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

Its good to have some clarity, though the statement below probably needs
some re-org since SHOULD is followed with a MUST and theres a
conditional 'may' in between. Anyway, the statement maybe redundant
since each BNF already tells you where the session-id can be found ..

my 2 cents.

On Wed, Sep 1, 2010 at 8:55 AM, David Lehmann <dlehmann@ulticom.com> wrote:

>  OK, BNF rules.    IMHO, this should be noted or clarified in section 8.8.
> e.g.
>
> “When present, the Session-Id SHOULD appear immediately following the
> Diameter Header. Further, the message BNF may mandate that the Session-Id
> MUST be positioned immediately following the message header.  Indeed, all
> messages defined in this RFC require such a positioning. (see Section 3)”
>
>
>
> --
>
> *David Lehmann*
>
> Ulticom, Inc.
>
> 856-787-2952
>
>
>
> *From:* Victor Fajardo [mailto:vf0213@gmail.com]
> *Sent:* Tuesday, August 31, 2010 4:25 PM
>
> *To:* David Lehmann
> *Cc:* Glen Zorn; dime@ietf.org
> *Subject:* Re: [Dime] RFC 3588 - fixed positioned session-ID AVPs
>
>
>
> yes. the BNF sets the positioning/sequencing rules. it's a common
> practice in BNFs to place session-id near the head to optimize msg
> processing .. etc.
>
> On Tue, Aug 31, 2010 at 3:22 PM, David Lehmann <dlehmann@ulticom.com>
> wrote:
>
> So you are stating that the Diameter protocol itself does NOT require all
> session-ID AVPs to follow immediately after the message header, but a
> message’s BNF may require it?
>
>
>
> --
>
> *David Lehmann*
>
> Ulticom, Inc.
>
> 856-787-2952
>
>
>
> *From:* Victor Fajardo [mailto:vf0213@gmail.com]
> *Sent:* Tuesday, August 31, 2010 2:21 PM
>
>
> *To:* David Lehmann
> *Cc:* Glen Zorn; dime@ietf.org
> *Subject:* Re: [Dime] RFC 3588 - fixed positioned session-ID AVPs
>
>
>
>
>
> On Tue, Aug 31, 2010 at 1:54 PM, David Lehmann <dlehmann@ulticom.com>
> wrote:
>
> The existing text in 8.8 is contradicting the BNF.
>
>
>
>
>
> Which BNF though ? There maybe apps beyond 3588 that may not necessarily
> put the session-id after the header in their BNF's. In that regard, the
> existing text is not contradictory but is meant to be generalized specially
> because it describes an AVP and is agnostic to any BNF.
>
>
>
> my two cents,
>
> victor
>
>
>
>
>
>  I am suggesting text that agrees and supports the BNF.
>
>
>
> If you don’t want to modify the text to agree with the BNF, then I suggest
> removing the existing text which contradicts it.
>
>
>
> --
>
> *David Lehmann*
>
> Ulticom, Inc.
>
> 856-787-2952
>
>
>
> *From:* Victor Fajardo [mailto:vf0213@gmail.com]
> *Sent:* Tuesday, August 31, 2010 11:52 AM
> *To:* David Lehmann
> *Cc:* Glen Zorn; dime@ietf.org
> *Subject:* Re: [Dime] RFC 3588 - fixed positioned session-ID AVPs
>
>
>
> Hi David,
>
> On Tue, Aug 31, 2010 at 10:37 AM, David Lehmann <dlehmann@ulticom.com>
> wrote:
>
> Glen,
>
>
>
> That is not what the spec says.  At least, the wording is not clear and,
> IMHO, is misleading.  In which “*some* message” can the session-id AVP be
> in any position?
>
>
>
> 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).”
>
>
>
> As Glen has mentioned, the BNF dictates the positioning of the AVP. If you
> add this text you are adding new rules beyond the BNF.
>
>
>
> regards,
>
> victor
>
>
>
>
>
>
>
>
>
> --
>
> *David Lehmann*
>
> Ulticom, Inc.
>
> 856-787-2952
>
>
>
> *From:* Glen Zorn [mailto:gwz@net-zen.net]
> *Sent:* Tuesday, August 31, 2010 9:54 AM
> *To:* David Lehmann
> *Cc:* dime@ietf.org
> *Subject:* RE: [Dime] RFC 3588 - fixed positioned session-ID AVPs
>
>
>
> David Lehmann [mailto://dlehmann@ulticom.com] <[mailto://dlehmann@ulticom.com%5d> 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
>
>
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