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Command Reference Guide
ip mcast-stub helper-address <ip address>
Use the ip mcast-stub helper-address command to specify an IP address toward which Internet Group
Management Protocol (IGMP) host reports and leave messages are forwarded. This command is used in IP
multicast stub applications in conjunction with the ip mcast-stub downstream and ip mcast-stub
upstream commands. Use the no form of this command to return to the default setting.
Syntax Description
<ip address>
Default Values
By default, no helper-address is configured.
Command History
Release 7.1
Functional Notes
The helper address is configured globally and applies to all multicast-stub downstream interfaces. The
address specified may be the next upstream hop or any upstream address on the distribution tree for the
multicast source, up to and including the multicast source. The router selects, from the list of multicast-stub
upstream interfaces, the interface on the shortest path to the specified address. The router then proxies,
on the selected upstream interface (using an IGMP host function), any host joins/leaves received on the
downstream interface(s). The router retransmits these reports with addresses set as if the report originated
from the selected upstream interface.
For example, if the router receives multiple joins for a group, it will not send any extra joins out the
upstream interface. Also, if it receives a leave, it will not send a leave until it is certain that there are no
more subscribers on any downstream interface.
Usage Examples
The following example specifies 172.45.6.99 as the helper address:
(config)#ip mcast-stub helper-address 172.45.6.99
60000CRG0-35E
Specifies the address to which the IGMP host reports and leave messages
are forwarded. IP addresses should be expressed in dotted decimal
notation (for example, 10.10.10.1).
Command was introduced.
Copyright © 2012 ADTRAN, Inc.
Global Configuration Mode Command Set
1042
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