Chapter 38 IGMP
on a particular network. This in turn helps reduce the amount of multicast traffic going through the multicast router.
Figure 170 IGMP Version 2 Example
1 Query
2 Report |
| 3 Leave |
IGMP version 3 allows a multicast host to join a multicast group and specify from which source (multicast server) it wants to receive multicast packets. Alternatively, a multicast host can specify from which multicast servers it does not want to receive multicast packets. In the following figure multicast server X (IP address 10.1.1.1) and multicast server Z (IP address 13.2.2.2) both send multicast traffic to the same multicast group identified by the multicast IP address 225.1.1.1. In IGMP version 3 multicast host A can join multicast group
225.1.1.1and specify that it only wants to receive multicast packets from server
X.
Figure 171 IGMP Version 3 Example
XZ
Group: 225.1.1.1
Server: 10.1.1.1Group: 225.1.1.1
Server: 13.2.2.2
Join: 225.1.1.1
Include: 10.1.1.1
A
38.2 Port-based IGMP
The Switch sends IGMP Query packets to all ports. The Switch then listens for IGMP Report packets, and it records which port the messages came from. It then delivers multicast traffic to only those ports from which it received a request to join a multicast group.
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