Configuring a Dynamic RP

In a PIM-SM domain, you can select several PIM devices and configure Candidate-RPs (C-RPs) on the devices. Then, a Rendezvous Point (RP) is elected from these C-RPs. The Candidate-BSRs (C-BSRs) should also be configured and a BootStrap router (BSR) is elected from these C-BSRs. The BSR is responsible for collecting and advertising the C-RP information on the network. The system supports the auto-RP listening function.

Context

Dynamic RPs apply to large networks that require high availability and maintainability. Static RPs apply to small- and medium-sized networks that require low device performance and use stable configurations. For detailed configurations, see Configuring a Static RP.

The configuration is applicable only to the dynamic RP. If you want to use the static RP in the network, skip the configuration.

Procedure

Access the system view.
system-view
Create a basic ACL and access its view.
acl [ number ] acl-number [ vpn-instance vpn-instance-name ]
Configure rules for the basic ACL.
rule [ rule-id ] { deny | permit } source { source-ip-address { 0 | source-wildcard } | address-set address-set-name | any }

Use parameter source to define the multicast group range to be served by the C-RP.
Return to the system view.
quit
Access the PIM view.
pim [ vpn-instance vpn-instance-name ]
Configure the C-RP.
c-rp interface-type interface-number [ group-policy basic-acl-number | priority priority | holdtime hold-interval | advertisement-interval adv-interval ] ^*
- interface-type interface-number: specifies the interface where the C-RP resides. The interface must be configured with PIM-SM.
  
  To avoid frequent protocol changes caused by interface flapping, using loopback interfaces is recommended.
- group-policy basic-acl-number: specifies the multicast group permitted by ACL and served by the C-RP. By default, C-RP serves all multicast groups.
- priority priority: specifies the priority for electing C-RP. The greater is the value, the lower is the priority. By default, it is 0.
  
  In the RP election, the C-RP with the highest priority wins. In case of the same priority, the hash function is used and the C-RP with the greatest hash value wins. In case of the same priority and the same hash value, the C-RP with the highest IP address wins.
  
  If the address borrowing is configured, it is not recommended to configure C-RP on the interfaces that have the same addresses. If the priorities of the interfaces are different, the BSR considers that the C-RP configuration is repeatedly modified.
- holdtime hold-interval: specifies the interval during which the BSR waits for the Advertisement message from the C-RP. By default, the interval is 150 seconds.
- advertisement-interval adv-interval: specifies the interval during which the C-RP sends the Advertisement message. By default, the interval is 60 seconds.
- If no ACL is configured, the C-RP serves all multicast groups of 224.0.0.0/4.
- If an ACL is configured, the device uses configured ACL rules to filter multicast groups to be served by the C-RP.
  - If a multicast group matches an ACL rule and the action is permit, the C-RP serves this multicast group.
  - If a multicast group matches an ACL rule and the action is deny, the C-RP does not serve this multicast group.
  - If a multicast group does not match any ACL rule or if a specified ACL does not exist or does not contain rules, the C-RP serves all multicast groups of 224.0.0.0/4.
Configure the C-BSR.
c-bsr interface-type interface-number [ hash-length [ priority ] ]
- interface-type interface-number: specifies the interface where the C-BSR resides. The interface must be configured with the PIM-SM.
- hash-length: specifies the length of the hash. According to the G, C-RP address, and the value of hash-length, FWs calculate the C-RPs that have the same priority and require to serve G by operating hash functions, and compare the calculation results. The C-RP with the greatest calculated value functions as the RP that serves G.
- priority: specifies the priority used by FWs to join the BSR election. The greater is the value, the higher is the priority. By default, it is 0.
  
  In the BSR election, the C-BSR with the highest priority wins. In the case of the same priority, the C-BSR with the largest IP address wins.
(Optional) Enable BSR message fragmentation.
bsm semantic fragmentation

It is recommended that you enable BSR message fragmentation on all devices on the network because BSR message fragmentation can solve the problem faced by IP fragmentation that all fragments become unavailable due to loss of fragment information.