Cisco 5505 - ASA Firewall Edition Bundle, Cli Configuration Manual

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Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring Multicast Routing
Customizing Multicast Routing
The ASA sends query messages to discover which multicast groups have members on the networks
attached to the interfaces. Members respond with IGMP report messages indicating that they want to
receive multicast packets for specific groups. Query messages are addressed to the all-systems multicast
group, which has an address of 224.0.0.1, with a time-to-live value of 1.
These messages are sent periodically to refresh the membership information stored on the ASA. If the
ASA discovers that there are no local members of a multicast group still attached to an interface, it stops
forwarding multicast packet for that group to the attached network, and it sends a prune message back
to the source of the packets.
By default, the PIM designated router on the subnet is responsible for sending the query messages. By
default, they are sent once every 125 seconds.
When changing the query response time, by default, the maximum query response time advertised in
IGMP queries is 10 seconds. If the ASA does not receive a response to a host query within this amount
of time, it deletes the group.
To change the query interval, query response time, and query timeout value, perform the following steps:
Detailed Steps
Changing the IGMP Version
By default, the ASA runs IGMP Version 2, which enables several additional features such as the igmp
query-timeout and igmp query-interval commands.
All multicast routers on a subnet must support the same version of IGMP. The ASA does not
automatically detect Version 1 routers and switch to Version 1. However, a mix of IGMP Version 1 and
2 hosts on the subnet works; the ASA running IGMP Version 2 works correctly when IGMP Version 1
hosts are present.
To control which version of IGMP is running on an interface, enter the following command:
Command Purpose
Step 1
igmp query-interval seconds
Example:
hostname(config-if)# igmp query-interval
30
Sets the query interval time in seconds.
Valid values range from 0 to 500; 125 is the default value.
If the ASA does not hear a query message on an interface for the
specified timeout value (by default, 255 seconds), then the ASA
becomes the designated router and starts sending the query
messages.
Step 2
igmp query-timeout seconds
Example:
hostname(config-if)# igmp query-timeout 30
Changes the timeout value of the query.
Valid values range from 0 to 500; 225 is the default
value.
Step 3
igmp query-max-response-time seconds
Example:
hostname(config-if)# igmp
query-max-response-time 30
Changes the maximum query response time.