Hi,

The SDP RFC allows a FQDN, but the sdp-new draft
(draft-ietf-mmusic-sdp-new-03.txt) only allows an IP address. I don't
think that SIP defines any rule for this separately.

Regards,

Christer Holmberg
Ericsson Finland


Bob Penfield wrote:
> 
> Hi Tim,
> 
> Although the SDP RFC allows a FQDN in the c-line, for SIP I believe that
> only IP addresses should be used. I'm not sure if that is called out in bis
> or some other draft.
> 
> If some of the media streams are acceptable, you could just disable the
> unacceptable ones by setting the port number to 0 in accordance with
> http://www.ietf.org/internet-drafts/draft-rosenberg-mmusic-sdp-offer-answer-
> 00.txt
> Otherwise you should reject the request with a 488 (Unacceptable Here)
> response.
> 
> If there are no acceptable streams, a 488 should be returned.
> 
> If the offer is in a 200-OK, you need to send the ACK. But then you would
> need to re-INVITE or send a BYE immediately. If you're going to send BYE,
> you probably want to set all the port numbers to 0 in the answer SDP in the
> ACK so that the far end does not start sending media.
> 
> cheers,
> (-:bob
> 
> Robert F. Penfield
> Chief Software Architect
> Acme Packet, Inc.
> 130 New Boston Street
> Woburn, MA 01801
> [EMAIL PROTECTED]
> 
> ----- Original Message -----
> From: "Tim Johnson" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, November 08, 2001 9:45 PM
> Subject: [Sip-implementors] SDP with unresolved connection address
> 
> > I have a question about what, if any, SIP behaviour there should be
> > if a UA receives SDP with a connection address expressed as a
> > domain name and which cannot be resolved. In this case at least one,
> > and possibly all, media streams cannot be sent. This is also similar
> > to an ARP failure on a LAN but probably much more likely to occur.
> > There is also a similarity to receiving an ICMP unreachable
> > indication for a media stream in progress. In all cases the media
> > cannot be sent yet the signalling channel, especially in the case of
> > 3PCC, may be unaffected.
> >
> > If the SDP was in an INVITE, the response could indicate a DNS
> > resolution failure (although no response codes are defined which
> > cover this specific case). But the SDP could also be in either a 2xx
> > response or in an ACK. In these cases, a re-INVITE could be sent
> > following the completion of the INVITE transaction which
> > contained the unresolved name. Alternatively, a BYE could be sent
> > to terminate the session. Finally, the session could be unaffected and
> > corrective actions left to the user which notices a lack of media.
> >
> > Only the BYE seems deterministic since a response to a re-INVITE
> > is likely to contain the same SDP as caused the resolution failure.
> > However it would appear to be too drastic if there were other media
> > streams in the session which did resolve (i.e. the c= which did not
> > resolve was within one of several media descriptions and not at the
> > session level). What is the accepted solution here?
> >
> > Thanks,
> > Tim
> >
> > _______________________________________________
> > Sip-implementors mailing list
> > [EMAIL PROTECTED]
> > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
> >
> 
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