Table of Contents
Advertisement
5.13
IGMP Snooping
IGMP snooping is used to establish the multicast groups to forward multicast packets to
member ports. IGMP snooping avoids wasting the bandwidth while IP multicast packets are
running over the network. A switch that does not support IGMP snooping cannot tell a multicast
packet from broadcast packet, so it treats them as broadcast packets. Without IGMP snooping,
the multicast packet forwarding function is no different from broadcast packets.
A switch with IGMP snooping supports the functions of query, report and leave. A type of packet
exchanged between IP multicast router/switch and IP multicast host can update the information
of the multicast table when a member (port) joins or leaves an IP multicast destination address.
With this function, once a switch receives an IP multicast packet, it will forward the packet to the
members who had joined a specified IP multicast group.
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. Enabling IGMP with either passive or active
mode, you can monitor the IGMP snooping information, which contains the multicast member list
with the multicast groups, VID and member port.
Parameter description:
IGMP snooping mode selection:
The switch supports three kinds of IGMP Snooping status, including "Passive", "Active" and
"Disable".
Disable:
Use "Disable" mode to disable IGMP Snooping function.
Default: Disable
Active:
In Active mode, IGMP snooping will periodically issue the Membership Query message
to all attached hosts and gather the membership report message to update the database
of the multicast table. This also reduces the unnecessary multicast traffic.
Waters Network Systems
Figure 5.25 – IGMP Snooping
User's Manual
GSM-2108/GSM-1008SFP
Page 54
Advertisement
Table of Contents
