IP Multicast

What is IP Multicast?

IP multicast is the delivery of data on a one-to-many or many-to-many format. It is also known as source based delivery since the addresses of those who wish to receive the data traffic may not be known. The receivers must express interest (join the multicast group) in order to receive the traffic from that group. The traffic could be audio, video, or data. Think radio, TV, or stock prices.

Harvard currently has Multicast enabled on the Core Network, and the LMAnet (Longwood Medical Area Network). Harvard has MBGP(Multi-protocol Border Gateway Protocol) and MSDP (Multicast Source Discovery Protocol) peering sessions established with the Northern Crossroads gigaPOP and The Northern Crossroads currently provides MBGP/MSDP peering to its members and maintains multicast peering with the Internet2 backbone network Abilene.

Multicast provides greater efficiency of network resources, allowing one stream of video data to be watched by hundred’s or thousand’s of user’s. Unicast video streaming requires a separate stream for each end user that wishes to view the stream.

Harvard groups within the Medical Area have used Multicast to stream lectures and surgeries to other universities. The success of these lectures has lead to the scheduling of additional lectures to be broadcast.

Multicast Engineering FAQ (NLANR, National Laboratory for Advanced Network Research)

http://www.ncne.nlanr.net/documentation/faq/mcast_eng_faq.html

Internet2 Multicast Resources

Internet2 Multicast Working Group Resources

For Additional Information:

Leo Donnelly