Comtech EF Data CDM-570A - Manual (Page 329)

CDM-570A/570AL Satellite Modem with Optional Packet Processor MN-CDM570A
Optional Packet Processor - Serial/Telnet CLI Operation Revision 2
9–33
Selection Hot Key Description
Modem as Server:
IGMP query period
Q Set a value, in seconds, from 1 to 600. This defines the time interval in which
the IGMP protocol requests that a server periodically publish to users on the
LAN the Multicast IP Addresses that it can service. The IGMP query period
defines the time interval between each of these queries for membership.
Modem as Server:
IGMP max. response
time
R Set a value, in seconds, from 1 to 598. This defines the time interval for the
IGMP max response time that the Packet Processor should wait before it
assumes that no parties are interested in the content published via an IGMP
query. The max response time that is accepted by the Packet Processor
should a value that is less than the Query period minus 1.
Modem as Server:
Number of missed
responses before
leaving IGMP group
M Set a value, from 1 to 30. This defines the number of membership queries that
go unanswered from LAN clients before the Ethernet Interface no longer
forwards data for that IGMP group.
For example, for an Packet Processor that has the IGMP query period set to
60 seconds and the number of missed responses is set to 3: If a client joins an
IGMP group, then the service to that group will not be discontinued until no
clients respond to a query from the Packet Processor for a period of 60*3 =
180 seconds.
Modem as Client:
Recognize IGMP
queries
C Toggle to set as ‘Y’ (Yes) or ‘N’ (No):
• If you toggle YES, the Packet Processor responds to an IGMP query by
requesting to join a Multicast Group published by the server that is
defined in the Packet Processor’s route table.
• If you toggle NO, the Packet Processor does not respond to IGMP
queries from a server. In this type of configuration, you may configure the
Packet Processor to unconditionally request to join an IGMP group at an
interval specified by the “Unsolicited Report Interval” option from the
Transmitter IGMP Client Configuration Page.
Modem as Client:
Router Alert Option for
V1 report
A Toggle to set as ‘Y’ (Yes) or ‘N’ (No):
Some Routers may require the definition of a Router Alert Option to recognize
a report from a Client to join a Multicast group. The IP Router Alert Option is
defined in RFC2113 and was introduced by Cisco. While this option is not part
of the IGMP standard, most IGMP V2 implementations contain this option.
However, most implementations of IGMP V1 do not contain this option. This
parameter is defined to prevent possible conflicts in networks in which a Cisco
Router is configured as an IGMP V1 server.
• When you toggle YES, the Packet Processor generates IGMP reports to
join Multicast groups as specifically required by some Cisco Router
configurations.
• When you toggle NO, the Packet Processor generates IGMP reports to
join Multicast groups as defined and implemented by most IGMP servers.