.org if you reply to or forward this review. From a transport perspective, there is one minor issue: Section 7.3 provides a motivation for using a path MTU for IPv4 of 576 bytes. The motivation refers to the requirement that a receiver is capable of receiving IPv4 packets of that size, however they can be received fragmented. While it is acceptable to use 576 bytes as the minimum PMTU, the motivation does not hold.