33.1.4 Configuring Multicast Router Ports

(1) Static configuration

Points to note

When a multicast router is connected within a VLAN for which IGMP snooping is set, specify the settings below for the VLAN interface configuration mode of the corresponding VLAN. This example shows a multicast router connected to a Gigabit Ethernet interface on port 1/0/1 of VLAN2.

Command examples

1. (config)# interface vlan 2

   (config-if)# ip igmp snooping mrouter interface gigabitethernet 1/0/1

   Switch to VLAN interface configuration mode of VLAN2 and specify 1/0/1 for the multicast router port.

(2) Enabling multicast router port auto-learning

Points to note

When the multicast router port auto-learning facility is used in VLAN for which IGMP snooping is set, configure the following settings in VLAN interface configuration mode of the applicable VLAN: This example shows the case where IGMP monitoring and PIM monitoring are performed simultaneously.

Command examples

1. (config)# interface vlan 2

   (config-if)# ip igmp snooping mrouter discovery igmp

   Switches to VLAN interface configuration mode of VLAN2, enables multicast router port auto-learning, and specifies IGMP for the monitoring target.

2. (config-if)# ip igmp snooping mrouter discovery pim

   Enable multicast router port auto-learning and specify PIM for monitoring.

Notes

When changing the multicast router port setting method, multicast forwarding may stop. Therefore, change the setting method according to the procedure described in (3) Changing from static configuration to automatic learning and (4) Changing from automatic learning to static configuration.

(3) Changing Static Configuration to Auto Learn

Points to note

To change from static configuration to automatic learning, execute in the following order:

1. Enable Auto Learning

2. After IGMP Query interval of the applicable network has elapsed, check the auto-learned result.

3. Remove Static Configuration

For example, VLAN2 changes from static configuration to auto-learn (IGMP monitoring).

Command examples

1. (config)# interface vlan 2

   (config-if)# ip igmp snooping mrouter discovery igmp

   Switches to VLAN interface configuration mode of VLAN2 and enables multicast router port auto-learning (IGMP monitoring).

2. (config-if)# save

   (config-if)# top

   (config)# exit

   # show igmp-snooping mrouter

   Total entry: 1
   VLAN ID: 2
     Port        IP address         Type    Expire
     1/0/1       192.168.11.100     IGMP    04:08

   #

   Switches from configuration mode to administrator mode.

   After IGMP Query interval of VLAN2 has elapsed, execute an operation command show igmp-snooping mrouter to verify that the multicast router ports are automatically configured.

3. # configure

   (config)# interface vlan 2

   (config-if)# no ip igmp snooping mrouter interface gigabitethernet 1/0/1

   Switches from administrator mode to configuration mode.

   Deletes the static configuration of VLAN2 by entering VLAN interface configuration mode of VLAN2.

(4) Changing Auto Learn to Static Configuration

Points to note

To change from auto learning to static configuration, execute the commands in the following order:

1. Perform static configuration

2. Disable automatic learning

For example, VLAN2 changes from auto-learn (IGMP monitoring) to static configuration.

Command examples

1. (config)# interface vlan 2

   (config-if)# ip igmp snooping mrouter interface gigabitethernet 1/0/1

   Switches to VLAN interface configuration mode of VLAN2, and configures 1/0/1 statically for the multicast router port.

2. (config-if)# no ip igmp snooping mrouter discovery igmp

   Disables auto-learning (IGMP monitoring) of VLAN2.