Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 115)

Chapter 3 - VMS Configuration 3-15
MN/22156, rev 12 Vipersat Manager Configuration
10. The Communications timer values set timeouts for command messages.
The Retry Timeout is the wait between messages which works in conjunc-
tion with Retry Count. A retry count of 3 and a timeout of 5 seconds would
set the message failure at a total timeout of 15 seconds with 3 attempts to
command the modem.
If communication latencies are greater than default settings (command
communication failures), increase the Retry Timeout value.
11. The Status Update Messages (SUMs) values set the dual timeouts and
debounce for Remotes that are either in SCPC mode or ECM.
• The SCPC Timeout parameter is the time interval between the sending
of SUMs to the VMS by Remotes that are in SCPC mode.
• The ECM Timeout is the time interval between the sending of SUMs
to the VMS by Remotes that are in Entry Channel Mode.
• The Debounce is a counter setting for the number of consecutive time
intervals that can pass without the VMS receiving a SUM for a
particular Remote unit before a switch failure occurs for that Remote.
Generally, the SCPC Timeout is set to a relatively short interval to provide
timely responses to switch requests, such as due to variations in load for
Load Switching applications.
For networks that support large numbers of Remotes that are often operating
in ECM—such as those in “Wait” mode, for example—, a longer interval
setting for ECM Timeout will reduce contention for shared bandwidth usage.
12. The Heartbeat timer settings include the Interval, Timeout and Debounce
values for Hub device redundancy messaging.
• The Interval parameter updates the modem to send it’s heartbeat
message to the VMS at the set rate.
• The Timeout is how long the VMS will wait before determining
communications failure and commanding a device redundancy
switchover.
• The Debounce is a counter setting for the number of consecutive
alarmed messages the VMS will receive from a particular Hub unit
before a redundancy switch is triggered. This parameter setting is useful
for reducing or eliminating unnecessary redundancy triggers due to
spurious alarms.
13. The Announcement Period is the interval at which the VMS will multicast
its management IP address to all listening modems within the network. This
ensures, for example, that remotes that are not online during a redundancy
switch will pick up the new managing address when they come back online.