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Connecting VLAN Groups
The switch supports intra-VLAN communication using wire-speed
switching. However, if you have devices in separate VLANs that
must communicate, and it is not practical to include these devices
in a common VLAN, then the VLANs can be connected via a
Layer 3 switch (such as the SMC6716L3) or router.
Multicast Filtering
Multicasting sends data to a group of nodes instead of a single
destination. The simplest way to implement multicasting is to
broadcast data to all nodes on the network. However, such an
approach wastes a lot of bandwidth if the target group is small
compared to overall the broadcast domain.
Since applications such as video conferencing and data sharing are
more widely used today, efficient multicasting has become vital. A
common approach is to use a group registration protocol that lets
nodes join or leave multicast groups. A switch or router can then
easily determine which ports contain group members and send data
out to those ports only. This procedure is called multicast filtering.
The purpose of multicast filtering is to optimize a switched
network's performance, so multicast packets will only be
forwarded to those ports containing multicast group hosts or
multicast routers/switches instead of flooding to all ports in the
subnet (VLAN). The TigerSwitch 10/100 supports multicast filtering
by passively monitoring IGMP Query and Report messages.
IGMP Snooping
A Layer 2 switch can passively snoop on IGMP Query and Report
packets transferred between IP Multicast Routers/Switches and IP
Multicast host groups to learn the IP Multicast group members. It
simply monitors the IGMP packets passing through it, picks out
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