Load Switching-Stdma Hub; Hub Switching Parameters; Figure B-1 Hub Load Switching Page - Comtech EF Data Vipersat SLM-5650A User Manual

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.
• Load Switching – This is a type of Automatic Switching that is based on
• STDMA Slot Capacity – This is a threshold value. When the amount of
• STDMA Switch Delay – This is a built-in latency that forces a Remote to
A p p e n d i x B - A u t o m a t i c S w i t c h i n g
Figure B-1
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.
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.
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.
Hub Load Switching Page
L o a d S w i t c h in g
B-7