2.3. Configuring Multicast Parameters with CLI
This section provides information to configure multicast, IGMP, and PIM.
2.3.1. Multicast Configuration Overview
7210 SAS routers use IGMP to manage membership for a specific multicast session. IGMP is not enabled by default. The IGMP context is not operational until at least one IGMP interface is specified in the context, at which time the interface is enabled for IGMP.
Traffic can only flow away from the router to an IGMP interface, and to and from a PIM interface. A router directly connected to a source must have PIM enabled on the interface to that source. In a network, traffic travels from PIM interface to PIM interface, and arrives on an IGMP-enabled interface.
The IGMP CLI context allows you to specify an existing IP interface and modify the interface-specific parameters. Static IGMP group memberships can be configured to test multicast forwarding without a receiver host. When IGMP static group membership is enabled, data is forwarded to an interface without receiving membership reports from host members.
When static IGMP group entries on point-to-point links that connect routers to a rendezvous point (RP) are configured, the static IGMP group entries do not generate join messages toward the RP. When a host needs to receive multicast sessions, it sends a join message for each multicast group it needs to join. Then, a leave message may be sent for each multicast group it no longer wishes to participate with.
A multicast router keeps a list of multicast group memberships for each attached network, and an interval timer for each membership. Hosts issue a Multicast Group Membership Report when they want to receive a multicast session. The reports are sent to all multicast routers.
PIM is not enabled by default. Because it is an interface function, PIM is not operational until at least one interface is specified in the PIM context, at which time the interface is enabled for PIM. When PIM is enabled, data is forwarded to network segments with active receivers that have explicitly requested the multicast group.
2.3.2. Basic Configuration
Perform the following basic multicast configuration tasks.
For IGMP:
- enable IGMP (required)
- configure IGMP interfaces (required)
- specify the IGMP version on the interface (optional)
- configure static (S,G)/(*,G) (optional)
- configure SSM translation (optional)
For PIM:
- enable PIM (required)
- add interfaces so the protocol establishes adjacencies with the neighboring routers (required)
- configure a way to calculate group-to-RP mapping (required) by either:
- using static group-to-RP mapping
- enabling the candidate RP/bootstrap mechanism on some routers.
- enable unicast routing protocols to learn routes toward the RP/source for reverse path forwarding (required)
- add SSM ranges (optional)
- enable Candidate BSR (optional)
- enable Candidate RP (optional)
- change the hello interval (optional)
- configure route policies (bootstrap-export, bootstrap-import, import join and register)
The following is a sample of enabled IGMP and PIM configuration output.
2.3.3. Common Configuration Tasks
The following sections describe basic multicast configuration tasks.
2.3.4. Configuring IGMP Parameters
This section provides information to configure IGMP parameters.
2.3.4.1. Enabling IGMP
Use the following syntax to enable IGMP.
The following is sample detailed output for an enabled IGMP.
2.3.4.2. Configuring an IGMP Interface
Use the following syntax to configure an IGMP interface.
Use the following syntax to configure IGMP interfaces.
The following is a sample IGMP configuration output.
2.3.4.3. Configuring Static Parameters
Use the following syntax to add an IGMP static multicast source.
Use the following syntax to configure static group addresses and source addresses for the SSM translate group ranges.
The following is a sample configuration output.
Use the following syntax to add an IGMP static starg entry.
Use the following syntax to configure static group addresses and add a static (*,G) entry.
The following is a sample configuration output.
2.3.4.4. Configuring SSM Translation
Use the following CLI syntax to configure IGMP parameters.
The following is a sample command usage to configure IGMP parameters.
The following is a sample configuration for SSM translation.
2.3.5. Configuring PIM Parameters
The following section describes the syntax used to configure the PIM parameters.
2.3.5.1. Enabling PIM
PIM must be enabled on all interfaces for the routing instance; failure to do so might result in multicast routing errors.
Use the following syntax to enable PIM.
The following is a sample detailed output of an enabled PIM.
2.3.5.2. Configuring PIM Interface Parameters
The following shows the command usage to configure PIM interface parameters.
The following is a sample PIM configuration output.
2.3.5.3. Importing PIM Join or Register Policies
The import command provides a mechanism to control the (*,G) and (S,G) state that is created on a router. Import policies are defined in the config>router>policy-options context.
 | Note: In the import policy, if a policy action is not specified in the entry, the default-action takes precedence. In the same way, if there are no entry matches, the default-action takes precedence. If no default-action is specified, the default default-action is executed. |
Use the following syntax to configure PIM parameters.
The following example shows the command usage to apply the policy statement, which does not allow join messages for group 229.50.50.208/32 and source 192.168.0.0/16, but allows join messages for 192.168.0.0/16, 229.50.50.208 (see Configuring Route Policy Components).
The following is a sample PIM configuration output.
2.3.6. Disabling IGMP or PIM
Use the following syntax to disable IGMP and PIM.
The following shows the command usage to disable multicast.
The following is a sample configuration output.