Load Switching By A Remote; Figure B-2 Auto Switching Menu (Remote - Comtech EF Data Vipersat CDD-562L User Manual

current load, as indicated by the bytes queued during the delay period, multiply-
ing it by the percent allocation and rounding up to the next 16 Kbps.
A key point is that in most of the STDMA modes, the bandwidth allocated to
each Remote is constantly being adjusted to the needs of the network. As long
as the network is running below capacity, most Remotes will get the bandwidth
they need and a switch will not be required. Only when a Remote requires more
bandwidth than is available in STDMA will a switch occur.
In Dynamic Cycle mode, each Remote will always appear to be running at near
100% capacity, even when there is actually excess bandwidth available. This is
because in Dynamic Cycle mode, the Remotes are almost never given more
bandwidth than they need. As a result, the algorithm for this mode uses a maxi-
mum allowed slot size rather than the actual allocated slot size to calculate the
effective data rate. This results in a more accurate estimate of the available
STDMA bandwidth.

Load Switching by a Remote

Once a Remote has been switched from STDMA mode to SCPC mode, it
checks its bandwidth requirements once per second to see if a change is needed.
The menu for controlling the Step Up/Step Down switches are set in the menu
shown in figure B-2.
• Auto Switching - Same as for Hub.
• Load Switching - Same as for Hub.
• SCPC Step Up Threshold - Same as STDMA Slot Capacity at Hub.
A p p e n d i x A u t o m a t i c S w i t c hi n g
B -
Figure B-2
Auto Switching menu (Remote)
L o a d S w i t c h in g
B-7