ADTRAN 1000R Series

Command Reference Guide ATM Sub-Interfa c e Config Command Set

ip mcast-stub downstream

Use the ip mcast-stub downstream command to enable multicast forwarding and IGMP (router mode) on

an interface and place it in multicast stub downstream mode. Use the no form of this command to disable.

Syntax Description

No subcommands.

Default Values

By default, this command is disabled.

Applicable Platforms

This command applies to the NetVanta 300, 1000R, 3000, and 4000 Series units.

Command History

Release 7.1 Command was introduced.

Release 8.1 ATM sub-interface was added.

Functional Notes

This command is used in IP multicast stub applications in conjunction with the ip mcast-stub

helper-address and ip mcast-stub upstream commands. Downstrea m interfaces connect to segments

with multicast hosts. Multiple interfaces may be configured in downstream mode; however, interfaces

connecting to the multicast network (upstream) should not be configured in downstream mode. Interfaces

configured as downstream should have the lowest IP address of all IGMP-capable routers on the

connected segment in order to be selected as the designated router and ensure proper forwarding. Refer

to ip mcast-stub help er-address <ip address> on page 434 and ip mcast-stub upstream on pa ge 759 for

more information.

Usage Examples

The following example enables mu lticast forwarding and IGMP on the interface:

(config)#interface atm 1.1

(config-atm 1.1)#ip mcast-stub downstream