Raisecom
ISCOM2600G-HI (A) Series Configuration Guide
8 Multicast
Raisecom Proprietary and Confidential
Copyright © Raisecom Technology Co., Ltd.
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8.3 IGMP Snooping
8.3.1 Introduction
IGMP Snooping is a multicast constraining mechanism running on Layer 2 devices, used for
managing and controlling multicast groups, and implementing Layer 2 multicast.
IGMP Snooping allows the ISCOM2600G-HI series switch to monitor IGMP sessions
between the host and multicast router. When monitoring a group of IGMP Report from host,
the ISCOM2600G-HI series switch will add host-related interface to the forwarding entry of
this group. Similarly, when a forwarding entry reaches the aging time, the ISCOM2600G-HI
series switch will delete host-related interface from the forwarding table.
IGMP Snooping forwards multicast data through Layer 2 multicast entry. When receiving
multicast data, the ISCOM2600G-HI series switch will forward them directly according to the
corresponding receiving interface of the multicast entry, instead of flooding them to all
interfaces, to save bandwidth of the ISCOM2600G-HI series switch effectively.
IGMP Snooping establishes a Layer 2 multicast forwarding table, of which entries can be
learnt dynamically or configured manually.
8.3.2 Preparing for configurations
Scenario
As shown in Figure 8-5, multiple hosts belonging to a VLAN receive data from the multicast
source. You can enable IGMP Snooping on the Switch that connects the multicast router and
hosts. By listening IGMP packets transmitted between the multicast router and hosts, creating
and maintaining the multicast forwarding table, you can implement Layer 2 multicast.
Figure 8-5
IGMP Snooping networking
Prerequisite
Disable multicast VLAN copy on the ISCOM2600G-HI series switch.