Command:

ip mroute-cache


Mode:

Router(config-if)#

Syntax:

ip mroute source-address mask [protocol as-number] {rpf-address | type number} [distance]

no ip mroute source-address mask [protocol as-number] {rpf-address | type number} [distance]


Syntax Description:
source-address IP address of the multicast source.
mask Mask on the IP address of the multicast source.
protocol (Optional) Unicast routing protocol that you are using.
as-number (Optional) Autonomous system number of the routing protocol you are using, if applicable.
rpf-address Incoming interface for the mroute. If the Reverse Path Forwarding (RPF) address rpf-address is a Protocol Independent Multicast (PIM) neighbor, PIM join, graft, and prune messages are sent to it. The rpf-address argument can be a host IP address of a directly connected system or a network/subnet number. When it is a route, a recursive lookup is done from the unicast routing table to find a directly connected system. If the rpf-address argument is not specified, the interface type number value is used as the incoming interface.
type-number Interface type and number for the mroute.
distance (Optional) Determines whether a unicast route, a Distance Vector Multicast Routing Protocol (DVMRP) route, or a static mroute should be used for the RPF lookup. The lower distances have better preference. If the static mroute has the same distance as the other two RPF sources, the static mroute will take precedence. The default is 0.

Command Description:

To configure IP multicast fast switching or multicast distributed switching (MDS), use the ip mroute-cache interface configuration command. To disable either of these features, use the no form of this command.

Usage Guidelines

On the RSP

If multicast fast switching is disabled on an incoming interface for a multicast routing table entry, the packet will be sent at process level for all interfaces in the outgoing interface list.

If multicast fast switching is disabled on an outgoing interface for a multicast routing table entry, the packet is process level switched for that interface, but may be fast-switched for other interfaces in the outgoing interface list.

When multicast fast switching is enabled (like unicast routing), debug messages are not logged. If you want to log debug messages, disable fast switching.

If MDS is not enabled on an incoming interface that is capable of MDS, incoming multicast packets will not be distributed switched; they will be fast-switched at the RP as before. Also, if the incoming interface is not capable of MDS, packets will get fast-switched or process-switched at the RP as before.

If MDS is enabled on the incoming interface, but at least one of the outgoing interfaces cannot fast-switch, packets will be process-switched. So it is a good idea not to disable fast switching on any interface when MDS is enabled.

On the GSR

On the GSR, all interfaces should be configured for MDS because that is the only switching mode.


Example:

The following example enables IP multicast fast switching on the interface:

Router(config-if)#no ip mroute-cache


The following example disables IP multicast fast switching on the interface:
Router(config-if)#no ip mroute-cache


The following example enables MDS on the interface:
Router(config-if)#ip mroute-cache distributed


The following example disables MDS and IP multicast fast switching on the interface:
Router(config-if)#no ip mroute-cache distributed

Misconceptions:
None

Related Commands:
ip multicast-routing

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