Subject: RE: [Fwd: [Fwd: [Sip] Few tiny issues with SDP section of bis3]]

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 21 Jun 2001 03:20:34 -0400

> -----Original Message-----
> From: Christian Huitema [mailto:[email-masked]]
> Sent: Thursday, June 14, 2001 11:17 AM
> To: Anders Kristensen
> Cc: Flemming Andreasen; [email-masked]; Jonathan Rosenberg
> Subject: RE: [Fwd: [Fwd: [Sip] Few tiny issues with SDP section of
> bis3]]
> 
> 
> Yes. In fact, we could make a session explaining that SDP was 
> originally
> defined for an entirely different purpose, that it is currently being
> revised, and that a bunch of fields defined in SDP shall be considered
> optional when used with SIP. I bet that this includes essentially all
> the fields that are not directly related to specifying 
> addresses, ports
> and coding parameters, plus the version field that we use in
> "re-invite."

Well, I'm trying to avoid the case where we have two separate SDP specs -
one for SAP, and one for SIP. Thus, I want the usage of SDP within SIP to be
completely compliant to the specification we have available, which is
rfc2327. I think we can agree that although the BNF doesn't require it, the
text is clear that rfc2327 mandates either e or p lines.

I AM willing, however, to mandate that people be willing to accept SDP
without these. Thus, the text would basically say that either e or p should
be present, as mandated by rfc2327, but because it serves little value in
sip, and is often ignored in practice, you MUST be prepared to process SDP
without it.

Maybe the difference is really academic, but I don't want to mandate that
people construct SDP in violation of the spec. I'd rather mandate that they
accept SDP that violates the spec.

-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

_______________________________________________
Sip mailing list
[email-masked]
http://www.ietf.org/mailman/listinfo/sip

---

From: Flemming Andreasen <[email-masked]>
Date: Fri, 22 Jun 2001 21:19:04 -0400

> text is clear that rfc2327 mandates either e or p lines.

That's not what Colin's reply indicated.

> accept SDP that violates the spec.

If the concern is simply to be SDP compliant, then why say anything about it (on
the sending side) ? Text duplication is the sure way to inconsistency so there
should rather just be a reference to RFC 2327. On the receiving side, I agree
it's a good idea to mandate lenient behavior.

-- Flemming

--
Flemming Andreasen
Cisco Systems

_______________________________________________
Sip mailing list  http://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: Colin Perkins <[email-masked]>
Date: Fri, 22 Jun 2001 22:14:20 -0400

>That's not what Colin's reply indicated.

That's what the current SDP spec mandates. Since it is widely ignored, and
we have an update of SDP in progress, we could make it optional in the new
revision.

>it's a good idea to mandate lenient behavior.

I think it would be better for SIP to be silent on the issue, and the
revision of SDP (for draft standard) to clarify one way or the other.

Colin