Igmp Proxying - HP A8800 Configuration Manual

With the IGMP SSM mapping feature configured, when Router A receives an IGMPv1 or IGMPv2 report,
it checks the multicast group address G carried in the message:
If G is not in the SSM group range, Router A cannot provide the SSM service but can provide the
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ASM service.
If G is in the SSM group range but no IGMP SSM mappings that correspond to the multicast group
•
G have been configured on Router A, Router A cannot provide SSM service and drops the message.
If G is in the SSM group range and the IGMP SSM mappings have been configured on Router A for
•
multicast group G, Router A translates the (*, G) information in the IGMP report into (G, INCLUDE,
(S1, S2...)) information based on the configured IGMP SSM mappings and provides SSM service
accordingly.
NOTE:
The IGMP SSM mapping feature does not process IGMPv3 reports.
For more information about the SSM group range, see

IGMP proxying

In a simple tree-shaped topology, it is not necessary to configure complex multicast routing protocols,
such as PIM, on the edge devices. Instead, you can configure IGMP proxying on these devices. With
IGMP proxying configured, the device serves as a proxy for the downstream hosts to send IGMP
messages, maintain group memberships, and implement multicast forwarding based on the
memberships. In this case, each edge device is a host but no longer a PIM neighbor to the upstream
device.
Figure 33 Network diagram
As shown in
• Upstream interface—Also called the "proxy interface". A proxy interface is an interface on which
IGMP proxying is configured. It is in the direction toward the root of the multicast forwarding tree.
An upstream interface acts as a host that is running IGMP. Therefore, it is also called the "host
interface".
Figure 33, the following types of interfaces are defined on an IGMP proxy device:
"Configuring
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PIM."