Configuring Register Message Filters on a PIM RP and DR

PIM register messages are sent to the rendezvous point (RP) by a designated router (DR). When a source for a group starts transmitting, the DR sends unicast PIM register packets to the RP.

• Notify the RP that a source is sending to a group.
• Deliver the initial multicast packets sent by the source to the RP for delivery down the shortest-path tree (SPT).

The PIM RP keeps track of all active sources in a single PIM sparse mode domain. In some cases, you want more control over which sources an RP discovers, or which sources a DR notifies other RPs about. A high degree of control over PIM register messages is provided by RP or DR register message filtering. Message filtering prevents unauthorized groups and sources from registering with an RP router.

You configure RP or DR register message filtering to control the number and location of multicast sources that an RP discovers. You can apply register message filters on a DR to control outgoing register messages, or apply them on an RP to control incoming register messages.

When anycast RP is configured, all RPs in the anycast RP set need to be configured with the same register message filtering policy.

You can configure message filtering globally or for a routing instance. These examples show the global configuration.

1. On the RP, configure the policy.
   [edit policy-options policy-statement incoming-policy-for-rp from]user@host# set route-filter 224.1.1.0/24 orlongeruser@host# set source-address-filter 10.10.94.2/32 exactuser@host# set then rejectuser@host# exit
2. Apply the policy to the RP.
   [edit protocols pim rp]user@host# set rp-register-policy incoming-policy-for-rpuser@host# set local address 10.10.10.5user@host# exit

1. On the DR, configure the policy.
   [edit policy-options policy-statement outgoing-policy-for-rp]user@host# set from route-filter 224.1.1.0/24 orlongeruser@host# set from source-address-filter 10.10.10.1/32 exactuser@host# set then rejectuser@host# exit
2. Apply the policy to the DR.

   The static address is the address of the RP to which you do not want the DR to send the filtered register messages.

   [edit protocols pim rp]user@host# set dr-register-policy outgoing-policy-for-druser@host# set static 10.10.10.3user@host# exit

1. On the RP, configure the policies.
   [edit policy-options policy-statement reject_224_1_1_1]user@host# set from route-filter 224.1.1.0/24 orlongeruser@host# set from source-address-filter 10.10.94.2/32 exactuser@host# set then rejectuser@host# exit
   [edit policy-options policy-statement accept_224_1_1_5]user@host# set term one from route-filter 224.1.1.5/32 exactuser@host# set term one from source-address-filter 10.10.94.2/32 exactuser@host# set term one then acceptuser@host# set term two then rejectuser@host# exit
2. Apply the policies to the RP.
   [edit protocols pim rp]user@host# set rp-register-policy [ reject_224_1_1_1 | accept_224_1_1_5 ]user@host# set local address 10.10.10.5