3Com Switch 8800 Advanced Software V5 Configuration Guide

Displaying and Maintaining IGMP Snooping 555
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CAUTION: Be sure to configure the maximum number of multicast groups
allowed on a port to be in the range of 1 to 511 before configuring multicast
group replacement. Otherwise, the multicast group replacement functionality will
not take effect.
Displaying and
Maintaining IGMP
Snooping
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■ The reset igmp-snooping group command works only on an IGMP
Snooping-enabled VLAN, but not on a VLAN with IGMP enabled on its VLAN
interface.
■ The reset igmp-snooping group command cannot clear IGMP Snooping
entries of static joins.
IGMP Snooping
Configuration
Examples
Configuring Simulated
Joining
Network requirements
■ As shown in Figure 171, Router A connects to the multicast source through
Ethernet1/1/2 and to Switch A (Switch 8800) through Ethernet1/1/1. Router A
is the IGMP querier on the subnet.
■ IGMPv3 runs on Router A and Switch A. IGMPv3 Snooping runs on Switch A.
PIM-SM runs on Router A. Ethernet1/1/2 is to be configured as C-BSR and
C-RP.
■ Perform the following configuration so that multicast data (1.1.1.1, 224.1.1.1)
can be forwarded through Ethernet1/1/2 and Ethernet1/1/3 even if Host A and
Host B temporarily stop receiving multicast data for some unexpected reasons.
To do...
Use the command...
View the information of multicast groups
learned by IGMP Snooping
display igmp-snooping group [ vlan vlan-id
] [ slot slot-id ] [ verbose ]
View the statistics information of IGMP
messages learned by IGMP Snooping
display igmp-snooping statistics
Clear IGMP Snooping entries reset igmp-snooping group { group-address
| all } [ vlan vlan-id ]
Clear the statistics information of all kinds of
IGMP messages learned by IGMP Snooping
reset igmp-snooping statistics