26-3
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter26 Configuring Multicast Routing
Guidelines and Limitations
Guidelines and Limitations
This section includes the guidelines and limitations for this feature.
Context Mode Guidelines
Supported in single context mode. In multiple context mode, unshared interfaces and shared interfaces
are not supported.
Firewall Mode Guidelines
Supported only in routed firewall mode. Transparent firewall mode is not supported.
IPv6 Guidelines
Does not support IPv6.
Enabling Multicast Routing
Enabling multicast routing lets you enable multicast routing on the ASA. Enabling multicast routing
enables IGMP and PIM on all interfaces by default. IGMP is used to learn whether members of a group
are present on directly attached subnets. Hosts join multicast groups by sending IGMP report messages.
PIM is used to maintain forwarding tables to forward multicast datagrams.
Note Only the UDP transport layer is supported for multicast routing.
To enable multicast routing, enter the following command:
Table26-1 lists the maximum number of entries for specific multicast tables based on the amount of
RAM on the ASA. Once these limits are reached, any new entries are discarded.
Command Purpose
multicast-routing
Example:
hostname(config)# multicast-routing
Enables multicast routing.
The number of entries in the multicast routing tables are limited by the
amount of RAM on the ASA.
Table26-1 Entry Limits for Multicast Tables
Table 16 MB 128 MB 128+ MB
MFIB 1000 3000 5000
IGMP
Groups
1000 3000 5000
PIM Routes 3000 7000 12000