Configuring an RP
An RP can provide services for multiple or all multicast groups. However, only one RP can forward multicast traffic for a multicast group at a moment.
An RP can be manually configured or dynamically elected through the BSR mechanism. For a large-scaled PIM network, configuring static RPs is a tedious job. Generally, static RPs are backups for dynamic RPs to enhance the robustness and operational manageability on a multicast network.
Configuring a static RP
If only one dynamic RP exists on a network, you can configure a static RP to avoid communication interruption caused by single-point failures. The static RP also prevents frequent message exchange between C-RPs and the BSR for RP election.
When you configure static RPs for PIM-SM, follow these restrictions and guidelines:
You can configure the same static RP for different multicast groups by using the same RP address but different ACLs.
You do not need to enable PIM for an interface to be configured as a static RP.
If you configure multiple static RPs for a multicast group, only the static RP with the highest IP address takes effect.
The static RP configuration must be the same on all routers in the PIM-SM domain.
To configure a static RP for PIM-SM:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter PIM view. | pim [ vpn-instance vpn-instance-name ] | N/A |
3. Configure a static RP for PIM-SM. | static-rp rp-address [ acl-number | preferred ] * | By default, no static RPs exist. |
Configuring a C-RP
![[IMPORTANT: ]](images/important.png) | IMPORTANT: When you configure a C-RP, reserve a relatively large bandwidth between the C-RP and other devices in the PIM-SM domain. | |
In a PIM-SM domain, if you want a router to become the RP, you can configure the router as a C-RP. As a best practice, configure C-RPs on backbone routers.
The C-RPs periodically send advertisement messages to the BSR, which collects RP set information. You can configure the interval for sending the advertisement messages.
The holdtime option in C-RP advertisement messages defines the C-RP lifetime for the advertising C-RP. The BSR starts a holdtime timer for a C-RP after the BSR receives an advertisement message. If the BSR does not receive any advertisement message when the timer expires, it regards the C-RP failed or unreachable.
A C-RP policy enables the BSR to filter C-RP advertisement messages by using an ACL that specifies the packet source addresses and multicast groups. It is used to guard against C-RP spoofing. You must configure the same C-RP policy on all C-BSRs in the PIM-SM domain.
To configure a C-RP:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter PIM view. | pim [ vpn-instance vpn-instance-name ] | N/A |
3. Configure a C-RP. | c-rp ip-address [ advertisement-interval adv-interval | group-policy acl-number | holdtime hold-time | priority priority ] * | By default, no C-RPs exist. |
4. (Optional.) Configure a C-RP policy. | crp-policy acl-number | By default, no C-RP policy exists. |
Enabling Auto-RP listening
This feature enables the router to receive Auto-RP announcement and discovery messages and learn RP information. The destination IP addresses for Auto-RP announcement and discovery messages are 224.0.1.39 and 224.0.1.40, respectively.
To enable Auto-RP listening:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter PIM view. | pim [ vpn-instance vpn-instance-name ] | N/A |
3. Enable Auto-RP listening. | auto-rp enable | By default, Auto-RP listening is disabled. |