HP MSR2000/3000/4000 Router Series IP Multicast Configuration Guide

15
Basic IGMP snooping concepts
IGMP snooping related ports
As shown in Figure 12, IGMP snooping runs on Switch A and Switch B, and Host A and Host C are
receivers in a multicast group.
Figure 12 IGMP snooping related ports
The following describes the ports involved in IGMP snooping:
• Router port—Layer 3 multicast device-side port. Layer 3 multicast devices include designated
routers (DRs) and IGMP queriers. In Figure 12, Ether
net 1/1 of Switch A and Ethernet 1/1 of Switch
B are the router ports. A switch records all its router ports in a router port list.
Do not confuse the "router port" in IGMP snooping with the "routed interface" commonly known as
the "Layer 3 interface." The router port in IGMP snooping is a Layer 2 interface.
• Member port—Multicast receiver-side port. In Figure 12, Ether
net 1/2 and Ethernet 1/3 of Switch
A and Ethernet 1/2 of Switch B are the member ports. A switch records all its member ports in the
IGMP snooping forwarding table.
Unless otherwise specified, router ports and member ports in this document include both static and
dynamic router ports and member ports.
NOTE:
W
hen IGMP snooping is enabled, all ports that receive PIM hello messages or IGMP
g
eneral queries with
the source addresses other than 0.0.0.0 are considered dynamic router ports. For more information abou
t
PIM hello messages, see "Configuring PIM."