Igmp Snooping - Lancom ES-2126+ Manual

LANCOM ES-2126+ und LANCOM ES-2126P
Chapter 4: Operation of Web- based Management
power and then reboot and recover. At this moment, a bunch of switch or
other network device on the LAN will try its best to find the server to get the
services or try to set up the predefined links, they will issue many broadcast
packets in the network.
The switch supports a random delay time for DHCP and boot delay for each
device. This suppresses the broadcast storm while all devices are at booting
stage in the same time. The maximum user-defined delay time is 30 sec. If
DHCP Broadcasting Suppression function is enabled, the delay time is set ran-
domly, ranging from 0 to 30 seconds, because the exactly delay time is com-
puted by the switch itself. The default is "Disable".
4.8

IGMP Snooping

The function, IGMP Snooping, is used to establish the multicast groups to for-
ward the multicast packet to the member ports, and, in nature, avoids wasting
the bandwidth while IP multicast packets are running over the network. This
is because a switch that does not support IGMP or IGMP Snooping can not tell
the multicast packet from the broadcast packet, so it can only treat them all
as the broadcast packet. Without IGMP Snooping, the multicast packet for-
warding function is plain and nothing is different from broadcast packet.
A switch supported IGMP Snooping with 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 joined in a specified IP multicast group before.
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