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Configuring Multicast Source Discovery Protocol
MSDP Configuration Task List
IPC-480
Cisco IOS IP Configuration Guide
Configuring an MSDP Peer
You enable MSDP by configuring an MSDP peer to the local router.
Note The router you specify by Domain Naming System (DNS) name or IP address as an MSDP peer is
probably a Border Gateway Protocol (BGP) neighbor. If it is not, see the section “Configuring a
Default MSDP Peer” later in this document.
To configure an MSDP peer, use the following commands in global configuration mode as needed. The
second command is optional.
Caching SA State
By default, the router does not cache source/group pairs from received SA messages. Once the router
forwards the MSDP SA information, it does not store it in memory. Therefore, if a member joins a group
soon after an SA message is received by the local RP, that member will need to wait until the next SA
message to hear about the source. This delay is known as join latency.
If you want to sacrifice some memory in exchange for reducing the latency of the source information,
you can configure the router to cache SA messages. To have the router cache source/group pairs, use the
following command in global configuration mode:
An alternative to caching the SA state is to request source information from a peer, which is described
in the following section, “Requesting Source Information from an MSDP Peer.” If you cache the
information, you need not trigger a request for it.
Command Purpose
Router(config)# ip msdp peer {peer-name |
peer-address} [connect-source type number]
[remote-as as-number]
Enables MSDP and configures an MSDP peer as specified by
the DNS name or IP address.
If you specify the connect-source keyword, the primary
address of the specified local interface type and number values
are used as the source IP address for the TCP connection. The
connect-source keyword is recommended, especially for
MSDP peers on a border that peer with a router inside the
remote domain.
Router(config)# ip msdp description {peer-name |
peer-address} text
Configures a description for a specified peer to make it easier
to identify in a configuration or in show command output.
Command Purpose
Router(config)# ip msdp cache-sa-state [list
access-list]
Creates SA state (cache source/group pairs). Those pairs that
pass the access list are cached.