26-4
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter26 Configuring Multicast Routing
Customizing Multicast Routing
Customizing Multicast Routing
This section describes how to customize multicast routing and includes the following topics:
Configuring Stub Multicast Routing and Forwarding IGMP Messages, page26-4
Configuring a Static Multicast Route, page26-4
Configuring IGMP Features, page26-5
Configuring PIM Features, page26-9
Configuring a Bidirectional Neighbor Filter, page26-13
Configuring a Multicast Boundary, page26-14

Configuring Stub Multicast Routing and Forwarding IGMP Messages

Note Stub multicast routing and PIM are not supported concurrently.
An ASA acting as the gateway to the stub area does not need to participate in PIM. Instead, you can
configure it to act as an IGMP proxy agent and forward IGMP messages from hosts connected on one
interface to an upstream multicast router on another interface. To configure the ASA as an IGMP proxy
agent, forward the host join and leave messages from the stub area interface to an upstream interface.
To forward the host join and leave messages, enter the following command from the interface attached
to the stub area:

Configuring a Static Multicast Route

Configuring static multicast routes lets you separate multicast traffic from unicast traffic. For example,
when a path between a source and destination does not support multicast routing, the solution is to
configure two multicast devices with a GRE tunnel between them and to send the multicast packets over
the tunnel.
When using PIM, the ASA expects to receive packets on the same interface where it sends unicast
packets back to the source. In some cases, such as bypassing a route that does not support multicast
routing, you may want unicast packets to take one path and multicast packets to take another.
Static multicast routes are not advertised or redistributed.
To configure a static multicast route or a static multicast route for a stub area, enter one of the following
commands:
Command Purpose
igmp forward interface if_name
Example:
hostname(config-if)# igmp forward
interface interface1
Configures stub multicast routing and forwards IGMP messages.