User Manual Managed Switches
147
Network with multicast filtering
Hosts only receive dedicated traffic from other hosts belonging to the same group.
The Weidmüller switch supports both automatic multicast filtering with IGMP (Internet Group
Management Protocol) Snooping and manual multicast filtering by adding static multicast IP
addresses.
It additionally supports MVR (Multicast VLAN Registration) to enable Multicast traffic across different
VLANs.
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 configure its filters accordingly.
Querier Mode
Querier mode allows the Weidmüller switch to work as the Querier if it has the lowest IP address on
the subnetwork to which it belongs. Enable query mode to run multicast sessions on a network that
does not contain IGMP routers (or queriers).
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.
•
The IP router (or querier) periodically sends query packets to all end-stations on the LANs or
VLANs that are connected to it. For networks with more than one IP router, the router with the
lowest IP address is the querier. A switch with IP address lower than the IP address of any other
IGMP querier connected to the LAN or VLAN can become the IGMP querier.