ProLiant BL p-Class GbE Interconnect Switch Command Line Interface Reference Guide

Configuring the GbE Interconnect Switch using the Command Line Interface
Configuring IGMP Snooping
Internet Group Management Protocol (IGMP) snooping, when enabled and configured
properly, manages multicast traffic through a GbE Interconnect Switch. IP multicast traffic is
forwarded based on multicast group membership information registered by the GbE
Interconnect Switch. The GbE Interconnect Switch can use IGMP snooping to configure
ports dynamically, so that IP multicast traffic is forwarded only to those ports associated with
IP multicast hosts, based on membership information.
IGMP snooping allows the GbE Interconnect Switch to recognize IGMP queries and reports
sent between network stations or devices and an IGMP host that belongs to a specific
multicast group. When enabled for IGMP snooping, the GbE Interconnect Switch can open or
close a port to a specific device based on IGMP messages passing through the module. This
feature further limits unnecessary broadcasts. The GbE Interconnect Switch can be
configured to make queries using either IGMP version 1 or version 2.
When IGMP snooping is enabled globally on the GbE Interconnect Switch, you can enable or
disable individual VLANs for IGMP snooping.
When IGMP snooping is enabled, any port receiving IGMP response packets will forward
them to the CPU, and the CPU sets this port as a member of the corresponding multicast
address.
The GbE Interconnect Switch supports three multicast group address filtering modes for
making forwarding decisions regarding multicast packets.
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Forward all group addresses—All multicast packets destined for all group MAC
addresses are forwarded according to the VLAN rules.
Forward all unregistered group addresses—All multicast packets with group MAC
address registration entries existing in the multicast table (both static multicast and group
multicast created by IGMP snooping) are forwarded to member ports. If the group MAC
address does not exist in the multicast table, packets are forwarded according to the
VLAN rules.
Filter all unregistered group addresses—All multicast packets with group MAC
addresses are forwarded only if such forwarding is explicitly permitted by a group
address entry in the multicast table. If the group MAC address exists in the multicast
table, then the packets are forwarded using the port member list for that entry. If the
group MAC address does not exist in the multicast table, the packets are dropped.
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