CCIE RS – L3 Multicast – Implement and Troubleshoot MSDP

Implement and Troubleshoot Multicast Source Discovery Protocol (MSDP)

  • Connect multiple PIM-SM domains together
  • Allows load balancing of RP’s
  • RP’s exchange information about active sources
  • Runs over TCP
    • Uses underlying routing protocol
  • Peering relationship


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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.


Intra-domain MSDP (Anycast RP)

Provide RP redundancy and load-balancing

  • Load balancing achieved through MSDP
 ip pim sparse-dense-mode

ip pim rp-address rp-address access-list

ip pim send-rp-announce

ip pim send-rp-discovery

ip msdp peer {peer-address peer-nameconnect-source type number

ip msdp mesh-group mesh-name {peer-address | peer-name

ip msdp originator-id type number


SA Filtern (Source Active)

By default, only routers that are caching SA information can respond to SA request messages. By default, such a router honors all SA request messages from its MSDP peers. That is, it will supply the IP addresses of the sources that are active.

However, you can configure the router to ignore all SA request messages from an MSDP peer. Or, you can honor only those SA request messages from a peer for groups described by a standard access list. If the access list passes, SA request messages will be accepted. All other such messages from the peer for other groups will be ignored.


Router(config)# ip msdp filter-sa-request {peer-address | peer-name}

Filters all SA request messages from the specified MSDP peer.

Router(config)# ip msdp filter-sa-request {peer-address | peer-name}list access-list 

Filters SA request messages from the specified MSDP peer for groups that pass the standard access list. The access list describes a multicast group address


MSDP filter allows for

  • Filter all source/group pairs
  • Specify an extended access list to pass only certain source/group pairs
  • Filter based on match criteria in a route map


Router(config)# ip msdp sa-filter out {peer-address | peer-name}

Filters all SA messages to the specified MSDP peer

Router(config)# ip msdp sa-filter out {peer--address | peer-name} list access-list 

To the specified MSDP peer, passes only those SA messages that pass the extended access list.

Router(config)# ip msdp sa-filter out {peer-address | peer-name} route-map map-name 

To the specified MSDP peer, passes only those SA messages that meet the match criteria in the route map map-tag value.

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