Lectures notes for 2010 - KTH

Broadcast and Multicast
Traditionally the Internet was designed for unicast communication (one sender
and one receiver) communication.
Increasing use of multimedia (video and audio) on the Internet
• One-to-many and many-to-many communication is increasing
• In order to support these in a scalable fashion we use multicasting.
• Replicating UDP packets where paths diverge (i.e., split)
MBONE was an experimental multicast network which operated for a number of
years. (see for example http://www-mice.cs.ucl.ac.uk/multimedia/software/ and
http://www.ripe.net/ripe/wg/mbone/home.html )
Multicasting is useful for:
• Delivery to multiple recipients
• reduces traffic, otherwise each would have to be sent its own copy (“internet radio/TV”)
• Solicitation of service (service/server discovery)
• Not doing a broadcast saves interrupting many clients
Maguire Broadcast and Multicast 8: 4 of 78
maguire@kth.se 2010.03.21 Internetworking/Internetteknik