Comtech EF Data SLM-5650A Vipersat Parameter Editor - Manual (Page 25)

Chapter 2 - Using Parameter Editor 2-9
Vipersat
For example, the SLM-5650A shown in figure 2-5 is operating as a Hub, with
the allocation method set for Entry Channel Mode. Some of the parameter fields
may be unavailable for input (grayed out), depending upon the method that is
selected. The screen shown in figure 2-6 shows an SLM-5650A being used as a
Remote, with only a subset of the fields that appear for a Hub unit.
If the SLM-5650A is being used as an Expansion unit — for either a Hub or a
Remote — no STDMA menu options are available since it is only used as an
SCPC demod.
Enable STDMA
In order to utilize the Vipersat STDMA feature (burst mode) in this modem, the
Enable STDMA check box must be selected.
For a Hub STDMA Burst Controller or a Remote STDMA modem, this feature
must be Enabled. For a private point-to-point SCPC modem, Hub or Remote,
this feature must be Disabled.
Allocation Method
Active for Hub modems only.
When the target SLM-5650A is being used as a Hub, it has five modes of opera-
tion which define the method the Burst Controller uses to allocate slot timing.
Figure 2-7 Burst Slot Allocation Method
Select an STDMA mode of operation for the SLM-5650A from the Allocation
Method drop-down menu shown in figure 2-7.
• Fixed - All Remotes get the same size slot, regardless of each Remote’s
activity.
• Dynamic Slot - Slot size is adjusted each cycle depending on activity
during the previous cycle.
• Dynamic Cycle - A Dynamic Cycle allows changing the cycle time—and
corresponding latency—as loads change, always providing minimum
latency for the current traffic load.
• GIR - Guaranteed Information Rate allows assigning guaranteed data
rates for each Remote in the group within the burst channel.