Comtech EF Data SLM-5650A Installation And Operation Manual page 373

E.7.5.6.3 Routing | IGMP
Use this page to facilitate use of Internet Group Management Protocol (IGMP) with configured
multicast routes.
IGMP, when enabled, responds to IGMP queries for the configured multicast routes on the transmit
side and generates IGMP queries on the receive side. If there are no active IGMP receivers on the
LAN, it will stop forwarding the multicast traffic (received from the satellite) to the LAN.
IGMP Parameters
IGMP – Select IGMP as Disabled or Enabled.
Query Interval – Enter a value, in seconds, from 1 to 60. The default value is 1. This is the interval
between general queries sent by the modem. By varying the query interval, a modem administrator
may tune the number of IGMP messages on the subnet; note that larger numbers cause the IGMP
queries to be sent less often.
Response Interval – Enter a value, in seconds, from 1 to 25. The default value is 10. This is the
maximum response time inserted into the periodic general queries. By varying the Response
Interval, a modem administrator may tune the "burstiness" of IGMP messages on the subnet; note
that larger values make the traffic less "bursty" as host responses are spread out over a large
interval.
The number of seconds assigned to the Response Interval must be less than
the number of seconds assigned to the Query Interval.
Last Member Query Interval – Enter a value, in seconds, from 1 to 25. The default value is 10.
This is the maximum response time inserted into group-specific queries that are set in response to
Leave Group messages, and is also amount of time between group-specific query messages. This
value may be tuned to modify the "leave latency" of the network; a reduced value results in reduced
time to detect the loss of the last member of a group.
Appendix E
Figure E-29. Routing | IGMP Page
E–51
SLM-5650A Satellite Modem
Revision 10
MN-SLM-5650A