Manually Assigning An Rp To Multicast Groups - Cisco Catalyst 3750 Software Configuration Manual

Configuring IP Multicast Routing

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's 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.
Beginning in privileged EXEC mode, follow these steps to manually configure the address of the RP.
This procedure is optional.
Command
Step 1 configure terminal
Step 2
ip pim rp-address ip-address
[access-list-number] [override]
Step 3 access-list access-list-number {deny |
permit} source [source-wildcard]
Step 4
end
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Purpose
Enter global configuration mode.
Configure the address of a PIM RP.
By default, no PIM RP address is configured. You must configure the IP
address of RPs on all routers and multilayer switches (including the RP).
If there is no RP configured for a group, the switch treats the group as
dense, using the dense-mode PIM techniques.
A PIM device can be an RP for more than one group. Only one RP address
can be used at a time within a PIM domain. The access-list conditions
specify for which groups the device is an RP.
For ip-address, enter the unicast address of the RP in dotted-decimal
•
notation.
(Optional) For access-list-number, enter an IP standard access list
•
number from 1 to 99. If no access list is configured, the RP is used for
all groups.
(Optional) The override keyword means that if there is a conflict
•
between the RP configured with this command and one learned by
Auto-RP or BSR, the RP configured with this command prevails.
Create a standard access list, repeating the command as many times as
necessary.
For access-list-number, enter the access list number specified in
•
Step 2.
The deny keyword denies access if the conditions are matched. The
•
permit keyword permits access if the conditions are matched.
For source, enter the multicast group address for which the RP should
•
be used.
(Optional) For source-wildcard, enter the wildcard bits in dotted
•
decimal notation to be applied to the source. Place ones in the bit
positions that you want to ignore.
Recall that the access list is always terminated by an implicit deny
statement for everything.
Return to privileged EXEC mode.
Chapter 31 Configuring IP Multicast Routing
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