Catalyst Switch Configuration

Catalyst Switch Configuration
The Catalyst syntax is just as simple as the syntax for the router configuration, if not simpler.
By default, CGMP is turned off on the switch. If you want multicast to work properly, you must
enable CGMP or IGMP Snooping on the switch. Enabling CGMP is done by using the command
set cgmp enable. Here is an example:
Terry_4000> (enable) set cgmp enable
CGMP support for IP multicast enabled.
Terry_4000> (enable)
Terry_4000> (enable) show cgmp statistics
CGMP enabled
CGMP statistics for vlan 1:
valid rx pkts received 6
invalid rx pkts received 0
valid cgmp joins received 6
valid cgmp leaves received 0
valid igmp leaves received 0
valid igmp queries received 0
igmp gs queries transmitted 0
igmp leaves transmitted 0
failures to add GDA to EARL 0
topology notifications received 0
number of packets dropped 0
Terry_4000> (enable)
Configuring IP Multicast Routing 633
After CGMP is enabled, you can look at statistics by using the show cgmp statistics
command. This is all that is needed to enable CGMP on the switch so that it can communicate
with the router.
A CGMP-enabled switch can also be configured to detect IGMPv2 Leave messages generated
by clients. To do this, simply use the command set cgmp leave enable. This command takes
place globally on the switch.
The switch collects multicast group MAC addresses for each group address. To see what
multicast groups your switch knows about, use the command show multicast group cgmp.