Alloy Computer Products GSM-8T16SFP - Manual (Page 57)

GSM Series User Manual
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Alloy Computer Products Pty Ltd Copyright ©2006
3-7. IGMP Snooping
IGMP Snooping is used to establish multicast groups to forward multicast packets to each of the
multicast member ports, and, in nature, avoids wasting bandwidth with IP multicast packets. If a
switch does not support IGMP or IGMP Snooping it can not tell a multicast packet from a
broadcast packet, so it will treat them all as broadcast packets. Without IGMP Snooping,
multicast packets are treated as broadcast packets, therefore increasing the overall traffic on your
network.
The GSM Series switches support all functions of IGMP Snooping including query, report and
leave. IGMP Snooping is used by the switch to learn who belongs to a multicast group and also
update the multicast table within the switch with new multicast members. Once the switch has
learned who belongs to the multicast group all packets forwarded to a multicast address will be
forwarded to all members belonging to the multicast group.
3-7-1. Status
Fig. 3-26
Function name:
IGMP Snooping
Function description:
IGMP is used to snoop the status of IP multicast groups and display its associated
information in both tagged VLAN and non-tagged VLAN networks. By enabling IGMP
with either passive or active mode, you can monitor the IGMP snooping information,
which contains information about the multicast member list including the multicast
groups, VID and member ports.
Parameters description:
Snooping Mode:
The GSM Series switches support both Active and Passive modes, IGMP
can also be disabled.
Default: Disable