Igmp Snooping - WAGO 852-1305 Manual

58 Enhanced Features
7.2.2

IGMP Snooping

"IGMP Snooping" ("Internet Group Management Protocol Snooping") is used
for multicast data traffic. The switch can passively "snoop" on IGMP packets
transmitted between IP multicast routers/switches and IP multicast hosts to learn
the IP multicast group membership. "IGMP Snooping" allows a switch to detect
multicast groups without a user having to manually configure them.
It checks IGMP packets passing through it, reads the group registration
information and configures multicasting accordingly.
The switch forwards multicast traffic to its multicast destination groups (that it has
detected from "IGMP Snooping" or that you have manually configured) to ports
that are members of those groups. "IGMP Snooping" generates no additional
network traffic, allowing you to significantly reduce multicast traffic passing
through the switch.
The switch can perform "IGMP Snooping" on up to 4094 VLANs. You can
configure the switch to automatically detect multicast group membership in all
VLANs. The switch then performs "IGMP Snooping" on the first VLANs that
send IGMP packets.
This is referred to as "Auto Mode". Alternatively, you can specify the VLANs
that "IGMP Snooping" should be performed on. This is referred to as "Fixed
Mode". In "Fixed Mode", the switch does not detect multicast group membership
of any VLANs other than those explicitly added as an "IGMP Snooping" VLAN.
Immediate Leave
If you enable the "IGMP Immediate Leave" function, the switch immediately
deletes a port when it receives a "Leave message" with IGMP Version 2 on that
port. You should use the "Immediate Leave" function only when there is a single
receiver present on every port in the VLAN ("Immediate Leave" is only supported
on IGMP Version 2 hosts).
The switch uses the "Immediate Leave" function with "IGMP Snooping" to
remove an interface from the forwarding table that sends a "Leave Message"
without the switch sending group-specific queries to the interface. The VLAN
interface is deleted from the multicast tree for the multicast group specified in the
original "Leave Message". "Immediate Leave" ensures optimal bandwidth
management for all hosts in a switched network, even when multiple multicast
groups are simultaneously in use.
WAGO-ETHERNET-Zubehör 852
852-1305 8/4-Port 100BASE-T/1000BASE-SX/LX
Manual
1.1.0