R3303-HP HSR6800 Routers IP Multicast Configuration Guide

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• Downstream interface—An interface that is running IGMP and is not in the direction toward the
root of the multicast forwarding tree. A downstream interface acts as a router that is running IGMP.
Therefore, it is also called the "router interface".
A device with IGMP proxying configured maintains a group membership database, which stores the
group memberships on all the downstream interfaces. Each entry comprises the multicast address, filter
mode, and source list. Such an entry is a collection of members in the same multicast group on each
downstream interface.
A proxy device performs host functions on the upstream interface based on the database. It responds to
queries according to the information in the database or sends join/leave messages when the database
changes. On the other hand, the proxy device performs router functions on the downstream interfaces by
participating in the querier election, sending queries, and maintaining memberships based on the
reports.
IGMP support for VPNs
IGMP maintains group memberships on a per-interface base. After receiving an IGMP message on an
interface, IGMP processes the packet within the VPN to which the interface belongs. If IGMP that runs in
a VPN needs to exchange information with another multicast protocol, it passes the information only to
the protocol that runs in this VPN.
Protocols and standards
• RFC 1112, Host Extensions for IP Multicasting
• RFC 2236, Internet Group Management Protocol, Version 2
• RFC 3376, Internet Group Management Protocol, Version 3
• RFC 4605, Internet Group Management Protocol (IGMP)/Multicast Listener Discovery (MLD)-Based
Multicast Forwarding ("IGMP/MLD Proxying")
IGMP configuration task list
For the configuration tasks in this section, the following rules apply:
• The configurations made in IGMP view are effective on all interfaces. The configurations made in
interface view are effective only on the current interface.
• A configuration made in interface view always has priority over the same global configuration in
IGMP view. If you do not make the configuration in interface view, the corresponding global
configuration made in IGMP view applies to the interface.
Complete these tasks to configure IGMP:
Task Remarks
Configuring basic IGMP
functions
Enabling IGMP Required.
Specifying the version of IGMP Optional.
Configuring an interface as a static member interface Optional.
Configuring a multicast group filter Optional.