Configuring the SSM map table

Configure the SSM map table to map groups to their sending source. SSM maps cannot conflict with static source groups. After you configure an SSM map or a static source group, the switch performs a consistency check to make sure no conflicts exist. You can map one group (G) to different sources or multiple sources to the same group for both static source group and an SSM map.

About this task

The consistency check applies to all SSM map entries, even if they are disabled. If you disable an entry, it becomes inactive. If you do not delete the entry, you can reenable it later.

After you disable an SSM map, the switch stops multicast traffic from the specified source to the specified group. You can use this static configuration as a security feature to block traffic from a certain source to a specific group.

You can configure IGMP on a VRF instance the same way you configure the Global Router except that you must use VRF Router Configuration mode.

Procedure

  1. Enter Global Configuration mode:

    enable

    configure terminal

  2. Enable the SSM map table for all static entries:

    ip igmp ssm-map all

  3. Create a static entry for a specific group:

    ip igmp ssm-map {A.B.C.D} {A.B.C.D} enable

Example

Create an SSM map table entry for the multicast group 234.0.1.0 and the source at 192.32.99.151. Configure the administrative state to enable all the static SSM map table entries.

Switch:1(config)#ip igmp ssm-map 234.0.1.0 192.32.99.151
Switch:1(config)#ip igmp ssm-map all

Variable definitions

Use the data in the following table to use the ip igmp ssm-map command.

Variable

Value

{A.B.C.D} {A.B.C.D}

Creates a static SSM channel table entry by specifying the group and source IP addresses. The IP address is an IP multicast address within the SSM range. The source IP address is an IP host address that sends traffic to the group.

{A.B.C.D} enable

Enables the administrative state for a specific entry (group). This variable does not affect the dynamically learned entries.

This state determines whether the switch uses the static entry or saves it for future use. The default is enable for each entry.