Subject: N-1-4-030.60.2 TECHNOLOGY AND TRENDS: IETF Audio & Videocast Ron Frederick, Xerox PARC Digital audio and video on the desktop is starting to become quite commonplace. Most modern workstations, and many PCs, come equipped with digital audio hardware of some sort, and video capture support is often available for a fairly low cost. Modern processors are finally fast enough to make processing of this audio and video data feasible without expensive coprocessor support, at least for simple tasks. This has led to an interesting new type of traffic on the Internet. In March of 1992, at the Internet Engineering Task Force (IETF) meeting in San Diego, there was a technology demonstration of digital audio on the Internet. The IETF general sessions and several of the working group sessions were "audiocast" out to about 20 remote sites, using IP multicast packet delivery of sampled audio on a SPARCstation. Remote listeners were spread all around the world. They could also talk back to the local IETF audience, and were able to participate in some of the working group sessions. The audio quality wasn't perfect, but overall it worked quite well, and was considered a great success. Since March, two other IETF meetings have been held, and this transmission of multimedia data across the Internet has continued to grow. At the last meeting in November, over 200 Internet networks in 15 countries were able to receive the broadcast, which at one point in the week included two simultaneous video and audio streams. To accomplish this, a mesh of routers were set up to provide multicast forwarding, and this has been named the "MBONE", or multicast backbone. This infrastructure has remained in place even after the IETF meeting and it was used to broadcast other meetings, such as the Australian Networkshop and the MCNC-CONCERT Packet Video Workshop in early December 1992. The IETF continues to pursue several issues related to this technology. In particular, there is a working group which is standardizing multicast extension s to the OSPF routing protocol, a working group developing a transport protocol suitable for real-time traffic such as audio and video, and a BOF which meets to talk about remote conferencing. Those interested in keeping up to date on this work, as well as future Internet audio and videocasts, should subscribe to the remote conferencing mailing list. To get more information, send a message to "rem-conf-request@es.net".