Allied Telesis RAPIER I - Manual (Page 56)

56 Internet Group Management Protocol (IGMP) Enhancements Release Note
Software Version 2.8.1
C613-10477-00 REV B
interface. The following table summarises how the IGMP proxy agent
processes each IGMP message type.
The IGMP proxy agent uses the information maintained in the multicast group
membership database to forward multicast data packets received on the
upstream interface to all downstream interfaces that have members of the
multicast group.
Multicast packet forwarding is enabled as long as:
■ a multicast routing protocol is not enabled
■ an interface is configured with IGMP proxy in the upstream direction
■ at least one interface is configured with IGMP proxy in the downstream
direction
To add an IP interface and configure IGMP proxying, use the command:
add ip interface=interface ipaddress={ipadd|dhcp}
[igmpproxy={off|upstream|downstream}] [other-options...]
To configure IGMP proxy on an existing IP interface, use the command:
set ip interface=interface
igmpproxy={off|upstream|downstream}]
IGMP proxy is turned off by default.
IGMP must also be enabled on the router or switch and on the interface for
IGMP proxy to function.
When this message... Is received on this interface... Then the IGMP proxy agent...
Report downstream
• adds the membership subscription to the multicast
group membership database
• forwards the report message on the upstream interface,
if the membership subscription is for a new multicast
group
upstream
• discards the message without processing
Leave downstream • removes the membership subscription from the
multicast group membership database
• forwards the leave message on the upstream interface,
if there are no remaining membership subscriptions for
the multicast group (no other hosts connected to any of
the downstream interfaces have members of the
multicast group)
upstream
• discards the message without processing
Group-specific query downstream
• discards the message without processing
upstream • transmits a report message on the upstream interface,
if the multicast group membership database contains at
least one member of the multicast group attached to a
downstream interface
General query downstream • discards the message without processing
upstream
• transmits a report message on the upstream interface
for each multicast group in the multicast group
membership database with at least one member
attached to a downstream interface