Configure PIM bidirectional neighbor filters

Configure PIM bidirectional neighbor filters to control which neighbor devices participate in the Designated Forwarder (DF) election for bidirectional multicast routing. This helps ensure proper multicast traffic forwarding in the network.

A PIM bidirectional neighbor filter is an ACL that defines the neighbor devices that can participate in the Designated Forwarder (DF) election. If you do not configure a PIM bidirectional neighbor filter for an interface, there are no restrictions. If you configure a PIM bidirectional neighbor filter, only neighbors permitted by the ACL can participate in the DF election process.

Bidirectional PIM allows multicast routers to keep reduced state information. All multicast routers in a segment must be bidirectionally enabled to elect a DF.

When a PIM bidirectional neighbor filter is enabled, the routers permitted by the ACL are considered to be bidirectionally capable. Therefore, the following is true:

  • If a permitted neighbor does not support bidirectional mode, the DF election does not occur.

  • If a denied neighbor supports bidirectional mode, the DF election does not occur.

  • If a denied neighbor does not support bidirectional mode, the DF election can occur.

Procedure

Step 1

Choose Devices > Device Management, and edit the Firewall Threat Defense device.

Step 2

Choose Multicast Routing > PIM.

Step 3

On Bidirectional Neighbor Filter, click Add or Edit.

Use the Add PIM Bidirectional Neighbor Filter dialog box to create ACL entries for the PIM bidirectional neighbor filter ACL. Use the Edit PIM Bidirectional Neighbor Filter dialog box to change existing parameters.

Step 4

Configure these options:

  • In the Interface drop-down list, select the interface for which you want to configure the PIM bidirectional neighbor filter ACL entry.

  • From the Standard Access List drop-down list, select a standard ACL or click Add (add icon) to create a new standard ACL. Refer to Configure a standard ACL object for the procedure.

    Note

    Choosing Allow in the Add Standard Access List Entry dialog box lets the specified devices participate in the DR election process. Choosing Block prevents the specified devices from participating in the DR election process.

Step 5

Click OK to save the PIM bidirectional neighbor filter configuration.