Quality Of Service - Comtech EF Data CDM-570L Installation And Operation Manual

CDM-570/570L Satellite Modem with Optional IP Module
IP Module Ethernet Interface Overview
15.4.4

Quality of Service

Quality of Service (QoS) is an optional feature of the IP Module. The user may select one
of three modes of QoS operation:
•
Mode 1 – QoS Rules based on Maximum Bandwidth and Priority
•
Mode 2 – QoS Rules based on Minimum and Maximum Bandwidth
•
Mode 3 – DiffServ
QoS Segmentation and Reassembly (SAR) - Packet Segmentation and Reassembly
(SAR) is enabled automatically while QoS is enabled. However, SAR is an adaptive
process; it will trigger only if the packet latency exceeds the threshold value (default to
20 msec). Latency value is calculated based on the satellite transmission bandwidth.
There is no minimum segment size. However if the last segment is less than 16 bytes,
then it will be appended to the previous segment excluding satellite HDLC header in
order to avoid satellite overhead and consumption of CPU cycles.
Algorithm Payload size
ADLC 1472
ADLC 1000
ADLC 500
ADLC 100
ADLC 1472
ADLC 1000
ADLC 500
ADLC 100
LZS 1472
LZS 1000
LZS 500
LZS 100
LZS 1472
LZS 1000
LZS 500
LZS 100
15–8
File Set Ratio
Calgary 1.76
Calgary 1.76
Calgary 1.77
Calgary 2.09
Canterbury 1.71
Canterbury 1.72
Canterbury 1.74
Canterbury 2.04
Calgary 1.66
Calgary 1.66
Calgary 1.68
Calgary 1.97
Canterbury 1.61
Canterbury 1.62
Canterbury 1.63
Canterbury 1.91
Revision 4
MN/CDM570L.IOM