Cisco Systems 78-11741-02 Specifying the PIM Version, Configuring PIM Version 2 Only, IPC-419

Configuring IP Multicast Routing

Configuring PIM Version 2

Specifying the PIM Version

All systems using Cisco IOS Release 11.3(2)T or later start in PIM Version 2 mode by default. To reenable PIM Version 2 or specify PIM Version 1 for some reason, control the PIM version by using the following command in interface configuration mode:

Command	Purpose
Router(config-if)# ip pim version [1 2]	Configures the PIM version used.

Configuring PIM Version 2 Only

To configure PIM Version 2 exclusively, perform the tasks described in this section. It is assumed that no PIM Version 1 system exists in the PIM domain.

The first task is recommended. If you configure Auto-RP, none of the other tasks is required to run PIM Version 2. To configure Auto-RP, see the section “Configuring Auto-RP” earlier in this chapter.

If you want to configure a BSR, perform the tasks in the following sections. The tasks is the first section are required; the tasks in the remaining sections are optional.

•Configuring PIM Sparse-Dense Mode (Required)

•Defining a PIM Sparse Mode Domain Border Interface (Optional)

•Configuring Candidate BSRs (Optional)

•Configuring Candidate RPs (Optional)

Configuring PIM Sparse-Dense Mode

To configure PIM sparse-dense mode, use the following commands on all PIM routers inside the PIM domain beginning in global configuration mode:

	Command	Purpose
Step 1
	Router(config)# ip multicast-routing	Enables IP multicast routing.
Step 2
	Router(config)# interface type number	Configures an interface.
Step 3
	Router(config-if)#ip pim sparse-dense-mode	Enables PIM on the interface. The sparse-dense mode is
		identical to the implicit interface mode in the PIM Version 2
		specification.

Repeat Steps 2 and 3 for each interface on which you want to run PIM.

Defining a PIM Sparse Mode Domain Border Interface

A border interface in a PIM sparse mode (PIM-SM) domain requires special precautions to avoid exchange of certain traffic with a neighboring domain reachable through that interface, especially if that domain is also running PIM-SM. BSR and Auto-RP messages should not be exchanged between different domains, because routers in one domain may elect RPs in the other domain, resulting in protocol malfunction or loss of isolation between the domains.

Cisco IOS IP Configuration Guide

IPC-419