Comtech EF Data SLM-5650A Vipersat - Manual (Page 55)

Chapter 3 - Using the Web Server Interface (WSI) 3-15
Vipersat Configuration
Figure 3-14 Hub Type Allocation Menu
This selection determines whether available bandwidth will be a static (fixed)
assignment, or whether bandwidth allocation will be dynamic with automatic
switching to dynamically optimize bandwidth utilization.
1 – Fixed
In the Fixed mode, all Remotes have the same data slot size regardless of type
of traffic or load. This mode minimizes the amount of jitter between Remote
transmission times, and is useful for tuning STDMA as well as for troubleshoot-
ing purposes.
2 – Dynamic Slot
In the Dynamic Slot mode, slot size is adjusted each cycle depending on the
activity during the previous cycle. The slot size for each Remote is computed
based on the time (at the current data rate) needed to transmit all the bytes in
queue. If the result is less than the minimum slot size or more than the maxi-
mum slot size, the slot is adjusted accordingly. This mode allows the burst
controller to provide additional slot time in the cycle to Remotes with higher
traffic demands, increasing throughput and alleviating congestion.
3 – Dynamic Cycle
In the Dynamic Cycle mode, available bandwidth is allocated to Remotes
proportionally based on their current bandwidth needs. The bandwidth require-
ments are determined by the number of bytes in queue for each Remote divided
by the total number of bytes in queue for all Remotes, and results in the percent-
age of bandwidth to be allocated for each Remote. This mode provides
improved efficiency of STDMA due to faster cycle times during periods of light
traffic demands, thus providing minimum latency for the current load.
4 – GIR
In the GIR mode, the initial computed slot size value is the same as in the
Dynamic Cycle mode except there is no maximum limit. After all Remotes have