Changing The Igmp Version; Modifying The Igmp Host-Query Message Interval - Cisco Catalyst 3120 Software Manual

Chapter 44 Configuring IP Multicast Routing
Command
Step 7 show ip igmp interface [interface-id]
Step 8
copy running-config startup-config
To disable groups on an interface, use the no ip igmp access-group interface configuration command.
This example shows how to configure hosts attached to a port as able to join only group 255.2.2.2:
Switch(config)# access-list 1 255.2.2.2 0.0.0.0
Switch(config-if)# interface gigabitethernet1/0/1
Switch(config-if)# ip igmp access-group 1

Changing the IGMP Version

By default, the switch uses IGMP Version 2, which provides features such as the IGMP query timeout
and the maximum query response time.
All systems on the subnet must support the same version. The switch does not automatically detect
Version 1 systems and switch to Version 1. You can mix Version 1 and Version 2 hosts on the subnet
because Version 2 routers or switches always work correctly with IGMPv1 hosts.
Configure the switch for Version 1 if your hosts do not support Version 2.
Beginning in privileged EXEC mode, follow these steps to change the IGMP version. This procedure is
optional.
Command
Step 1
configure terminal
Step 2 interface interface-id
Step 3 ip igmp version {1 | 2}
Step 4 end
Step 5
show ip igmp interface [interface-id]
Step 6
copy running-config startup-config
To return to the default setting, use the no ip igmp version interface configuration command.

Modifying the IGMP Host-Query Message Interval

The switch periodically sends IGMP host-query messages to discover which multicast groups are present
on attached networks. These messages are sent to the all-hosts multicast group (224.0.0.1) with a
time-to-live (TTL) of 1. The switch sends host-query messages to refresh its knowledge of memberships
present on the network. If, after some number of queries, the software discovers that no local hosts are
members of a multicast group, the software stops forwarding multicast packets to the local network from
remote origins for that group and sends a prune message upstream toward the source.
OL-12247-01
Purpose
Verify your entries.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Specify the interface to be configured, and enter interface
configuration mode.
Specify the IGMP version that the switch uses.
If you change to Version 1, you cannot configure the ip igmp
Note
query-interval or the ip igmp query-max-response-time
interface configuration commands.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
Configuring Optional IGMP Features
44-33