Cisco Catalyst 2960 Series, Configuration Manual

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Preemption Mode : off
Multicast Fast Convergence : Off
Bandwidth : 100000 Kbit (Gi1/0/11), 100000 Kbit (Gi1/0/12)
Mac Address Move Update Vlan : auto
This output shows a querier for VLANs 1 and 401, with their queries reaching the switch through
GigabitEthernet1/0/11:
Switch# show ip igmp snooping querier
Vlan IP Address IGMP Version Port
-------------------------------------------------------------
1
1.1.1.1 v2 Gi1/0/11
401 41.41.41.1 v2 Gi1/0/11
This example is output for the show ip igmp snooping mrouter command for VLANs 1 and 401:
Switch# show ip igmp snooping mrouter
Vlan ports
---- -----
1 Gi1/0/11(dynamic), Gi1/0/12(dynamic)
401 Gi1/0/11(dynamic), Gi1/0/12(dynamic)
Similarly, both Flex Links ports are part of learned groups. In this example, GigabitEthernet2/0/11 is a
receiver/host in VLAN 1, which is interested in two multicast groups:
Switch# show ip igmp snooping groups
Vlan Group Type Version Port List
-----------------------------------------------------------------------
1
228.1.5.1 igmp v2 Gi1/0/11, Gi1/0/12, Gi2/0/11
1 228.1.5.2 igmp v2 Gi1/0/11, Gi1/0/12, Gi2/0/11
When a host responds to the general query, the switch forwards this report on all the mrouter ports. In this
example, when a host sends a report for the group 228.1.5.1, it is forwarded only on GigabitEthernet1/0/11,
because the backup port GigabitEthernet1/0/12 is blocked. When the active link, GigabitEthernet1/0/11, goes
down, the backup port, GigabitEthernet1/0/12, begins forwarding.
As soon as this port starts forwarding, the switch sends proxy reports for the groups 228.1.5.1 and 228.1.5.2
on behalf of the host. The upstream router learns the groups and starts forwarding multicast data. This is the
default behavior of Flex Links. This behavior changes when the user configures fast convergence using the
switchport backup interface gigabitEthernet 1/0/12 multicast fast-convergence command. This example
shows turning on this feature:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#
interface gigabitEthernet 1/0/11
Switch(config-if)# switchport backup interface gigabitEthernet 1/0/12 multicast
fast-convergence
Switch(config-if)#
exit
Switch# show interfaces switchport backup detail
Switch Backup Interface Pairs:
Active
Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet1/0/11
GigabitEthernet1/0/12 Active Up/Backup Standby
Preemption Mode : off
Multicast Fast Convergence : On
Bandwidth : 100000 Kbit (Gi1/0/11), 100000 Kbit (Gi1/0/12)
Mac Address Move Update Vlan : auto
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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Configuration Examples for Flex Links