Re: [Dime] RFC 3588 - fixed positioned session-ID AVPs

["Glen Zorn" <[e-mail]>]

David Lehmann [mailto:[e-mail]] writes:
Glen,

 

That is not what the spec says.  

Actually, it's exactly what the spec says; please revisit RFC 2119 for the
definition of the key word "SHOULD".

At least, the wording is not clear and, IMHO, is misleading.  In which "some
message" can the session-id AVP be in any position?

Sorry, maybe I was unclear.  Let me try again: the definition of the
Session-Id AVP does not preclude the definition of a Diameter message in
which the Session-Id AVP does not immediately follow the Diameter header;
that (AFAIK) no such message currently exists is irrelevant.

It seems to me that the wording in section 8.8 should be:  "When present,
the Session-Id MUST appear immediately following the Diameter Header (see
Section 3)."

Why unnecessarily constrain the reuse of the AVP?

--

David Lehmann

Ulticom, Inc.

856-787-2952

 

From: Glen Zorn [mailto:[e-mail]] 
Sent: Tuesday, August 31, 2010 9:54 AM
To: David Lehmann
Cc: [e-mail]
Subject: RE: [Dime] RFC 3588 - fixed positioned session-ID AVPs

 

David Lehmann  <mailto:[mailto://[e-mail]%5d>
[mailto://[e-mail]] writes:













 
Hello,
Hello.
In RFC 3588 (and 3588bis), messages with session IDs are defined with the
session ID AVPs with a fixed position which is immediately following the
header. (e.g. section 8.3.1)  
Yes.
However, this is in contradiction with section 8.8 which states, "When
present, the Session-Id SHOULD appear immediately following the Diameter
Header (see Section 3)."
No.
By using "SHOULD", the spec is stating that the session-ID AVP could be in
any position in the message.

No, it is stating that the AVP could be in any position in some message.
The syntax of the existing messages in RFC 3588 is defined by the associated
BNF and in those messages the Session-Id AVP must immediately follow the
Diameter header.

 

 

Hope this helps.

 

 ~gwz