Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

 
ON THIS PAGE
 

Configuring PIM Bootstrap Router

Understanding the PIM Bootstrap Router

To determine which router is the rendezvous point (RP), all routers within a PIM sparse-mode domain collect bootstrap messages. A PIM sparse-mode domain is a group of routers that all share the same RP router. The domain bootstrap router initiates bootstrap messages, which are sent hop by hop within the domain. The routers use bootstrap messages to distribute RP information dynamically and to elect a bootstrap router when necessary.

Configuring PIM Bootstrap Properties for IPv4

For correct operation, every multicast router within a PIM domain must be able to map a particular multicast group address to the same Rendezvous Point (RP). The bootstrap router mechanism is one way that a multicast router can learn the set of group-to-RP mappings. Bootstrap routers are supported in IPv4 and IPv6.

Note:

For legacy configuration purposes, there are two sections that describe the configuration of bootstrap routers: one section for both IPv4 and IPv6, and this section, which is for IPv4 only. The method described in Configuring PIM Bootstrap Properties for IPv4 or IPv6 is recommended. A commit error occurs if the same IPv4 bootstrap statements are included in both the IPv4-only and the IPv4-and-IPv6 sections of the hierarchy. The error message is “duplicate IPv4 bootstrap configuration.”

To determine which routing device is the RP, all routing devices within a PIM domain collect bootstrap messages. A PIM domain is a contiguous set of routing devices that implement PIM. All are configured to operate within a common boundary. The domain's bootstrap router initiates bootstrap messages, which are sent hop by hop within the domain. The routing devices use bootstrap messages to distribute RP information dynamically and to elect a bootstrap router when necessary.

You can configure bootstrap properties globally or for a routing instance. This example shows the global configuration.

To configure the bootstrap router properties:

  1. Configure the bootstrap priority.

    By default, each routing device has a bootstrap priority of 0, which means the routing device can never be the bootstrap router. A priority of 0 disables the function for IPv4 and does not cause the routing device to send bootstrap router packets with a 0 in the priority field. The routing device with the highest priority value is elected to be the bootstrap router. In the case of a tie, the routing device with the highest IP address is elected to be the bootstrap router. A simple bootstrap configuration assigns a bootstrap priority value to a routing device.

  2. (Optional) Create import and export policies to control the flow of IPv4 bootstrap messages to and from the RP, and apply the policies to PIM. Import and export policies are useful when some of the routing devices in your PIM domain have interfaces that connect to other PIM domains. Configuring a policy prevents bootstrap messages from crossing domain boundaries. The bootstrap-import statement prevents messages from being imported into the RP. The bootstrap-export statement prevents messages from being exported from the RP.
  3. Configure the policies.
  4. Monitor the operation of PIM bootstrap routing devices by running the show pim bootstrap command.

See Also

Configuring PIM Bootstrap Properties for IPv4 or IPv6

For correct operation, every multicast router within a PIM domain must be able to map a particular multicast group address to the same Rendezvous Point (RP). The bootstrap router mechanism is one way that a multicast router can learn the set of group-to-RP mappings. Bootstrap routers are supported in IPv4 and IPv6.

Note:

For legacy configuration purposes, there are two sections that describe the configuration of bootstrap routers: one section for IPv4 only, and this section, which is for both IPv4 and IPv6. The method described in this section is recommended. A commit error occurs if the same IPv4 bootstrap statements are included in both the IPv4-only and the IPv4-and-IPv6 sections of the hierarchy. The error message is “duplicate IPv4 bootstrap configuration.”

To determine which routing device is the RP, all routing devices within a PIM domain collect bootstrap messages. A PIM domain is a contiguous set of routing devices that implement PIM. All devices are configured to operate within a common boundary. The domain's bootstrap router initiates bootstrap messages, which are sent hop by hop within the domain. The routing devices use bootstrap messages to distribute RP information dynamically and to elect a bootstrap router when necessary.

You can configure bootstrap properties globally or for a routing instance. This example shows the global configuration.

To configure the bootstrap router properties:

  1. Configure the bootstrap priority.

    By default, each routing device has a bootstrap priority of 0, which means the routing device can never be the bootstrap router. The routing device with the highest priority value is elected to be the bootstrap router. In the case of a tie, the routing device with the highest IP address is elected to be the bootstrap router. A simple bootstrap configuration assigns a bootstrap priority value to a routing device.

    Note:

    In the IPv4-only configuration, specifying a bootstrap priority of 0 disables the bootstrap function and does not cause the routing device to send BSR packets with a 0 in the priority field. In the configuration shown here, specifying a bootstrap priority of 0 does not disable the function, but causes the routing device to send BSR packets with a 0 in the priority field. To disable the bootstrap function in the IPv4 and IPv6 configuration, delete the bootstrap statement.

  2. (Optional) Create import and export policies to control the flow of bootstrap messages to and from the RP, and apply the policies to PIM. Import and export policies are useful when some of the routing devices in your PIM domain have interfaces that connect to other PIM domains. Configuring a policy prevents bootstrap messages from crossing domain boundaries. The import statement prevents messages from being imported into the RP. The export statement prevents messages from being exported from the RP.
  3. Configure the policies.
  4. Monitor the operation of PIM bootstrap routing devices by running the show pim bootstrap command.

See Also

Example: Rejecting PIM Bootstrap Messages at the Boundary of a PIM Domain

In this example, the from interface so-0-1/0 then reject policy statement rejects bootstrap messages from the specified interface (the example is configured for both IPv4 and IPv6 operation):

Example: Configuring PIM BSR Filters

Configure a filter to prevent BSR messages from entering or leaving your network. Add this configuration to all routers:

Related Documentation