HP V1910 Switch Series User Manual

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multicast group through the port that received the leave group message. After hearing the IGMP
group-specific query, the switch forwards it through all its router ports in the VLAN and all member ports
for that multicast group, and performs the following to the port (in case it is a dynamic member port)
before the member port aging timer of the port expires:
 If any IGMP report in response to the group-specific query is heard on a member port before its
aging timer expires, this means that some host attached to the port is receiving or expecting to
receive multicast data for that multicast group. The switch resets the aging timer of the member port.
 If no IGMP report in response to the group-specific query is heard on a member port before its
aging timer expires, this means that no hosts attached to the port are still listening to that group
address. The switch removes the port from the outgoing port list of the forwarding table entry for that
multicast group when the aging timer expires.
IGMP snooping querier
In an IP multicast network running IGMP, a multicast router or Layer 3 multicast switch is responsible for
sending IGMP general queries, so that all Layer 3 multicast devices can establish and maintain multicast
forwarding entries, thus to forward multicast traffic correctly at the network layer. This router or Layer 3
switch is called an IGMP querier.
However, a Layer 2 multicast switch does not support IGMP, and therefore cannot send general queries
by default. By enabling IGMP snooping on a Layer 2 switch in a VLAN where multicast traffic needs to
be Layer-2 switched only and no multicast routers are present, the Layer 2 switch will act as the IGMP
snooping querier to send IGMP queries, thus allowing multicast forwarding entries to be established and
maintained at the data link layer.
Protocols and standards
 RFC 4541, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) Snooping Switches
Configuring IGMP snooping
Configuration task list
Task Remarks
Enabling IGMP snooping
globally
Required
Disabled by default.
Configuring IGMP snooping
in a VLAN
Required
Enable IGMP snooping in the VLAN and configure the IGMP snooping version
and querier feature.
By default, IGMP snooping is disabled in a VLAN.
IMPORTANT:
 IGMP snooping must be enabled globally before it can be enabled in a
VLAN.
 When you enable IGMP snooping in a VLAN, this function takes effect for
ports in this VLAN only.

HP V1910 Switch Series Specifications

General

Brand	HP
Model	V1910 Switch Series
Category	Switch
Language	English