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6.2. IGMP Snooping
6.2.1. IGMP Snooping
The IGMP snooping is for multicast traffic. The Switch can passively snoop on IGMP
packets transferred between IP multicast routers/switches and IP multicast hosts to learn
the IP multicast group membership. It checks IGMP packets passing through it, picks out
the group registration information and configures multicasting accordingly. IGMP
snooping allows the Switch to learn multicast groups without you having to manually
configure them.
The Switch can passively snoop on IGMP packets transferred between IP multicast
routers/switches and IP multicast hosts to learn the IP multicast group membership. It
checks IGMP packets passing through it, picks out the group registration information, and
configures multicasting accordingly. IGMP snooping allows the Switch to learn multicast
groups without you having to manually configure them.
The Switch forwards multicast traffic destined for multicast groups (that it has learned from
IGMP snooping or that you have manually configured) to ports that are members of that
group. IGMP snooping generates no additional network traffic, allowing you to
significantly reduce multicast traffic passing through your Switch.
The Switch can perform IGMP snooping on up to 4094 VLANs. You can configure the
Switch to automatically learn multicast group membership of any VLANs. The Switch then
performs IGMP snooping on the first VLANs that send IGMP packets. Alternatively, you
can specify the VLANs that IGMP snooping should be performed on. This is referred to as
fixed mode. In fixed mode the Switch does not learn multicast group membership of any
VLANs other than those explicitly added as an IGMP snooping VLAN.
Configurations:
Users can enable/disable the IGMP Snooping on the Switch. Users also can enable/disable
the IGMP Snooping on a specific VLAN. If the IGMP Snooping on the Switch is disabled,
the IGMP Snooping is disabled on all VLANs even some of the VLAN IGMP Snooping
are enabled.
Default Settings
If received packets are not received after 400 seconds, all multicast entries will be
deleted.
The default global IGMP snooping state is disabled.
The default VLAN IGMP snooping state is disabled for all VLANs.
The unknown multicast packets will be dropped.
The default port Immediate Leave state is disabled for all ports.
The default port Querier Mode state is auto for all ports.
The IGMP snooping Report Suppression is disabled.
Notices: There are a global state and per VLAN states. When the global state is disabled,
the IGMP snooping on the Switch is disabled even per VLAN states are enabled. When the