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I2 Institutions Invited to Join SSM Beta Testing Project
Lucy Lynch
llynch@darkwing.uoregon.edu
An extension to IP (Internet Protocol) multicast called "Source Specific Multicast," or SSM, is now available for testing by Internet2 institutions with an interest in multicast or real-time video broadcasting over the Internet.
The new technology made its debut during the August 2000 Internet2 Joint Techs meeting in Toronto, where the first end-to-end SSM session was sourced across the Internet2/Abilene network backbone. The test session was the result of a collaborative effort by Greg Shepherd of Cisco Systems and the UO, Mark Fullmer (Ohio State University), Matt Davy (Indiana University) and UO Computing Center support specialist Hans Kuhn. It was repeated in the fall for the 37th RIPE (Rˇseaux IP Europˇens) meeting in Amsterdam, with a live presentation by Arjen Boers of Cisco Systems as part of the Multicast Routing Workshop (see http://www.ripe.net/ripe/meetings/current/ripe-37/#multicast).
SSM requires the host to learn about a specific source independently of the Multicast Routing Protocol used in the network. This is usually accomplished by posting the source/group information on a web page consisting of cgi script that starts a particular multicast application on the receiving host.
IGMPv3 is the standard protocol for setting up an SSM data path, but IGMPv3-lite and URD (URL Rendezvous Directory) are viable alternatives. Both IGMPv3-lite and URD enable a user to easily join a multicast group and receive content transmitted to that group, while providing the network administrator with enhanced capabilities to manage multicast streams. (Note that IGMPv3 requires modification of both the host operating system and the multicast application, whereas URD and IGMPv3-lite do not.)
Internet2 institutions interested in multicast or real-time video broad-casting are invited to join the SSM beta testing project. To participate, youÕll need to install the current SSM-capable image on at least one router on your campus (to obtain the current image for your router, contact Greg Shepherd at shep@cisco.com).
Questions about receiver solutions (URD, IGMP-aware Linux patches) and sourcing SSM broadcast content should be directed to multicast@lists.uoregon.edu
For more background information on SSM, see http://darkwing.uoregon.edu/~llynch/ssm-decoder.html