AirLive SNMP-24MGB - Manual (Page 168)

4. Web Management in SNMP-24MGB
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AirLive SNMP-24MGB User’s Manual
The destination enable means the monitored port egress traffic will be copied to
monitoring port.
4.16 Multicast
The function, Multicast, is used to establish the multicast groups to forward 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
forwarding 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.
The packets will be discarded by the IGMP Snooping if the user transmits multicast packets
to the multicast group that had not been built up in advance.
4.16.1 IGMP Mode
Function name:
IGMP Mode
Function description:
IGMP mode to select the switch to issue IGMP host messages on behalf of hosts that
the system discovered through standard IGMP interfaces. The switch acts as a proxy
or snooping
for its hosts.