IP Multicast Support
IP Multicast Support |
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In a configuration very similar to the single router intranet connected to the MBone, a Windows 2000–based router can provide multicast capabilities as a peripheral router connected to a multicast-enabled private intranet. A peripheral router is a router attached to multiple subnets; however, only a single attached subnet contains another router. In this case, the other router is a multicast core router, a multicast router running routing protocols that is part of the multicast-enabled intranet.
In this configuration, all interfaces are added to the IGMP routing protocol. All interfaces not containing the multicast router are configured for IGMP router mode and the interface connected to the subnet containing the multicast core router is configured for IGMP proxy mode.
Hosts joining multicast groups send IGMP Host Membership Reports, which are copied on the interface attached to the subnet containing the multicast core router. Multicast traffic from the intranet is forwarded to the IGMP proxy mode interface subnet. When received, the multicast traffic is forwarded to the host on the appropriate subnet. Multicast traffic sent by a host on an attached subnet is copied to the IGMP proxy mode interface subnet. The multicast core router either ignores the multicast traffic or forwards it to downstream host group members.
The peripheral router in a multicast-enabled intranet configuration is shown in Figure 4.8.
Figure 4.8 Peripheral Router in a Multicast-Enabled Intranet
