Comtech EF Data SLM-5650A Vipersat - Manual (Page 105)

Appendix B - Automatic Switching B-7
Load Switching
Load Switching—STDMA Hub
Before discussing how load switching is determined, it is necessary to explain
the modem/router parameters that control the switch.
Hub Switching Parameters
The screen shown in figure B-1 shows the entries in the Automatic Switching
page at the Hub that are used to control load switching.
Figure B-1 Hub Load Switching Page
• Load Switching – This is a type of Automatic Switching that is based on
the amount of traffic at a Remote. If this feature is not enabled, then no
Remote in this STDMA group will be switched based on load.
• STDMA Slot Capacity – This is a threshold value. When the amount of
outbound traffic at a Remote exceeds this percentage of the current
STDMA slot capacity, a load switch is initiated. It is important to
understand that in most STDMA modes, the amount of bandwidth
allocated to a Remote varies with need and thus from cycle to cycle. Thus
the amount of traffic that constitutes X% will also vary from cycle to
cycle.
Note for Dynamic Cycle mode:
Since Dynamic Cycle mode tends to provide no more bandwidth than is
needed, Remotes will typically appear to be near 100% capacity whenever
they are passing real traffic. Thus, in this mode, if the threshold is set too
low, switches will occur unnecessarily.
• STDMA Switch Delay – This is a built-in latency that forces a Remote to
maintain an average load over some number of seconds after reaching a
switch condition before the switch is actually initiated. This prevents
switches due to momentary traffic bursts.