Cisco Systems 78-11741-02 manual Enabling IP Multicast over ATM Point-to-Multipoint VCs, IPC-436

Configuring IP Multicast Routing

Configuring IP Multicast over ATM Point-to-Multipoint Virtual Circuits

You must have ATM configured for multipoint signalling. Refer to the “Configuring ATM” chapter in the Cisco IOS Wide-Area Networking Configuration Guide for more information on how to configure ATM for point-to-multipoint signalling.

You also must have IP multicast routing and PIM sparse mode configured. This feature does not work with PIM dense mode.

To configure IP multicast over ATM point-to-multipoint VCs, perform the tasks described in the following sections. The task in the first section is required; the task in the remaining section is optional.

•Enabling IP Multicast over ATM Point-to-Multipoint VCs (Required)

•Limiting the Number of VCs (Optional)

Enabling IP Multicast over ATM Point-to-Multipoint VCs

To enable PIM to open ATM point-to-multipoint VCs for each multicast group that a receiver joins, use the following commands in interface configuration mode on the ATM interface:

	Command	Purpose
Step 1
	Router(config-if)#ip pim multipoint-signalling	Enables IP multicast over ATM point-to-multipoint VCs.
Step 2
	Router(config-if)#atm multipoint-signalling	Enables point-to-multipoint signaling to the ATM
		switch.

The atm multipoint-signalinginterface configuration command is required so that static map multipoint VCs can be opened. The router uses existing static map entries that include the broadcast keyword to establish multipoint calls. You must have the map list to act like a static ARP table.

Use the show ip pim vc EXEC command to display ATM VC status information for multipoint VCs opened by PIM.

See the “IP Multicast over ATM Point-to-Multipoint VC Example” section later in this chapter for an example of how to enable IP multicast over ATM point-to-multipoint VCs.

Limiting the Number of VCs

By default, PIM can open a maximum of 200 VCs. When the router reaches this number, it deletes inactive VCs so it can open VCs for new groups that might have activity. To change the maximum number of VCs that PIM can open, use the following command in interface configuration mode:

Command	Purpose
Router(config-if)# ip pim vc-countnumber	Changes the maximum number of VCs that PIM can open.

Cisco IOS IP Configuration Guide

IPC-436