Subject: Help with Listening for Session Announcements...

From: Chris van der Merwe <[email-masked]>
Date: Mon, 16 Aug 1999 15:16:40 +0200

Hi Guys;

I'm wondering if anyone can't point me in the right direction. I'm looking 
to find out the mechanism that sdr uses to listen for current Mbone 
sessions advertised by the local mrouted (or other router on the subnet 
advertising sessions).

I've tried uses Microsoft's Network Monitor - I noticed a few connections 
being made to:
224.2.127.254 (SAP.MCAST.NET)
224.0.1.75 (SIP.MCAST.ENT)

These connections used the IGMP protocol. Which as far as I know is only 
used to join multicast groups.

But I had no luck in trapping a message with a filter set to (as an 
example) the name of a current session. The filter not working could be 
another Microsoft feature but I don't have access to another monitor. 
Perhaps someone could direct me to the relevant page in rfc 2327 (for sdp) 
or rfc 2326 (for sap). I had a brief look at these but couldn't find the 
relevant

Thanks any help would be appreciated, I'm trying to avoid digging through 
the source code of sdr to find out.

Regards
  Chris

---

From: Colin Perkins <[email-masked]>
Date: Mon, 16 Aug 1999 16:01:56 +0100

[This question is better suited to the MMUSIC working group's mailing list,
[email-masked]]

>sessions advertised by the local mrouted (or other router on the subnet 

Mrouted handles multicast routing, it's not involved in sdr session
announcement.

>used to join multicast groups.

Correct.

>or rfc 2326 (for sap). I had a brief look at these but couldn't find the 

See http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sap-v2-01.txt for
the current draft of the SAP protocol, which is used by SDR to announce
sessions. 

Colin