Prerequisites For Igmp Snooping; Restrictions For Igmp And Igmp Snooping; Restrictions For Configuring Igmp - Cisco Catalyst 3850 series Configuration Manual

Prerequisites for IGMP Snooping

• The tasks in this module assume that IP multicast has been enabled and that the Protocol Independent
Prerequisites for IGMP Snooping
Observe these guidelines when configuring the IGMP snooping querier:
• Configure the VLAN in global configuration mode.
• Configure an IP address on the VLAN interface. When enabled, the IGMP snooping querier uses the IP
• If there is no IP address configured on the VLAN interface, the IGMP snooping querier tries to use the
• The IGMP snooping querier supports IGMP Versions 1 and 2.
• When administratively enabled, the IGMP snooping querier moves to the nonquerier state if it detects
• When it is administratively enabled, the IGMP snooping querier moves to the operationally disabled

Restrictions for IGMP and IGMP Snooping

Restrictions for Configuring IGMP

The following are the restrictions for configuring IGMP:
• The device supports IGMP Versions 1, 2 , and 3.
• IGMP Version 3 uses new membership report messages that might not be correctly recognized by older
• IGMPv3 can operate with both ISM and SSM. In ISM, both exclude and include mode reports are
IP Multicast Routing Configuration Guide, Cisco IOS XE Release 3.6E (Catalyst 3850 Switches)
32
Multicast (PIM) interfaces have been configured using the tasks described in the "Configuring Basic IP
Multicast Routing" module.
address as the query source address.
configured global IP address for the IGMP querier. If there is no global IP address specified, the IGMP
querier tries to use the VLAN device virtual interface (SVI) IP address (if one exists). If there is no SVI
IP address, the device uses the first available IP address configured on the device. The first IP address
available appears in the output of the show ip interface privileged EXEC command. The IGMP snooping
querier does not generate an IGMP general query if it cannot find an available IP address on the device.
the presence of a multicast router in the network.
state under these conditions:
◦ IGMP snooping is disabled in the VLAN.
◦ PIM is enabled on the SVI of the corresponding VLAN.
For IGMP Version 3, only IGMP Version 3 BISS (Basic IGMPv3 Snooping Support)
Note
is supported.
IGMP snooping devices.
applicable. In SSM, only include mode reports are accepted by the last-hop router. Exclude mode reports
are ignored.
Configuring IGMP
OL-32598-01