Information Transmission In The Broadcast Mode; Information Transmission In The Multicast Mode - H3C S7500 Series Operation Manual

Operation Manual – Multicast
H3C S7500 Series Ethernet Switches
information, when a large number of users need this information, the server must send
many pieces of information with the same content to the users. Therefore, the limited
bandwidth becomes the bottleneck in information transmission. This shows that unicast
is not good for the transmission of a great deal of information.

1.1.2 Information Transmission in the Broadcast Mode

When you adopt broadcast, the system transmits information to all users on a network.
Any user on the network can receive the information, no matter the information is
needed or not.
Source
Server
Figure 1-2 Information transmission in the broadcast mode
Assume that users B, D, and E need the information. The source server broadcasts this
information through routers, and users A and C on the network also receive this
information. The security and payment of the information cannot be guaranteed.
As we can see from the information transmission process, the security and legal use of
paid service cannot be guaranteed. In addition, when only a small number of users on
the same network need the information, the utilization ratio of the network resources is
very low and the bandwidth resources are greatly wasted.
Therefore, broadcast is disadvantageous in transmitting data to specified users;
moreover, broadcast occupies large bandwidth.

1.1.3 Information Transmission in the Multicast Mode

As described in the previous sections, unicast is suitable for networks with sparsely
distributed users, whereas broadcast is suitable for networks with densely distributed
Figure 1-2 shows information transmission in broadcast mode.
Packets for all the network
Host A
Receiver
Receiver
R eceiver
Host E
1-2
Chapter 1 Multicast Overview
Host B
Host C
Host D