Cisco Cisco IOS Software Release 15.0(1)SY

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

If MDS is enabled on the incoming interface, but at least one of the outgoing interfaces cannot fast switch, packets are process
switched.

We recommended that you disable fast switching on any interface when MDS is enabled.

Note

How to Configure Multicast Distributed Switching

Configuring Multicast Distributed Switching

Perform the following task to configure MDS. To configure MDS, you must enable it globally and on at least one interface because
MDS is an attribute of the interface.

When you enable an interface to perform distributed switching of incoming multicast packets, you are
configuring the physical interface, not the logical interface (subinterface). All subinterfaces are included
in the physical interface.

Note

Procedure

Purpose

Command or Action

Enables privileged EXEC mode.

enable

Step 1

Example:

Router> enable

• Enter your password if prompted.

Enters global configuration mode.

configure terminal

Example:

Router# configure termi

Step 2

n
al

Enables IP multicast routing.

ip multicast-routing distributed

Step 3

Example:

Router(config)# ip multicast-routing
distributed

• The distributed keyword enables MDS globally.