22
IGMP
IGMP relay/proxy specification and environment:
Support IGMP relay/proxy function for ADSL modem, and base on the
following requirement and case:
•
On CO side, there must be at least one IGMP querier (router) present.
IGMP qureier will send IGMP query packet. The ADSL modem is
responsible to relay these IGMP query to Ethernet.
•
End-user multicast application device send IGMP report while receiving
IGMP query or being activated by user, the ADSL mode should be
responsible to proxy (that is, change source IP to ADSL modem’s WAN IP)
the IGMP report to ADSL WAN side, including all PVCs. The same case is
for IGMP leave packet.
•
Not necessary to relay multicast routing between two ADSL PVCs or two
interfaces in LAN side.
•
Special purpose multicast packet (such as RIP 2 packet) should run without
interference.
Before the IGMP mode is enabled, please go to the
Miscellaneous
Configuration
page to enable the IGMP proxy. Otherwise, the IGMP selection
will not be valid. You may download the free software to test IGMP from
http://manimac.itd.nrl.navy.mil/MGEN/
The table below is the compendious description of packet process.
Rx Entity
Packet Class
TTL
Action
IGMP query
1
Relay to Ethernet
IGMP report
1
Ignore
IGMP leave
1
Ignore
ADSL
General Multicast IP
-
Relay it to Ethernet
IGMP query
1
Ignore
IGMP report
1
Relay to all ADSL PVCs
IGMP leave
1
Relay to all ADSL PVCs
Ethernet
General Multicast IP
-
Ignore
