I guess I have to ask again. Can the RFC4890 authors please
comment on the RFC4890, Section A.2 text questions asked in
my previous message (below)?
Fred
fred.l.templin@boeing.com
-----Original Message-----
From: Templin, Fred L
Sent: Thursday, June 04, 2009 8:44 AM
To: Mohacsi Janos; Brian E Carpenter
Cc: JiangSheng 66104; Seiichi Kawamura; Gert Doering; Fleischman,
Eric; Re'mi Despre's;
v6ops@ops.ietf.org; guoseu@huawei.com; Russert, Steven W
Subject: RE: New Version Notification for
draft-jiang-v6ops-incremental-cgn
Do you think the draft needs to do any more than recommending to
follow
the recommendations in 4890? It seems as if that should be
sufficient.
This should be enough.
Regarding the 4890, there is advice in that document that I
would like to understand better. In Appendix A.2, it says:
"If a network chooses to generate packets that are no larger than
the
Guaranteed Minimum MTU (1280 octets) and the site's links to the
wider Internet have corresponding MTUs, Packet Too Big messages
should not be expected at the firewall and could be dropped if they
arrive."
But, that would seem to be in conflict with the text of
Section 5 of RFC2460, where the reader is informed that
the network can return PTB messages reporting MTU values
smaller than 1280 if a protocol translator is in the path.
The host should then react to these PTBs by inserting a
fragment header with (MF=0; Offset=0) in subsequent packets.
With the (RFC4890, Appendix A.2) text however, this behavior
is suppressed.
Where did the RFC4890 text come from? And, why is it there?
Thanks - Fred
fred.l.templin@boeing.com