Cisco ASA 5505 Configuration Manual page 459

Chapter 24 Configuring Multicast Routing
Click OK.
Step 4
Modifying the Query Messages to Multicast Groups
The adaptive security appliance 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 adaptive
security appliance. If the adaptive security appliance 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 adaptive security appliance 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:
In the main ASDM window, choose Configuration > Device Setup > Routing > Multicast > IGMP >
Step 1
Protocol.
Choose the interface you want to limit from the table on the Protocol pane, and click Edit.
Step 2
The Configure IGMP Parameters dialog box appears.
In the Query Interval field, enter the interval, in seconds, at which the designated router sends IGMP
Step 3
host-query messages. Valid values range from 1 to 3600 seconds. The default value is 125 seconds.
If the adaptive security appliance does not hear a query message on an interface for the specified
timeout value, then the adaptive security appliance becomes the designated router and starts sending
the query messages.
In the Query Timeout field, enter the period of time, in seconds, before which the adaptive security
Step 4
appliance takes over as the requester for the interface after the previous requester has stopped doing so.
Valid values range from 60 to 300 seconds. The default value is 255 seconds.
Click OK.
Step 5
Changing the IGMP Version
By default, the adaptive security appliance runs IGMP Version 2, which enables several additional
features.
All multicast routers on a subnet must support the same version of IGMP. The adaptive security
appliance 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 adaptive security appliance running IGMP Version
2 works correctly when IGMP Version 1 hosts are present.
To control which version of IGMP is running on an interface,perform the following steps:
OL-20339-01
Cisco ASA 5500 Series Configuration Guide using ASDM
Customizing Multicast Routing
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