Comtech EF Data CDM-570/L Vipersat Parameter Editor - Manual (Page 52)

Vipersat
2-36 CDM-570/L, CDD-56X Parameter Editor User Guide
The value entered in the Stats Collection field defines the period of time, in
seconds, over which the CDM-570/570L will collect statistics. A longer time
will average out peak conditions, a shorter time will shorten VMS reaction time
to changing network conditions.
Burst Map Rate
Active for Hub in Fixed or Dynamic Slot only.
The Burst Map Rate field specifies the number of spin cycles that will occur
prior to each broadcast of the burst map by the burst controller to the remotes.
One cycle is the amount of time it takes for all remotes in a group to burst on the
common channel. The burst map provides each remote with its allocated band-
width and position in the cycle.
For Dynamic Cycle, GIR, and Entry Channel modes, the number of cycles is
automatically set to one in order to ensure optimum performance for these Hub
types.
Preamble
Active for Hub modems only.
The Preamble field specifies the preamble duration, in milliseconds, for the
remotes in the group. This is the period between when the remote begins to
transmit (sends an ACK) to the Hub and when the first data packet is sent. This
allows time for signal lock to occur before data is sent, thus preventing data
loss.
Higher data rates allow for a shorter preamble, since it is easier to achieve signal
lock.
Tip: Refer to the Viper Calculator for determining preamble length values to
enter at the command prompt. For a copy of the latest Viper Calculator,
contact your Comtech Vipersat Networks representative.
Note: When the Low Data Rate Fast Acquisition feature is enabled, the Pream-
ble length is set automatically for the unit.
Guard Band
Active for Hub modems only.
The Guard Band field defines the length of the guardband, in milliseconds, for
the remotes in the group. The Slot Guardband is the amount of time between the
point when one remote completes transmitting data and the point when the next
NOTE