I've reviewed this document as part of the transport area directorate'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 for their information and to allow them to address any issues
raised. The authors should consider this review together with any other
last-call comments they receive. Please always CC [email protected] if you
reply to or forward this review.
This document is ready to be published. I have one small suggestion. In
Section 3, it reads:
5. PMTUD Failure: A common link MTU size observed on the Internet
today is 1500 bytes. However, when using 6to4 the path MTU is
less than this due to the encapsulation header. Thus a 6to4
client will normally see a link MTU that is less than 1500, but a
native IPv6 server will see 1500. It has been observed that Path
MTU Discovery does not always work, and this can lead to
connectivity failures. Even if a TCP SYN/ACK exchange works, TCP
packets with full size payloads may simply be lost. This problem
is apparently exacerbated in some cases by failure of the TCP MSS
negotiation mechanism. These failures are disconcerting even to
an informed user, since a standard 'ping' from the client to the
server will succeed, because it generates small packets, and the
successful SYN/ACK exchange can be traced. Also, the failure may
occur on some paths but not others, so a user may be able to
fetch web pages from one site, but only ping another.
this would benefit by adding an informational reference to RFC2923, "TCP
Problems with Path MTU Discovery"
-d
