IE-SW-VL08M Series User’s Manual
Featured Functions
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Network with multicast filtering
Hosts only receive dedicated traffic from other hosts belonging to the same group.
Multicast Filtering and IE-SW-VL08M Switch
The Ethernet Switch has three ways to achieve multicast filtering: IGMP (Internet Group
Management Protocol) Snooping, GMRP (GARP Multicast Registration Protocol), and adding a
static multicast MAC manually to filter multicast traffic automatically.
IGMP (Internet Group Management Protocol)
Snooping Mode
Snooping Mode allows your switch to forward multicast packets only to the appropriate ports. The
switch “snoops” on exchanges between hosts and an IGMP device, such as a router, to find those
ports that want to join a multicast group, and then configures its filters accordingly.
Query Mode
Query mode allows the Ethernet Switch to work as the Querier if it has the lowest IP address on the
subnetwork to which it belongs. IGMP querying is enabled by default on the device to help prevent
interoperability issues with some multicast routers that may not follow the lowest IP address
election method. Enable query mode to run multicast sessions on a network that does not contain
IGMP routers (or queriers).
NOTE
The IE-SW-VL08M is compatible with any device that conforms to the IGMP v2 device protocol.
IGMP Multicast Filtering
IGMP is used by IP-supporting network devices to register hosts with multicast groups. It can be
used on all LANs and VLANs that contain a multicast capable IP router, and on other network
devices that support multicast filtering. IGMP works as follows:
1.
The IP router (or querier) periodically sends
query
packets to all end-stations on the LANs or
