Multicast Architecture; Multicast Address - H3C S7500 Series Operation Manual

Operation Manual – Multicast
H3C S7500 Series Ethernet Switches
Multicast provides the following applications:
Applications of multimedia and flow media, such as Web TV, Web radio, and
real-time video/audio conferencing.
Communication for training and cooperative operations, such as remote
education.
Database and financial applications (stock), and so on.
Any point-to-multiple-point data application.

1.2 Multicast Architecture

IP multicast is designed to transmit information from a multicast source to receivers in
the multicast mode and to satisfy information requirements of receivers. You should be
concerned about:
Host registration: What receivers reside on the network?
Multicast source discovery: Which multicast source should the receivers receive
information from?
Multicast addressing mechanism: Where should the multicast source transmit
information to?
Multicast routing: How is information transmitted?
IP multicast is a kind of peer-to-peer service. Based on the protocol layer sequence
from bottom to top, the multicast mechanism contains addressing mechanism, host
registration, multicast routing, and multicast application.
Addressing mechanism: Information is sent from a multicast source to a group of
receivers through multicast addresses.
Host registration: A receiving host joins and leaves a multicast group dynamically
to implement multicast membership registration.
Multicast routing: A router or switch establishes a packet distribution tree and
transmits packets from a multicast source to receivers.
Multicast application: A multicast source must support multicast applications, such
as video conferencing. The TCP/IP protocol stack must support the function of
sending and receiving multicast information.

1.2.1 Multicast Address

As receivers are multiple hosts in a multicast group, you should be concerned about the
following questions:
What destination should the information source send the information to in the
multicast mode?
How to select the destination address, that is, how does the information source
know who the user is?
These questions are about multicast addressing. To enable the communication
between the information source and members of a multicast group (a group of
1-5
Chapter 1 Multicast Overview