Cisco Systems 78-11741-02 manual Including a Bordering PIM Dense Mode Region in Msdp, IPC-486

Configuring Multicast Source Discovery Protocol

MSDP Configuration Task List

Including a Bordering PIM Dense Mode Region in MSDP

You might have a router that borders a PIM-SM region with a dense mode region. By default, sources in the dense mode region are not included in MSDP. You could configure this border router to send SA messages for sources active in the dense mode region. If you do so, it is very important to also configure the ip msdp redistribute global configuration command to apply to only local sources. Not configuring this command can result in (S, G) state remaining long after a source in the dense mode domain has stopped sending.

To configure the border router to send SA messages for sources active in the dense mode region, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip msdp border sa-address type	Configures the router on the border between a dense mode and
number	sparse mode region to send SA messages about active sources
	in the dense mode region. The IP address of the interface is used
	as the originator ID, which is the RP field in the SA message.

Note The ip msdp border command is not recommended. It is better to configure the border router in the sparse mode domain to proxy-register sources in the dense mode domain to the RP of the sparse mode domain and have the sparse mode domain use standard MSDP procedures to advertise these sources.

Configuring an Originating Address Other Than the RP Address

If you want to change the originator ID for any reason, use the ip msdp originator-idglobal configuration command in this section. For example, you might change the originator ID in one of these cases:

•If you configure a logical RP on multiple routers in an MSDP mesh group. For an example of a logical RP, see the section “Logical RP” later in this document.

•If you have a router that borders a PIM sparse mode domain and a dense mode domain. If a router borders a dense mode domain for a site, and sparse mode is being used externally, you might want dense mode sources to be known to the outside world. Because this router is not an RP, it would not have an RP address to use in an SA message. Therefore, this command provides the RP address by specifying the address of the interface.

To allow an MSDP speaker that originates an SA message to use the IP address of its interface as the RP address in the SA message, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip msdp originator-id type number	Configures the RP address in SA messages to be the address of
	the originating router’s interface.

Cisco IOS IP Configuration Guide

IPC-486