Igmp Snooping Example - Cisco Catalyst 2000 Configuration Handbook

144 Cisco LAN Switching Configuration Handbook
(Optional) Statically identify a multicast router port:
5.
(interface) ip igmp snooping mrouter {interface {interface interface-number}
| {Port-channel number}}
IGMP snooping automatically detects ports where multicast routers connect. You
can also give a static definition of a multicast router port.
(Optional) Define a static multicast host entry:
6.
(interface) ip igmp snooping static {mac-address} {interface {interface
interface-number}} | {port-channel number}}
The host connected to the specified interface is statically joined to multicast group
mac-address (dotted-triplet format) on the current VLAN interface. On the COS
switch, the static entry can be used until the next reboot (static) or even across the
next reboot (permanent).
(Optional) Act as an IGMP querier.
7.
a. Enable the querier:
b. (Optional) Adjust the query interval:
c. (Optional) Adjust the self-election interval:
If more than one querier is present on a VLAN, only one of them is elected to
remain the querier. If no other general IGMP queries are overheard on the vlan num-
ber for seconds (default 300 seconds), the switch elects itself as the querier.
Tip Querier election takes place by using the source IP address in the general query mes-
sages. For a specific VLAN, switches use the IP address from their VLAN interface as the
IGMP source address. The lowest IP address wins the querier election.

IGMP Snooping Example

IGMP snooping is enabled globally on the COS switch and on specific interfaces on the
IOS switch. IGMP Fast-Leave Processing is enabled. A static entry for IP multicast group
address 224.100.1.35 (MAC address 01-00-5e-64-01-23) is configured that lists switch
(interface) ip igmp snooping querier
By default, the IGMP querier function is disabled. If no other multicast routers
are available and there is no need to route multicast packets on the local network,
the switch can provide the IGMP querier function. Use the enable keyword and
specify the vlan number where the querier will be used.
(global) ip igmp query-interval seconds
The time between general IGMP queries or the query interval on the vlan num-
ber can be set to seconds. (The default is 125 seconds.)
(global) ip igmp query-timeout seconds