HP 6125G - Enabling IGMP Proxying; Configuring Multicast Forwarding on a Downstream Interface

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• Configure any unicast routing protocol so that all devices in the domain are interoperable at the
network layer.
• Enable IP multicast routing.
Enabling IGMP proxying
You can enable IGMP proxying on the interface in the direction toward the root of the multicast
forwarding tree to make the switch serve as an IGMP proxy.
Configuration guidelines
• Each switch can have only one interface serving as the proxy interface..
• You cannot enable IGMP on an interface with IGMP proxying enabled. Moreover, only the igmp
require-router-alert, igmp send-router-alert, and igmp version commands can take effect on such
an interface.
• You cannot enable other multicast routing protocols (such as PIM-DM or PIM-SM) on an interface
with IGMP proxying enabled, or vice versa. However, the source-lifetime, source-policy, and
ssm-policy commands configured in PIM view can still take effect. In addition, in IGMPv1, the
designated router (DR) is elected by the working multicast routing protocol (such as PIM) to serve as
the IGMP querier. Therefore, a downstream interface running IGMPv1 cannot be elected as the DR
and thus cannot serve as the IGMP querier.
• You cannot enable IGMP proxying on a VLAN interface with IGMP snooping enabled, or vice
versa.
Configuration procedure
To enable IGMP proxying:
Ste
p
Command
Remarks
1. Enter system view.
system-view N/A
2. Enter interface view.
interface interface-type interface-number
N/A
3. Enable the IGMP
proxying feature.
igmp proxying enable Disabled by default
Configuring multicast forwarding on a downstream interface
Only queriers can forward multicast traffic but non-queriers have no multicast forwarding capabilities.
This design helps avoid duplicate multicast flows. It is the same on IGMP proxy switches. Only the
downstream interfaces acting as a querier can forward multicast traffic to downstream hosts.
However, when a downstream interface of a proxy switch fails to win the querier election, you must
enable multicast forwarding on this interface.
On a multi-access network with more than one IGMP proxy switch, you cannot enable multicast
forwarding on any other non-querier downstream interface after one of the downstream interfaces of
these IGMP proxy switches has been elected as the querier. Otherwise, duplicate multicast flows might
be received on the multi-access network.
To enable multicast forwarding on a downstream interface: