Comtech EF Data CDM-570/570L Vipersat - Manual (Page 75)

Chapter 3 - Using the Command Line Interface (CLI) 3-39
Vipersat Configuration
between 200 and 500 msecs. For higher traffic priority, a lower latency is
desired. Voice traffic, for example, would call for a setting of 200 msecs to
minimize latency effects.
Valid range is 200 to 5000 msecs.
Enable WAN SAR
Packet Segmentation and Reassembly (SAR) can be enabled for QoS. With this
feature, packets are made smaller to speed them through the network and to
satisfy specified packet size restrictions for a given path.
SAR is an adaptive process; it will trigger only if the packet latency exceeds the
threshold value (default is 20 msec). Latency value is calculated based on the
satellite transmission bandwidth. The minimum segment size is limited to 480
bytes—excluding satellite HDLC header information—in order to avoid satel-
lite overhead and consumption of CPU cycles.
Enter R at the prompt in figure 3-42 to toggle between Enabled/Disabled.
Enable QoS Switch Detection Feature
Once QoS has been enabled and configured as described above, the last step in
implementing QoS switching is to Enable the QoS Switch Detection feature.
Entering Q at the command prompt in figure 3-41 toggles the QoS Switch
Detection feature between Enabled and Disabled.
Load Switching
One of the four automatic switching functions that the Vipersat CDM-570/570L
is able to perform is Load Switching. The system will detect variations in data
rate and can be configured to switch from STDMA to SCPC based on band-
width requirements.
The initial switch for a Remote CDM-570/570L from STDMA mode to SCPC
mode is determined by the Hub Burst Controller. Once the Remote is switched
into SCPC, any requests to meet additional switching requirments within SCPC
(Step Up or Step Down) are made by the Remote modem.
The Load Switching command on the Auto Switching menu is a toggle that
Enables and Disables Load Switching on the target CDM-570/570L. Entering
B at the command prompt will toggle between these two states.
Note: Load switching must be Enabled for any CDM-570/570L that will experi-
ence changing load conditions in order for the VMS to dynamically opti-
mize network performance on these circuits.
Application switching by the VMS, such as for Voice and/or Video, is not
NOTE