Configuring PIM Bootstrap Properties

Configuring the Routing Device’s IPv4 Bootstrap Router Priority

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 originates 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.

By default, the routing device has a bootstrap priority of 0, which means the routing device can never be the bootstrap router. To modify this priority, include the bootstrap-priority statement. 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 simply assigns a bootstrap priority value to a routing device.

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

Filtering PIM IPv4 Bootstrap Messages

You can create import and export policies to control the flow of IPv4 bootstrap messages to and from the RP, and apply them to PIM. To apply one or more import policies to IPv4 bootstrap messages imported into the RP, include the bootstrap-import statement:

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

To apply one or more export policies to IPv4 bootstrap messages exported from the RP, include the bootstrap-export statement:

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

Note: The bootstrap-priority, bootstrap-import, and bootstrap-export statements support IPv4 only. A priority of 0 disables the function for IPv4 and does not cause the routing device to send BSR packets with a 0 in the priority field.

Configuring the Routing Device’s Bootstrap Router Priority

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 originates 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.

The bootstrap configuration hierarchy supports both IPv4 and IPv6 multicasting. It can be combined with the bootstrap statements supported in IPv4 only, as long as the added statements are used for IPv6 only, but this is not recommended. There is a change in the meaning of the bootstrap priority when the value is set to 0.

In the IPv4 configuration hierarchy, specifying the value 0 (zero) for the bootstrap-priority statement disables the function for IPv4 and does not cause the routing device to send BSR packets with a 0 in the priority field (for more information, see Configuring the Routing Device’s IPv4 Bootstrap Router Priority). In the combined IPv4 and IPv6 configuration hierarchy, specifying the value 0 for the priority statement 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 hierarchy, delete the configuration statements.

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.”

We recommend that legacy IPv4-only configurations be converted to the IPv4 and IPv6 configuration hierarchy.

To modify the bootstrap priority for IPv4 or IPv6, include the priority statement for the appropriate address family: inet for IPv4 and inet6 for IPv6. 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.

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

The following example sets bootstrap priority to 1 for both IPv4 and IPv6 multicasts:

An error results when the configuration at this hierarchy level includes both these statements and the bootstrap-priority statement.

Filtering PIM Bootstrap Messages

You can create import and export policies to control the flow of bootstrap messages to and from the RP, and apply them to PIM. To apply one or more import policies to bootstrap messages imported into the RP, include the import statement:

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

To apply one or more export policies to bootstrap messages exported from the RP, include the export statement:

For a list of the hierarchy levels at which you can include this statement, see the statement summary section for this statement.

For an example, see Example: Rejecting PIM Bootstrap Messages at the Boundary of a PIM Domain.

Note: The bootstrap statement stanza supports both IPv4 and IPv6. A 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, delete the configuration statements.