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Chapter 48 Configuring IP Multicast Routing
Configuring IP Multicast Routing
Use these privileged EXEC commands to display information about PIM stub configuration and status:
show ip pim interface displays the PIM stub that is enabled on each interface.
show ip igmp detail displays the interested clients that have joined the specific multicast source
group.
show ip igmp mroute verifies that the multicast stream forwards from the source to the interested
clients.
Configuring a Rendezvous Point
You must have an RP if the interface is in sparse-dense mode and if you want to treat the group as a sparse
group. You can use several methods, as described in these sections:
Manually Assigning an RP to Multicast Groups, page 48-24
Configuring Auto-RP, page 48-26 (a standalone, Cisco-proprietary protocol separate from PIMv1)
Configuring PIMv2 BSR, page 48-30 (a standards track protocol in the Internet Engineering Task
Force [IETF])
You can use auto-RP, BSR, or a combination of both, depending on the PIM version that you are running
and the types of routers in your network. For more information, see the “PIMv1 and PIMv2
Interoperability” section on page 48-11 and the “Auto-RP and BSR Configuration Guidelines” section
on page 48-12.

Manually Assigning an RP to Multicast Groups

This section explains how to manually configure an RP. If the RP for a group is learned through a
dynamic mechanism (such as auto-RP or BSR), you need not perform this task for that RP.
Senders of multicast traffic announce their existence through register messages received from the source
first-hop router (designated router) and forwarded to the RP. Receivers of multicast packets use RPs to
join a multicast group by using explicit join messages. RPs are not members of the multicast group;
rather, they serve as a meeting place for multicast sources and group members.
You can configure a single RP for multiple groups defined by an access list. If there is no RP configured
for a group, the multilayer switch treats the group as dense and uses the dense-mode PIM techniques.