Subject: [Dime] Clarification: ABNF for error messages ?

From: Sebastien Decugis <[email-masked]>
Date: Tue, 08 Dec 2009 17:17:32 +0900

Hello all,

RFC3588 section 7.2 (and still in bis document) requires an answer
message to conform to its ABNF, unless the E bit is set, in which case
the ABNF may be different.
I would like to point that this requirement cannot always be satisfied,
for example when the Result-Code is being set to
DIAMETER_COMMAND_UNSUPPORTED in which case the local peer does not know
anything about the ABNF.

I am wondering if the correct behavior would be to set the E bit for
this Result-Code value (in which case a relay would try to send it to an
alternate peer) or assume that the ABNF has to be checked only in case
of Success (2xxx) and Informational (1xxx) Result-Code values ? Does
someone have any comment on this ?

Thank you in advance.
Best regards,
Sebastien.

-- 
Sebastien Decugis
Research fellow
Network Architecture Group
NICT (nict.go.jp)