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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 device serve as an IGMP proxy.
Configuration guidelines
•
Each device can have only one interface serving as the proxy interface. In scenarios with
multiple instances, IGMP proxying is configured on only one interface per instance.
•
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 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:
Step 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
Typically, to avoid duplicate multicast flows, only queriers can forward multicast traffic. On IGMP
proxy devices, a downstream interface must be a querier in order to forward multicast traffic to
downstream hosts. If the interface has failed in the querier election, you must manually enable
multicast forwarding on this interface.
On a multi-access network with more than one IGMP proxy device, you cannot enable multicast
forwarding on any other non-querier downstream interface after one of the downstream interfaces of
these IGMP proxy devices 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
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Enable multicast forwarding on
a non-querier downstream
interface.
igmp proxying forwarding
Disabled by default.
