Comtech EF Data CDM-IP 300L - Manual (Page 49)

CDM-IP 300L IP-Centric Satellite Modem Rev. 1
CD/CDMIP300L.IOM
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- Compression statistics are fed back to QoS in order to maximize WAN utilization
while maintaining priority, jitter and latency.
- 1024 simultaneous compression sessions to maximize compression across
multiple distinct traffic flows.
- Compression algorithm not applied to RTP streams because this traffic is already
compressed and would only INCREASE the sat bandwidth if compressed again.
- Additional statistics have been added to the compression statistics menu in order
to provide feedback on the compression efficiency that has been achieved.
ADLC vs LZS compression comparison
Note: These numbers have been generated by using an internally created test program.
This program takes the target benchmark files and splits the files into payload size chunks
and compresses each chunk in a separate invocation of the compression algorithm. This is
important to note because most compression algorithms are applied to the entire file data
set as a single invocation of the compression algorithm which is easier for other types of
compression algorithms (LZS, GZIP in specific). This, of course, does not apply to
streamed packet data across an IP network (ftp transfer, for example).
Algorithm Payload size File Set Ratio
ADLC 1472 Calgary 1.76
ADLC 1000 Calgary 1.76
ADLC 500 Calgary 1.77
ADLC 100 Calgary 2.09
ADLC 1472 Canterbury 1.71
ADLC 1000 Canterbury 1.72
ADLC 500 Canterbury 1.74
ADLC 100 Canterbury 2.04
LZS 1472 Calgary 1.66
LZS 1000 Calgary 1.66
LZS 500 Calgary 1.68
LZS 100 Calgary 1.97
LZS 1472 Canterbury 1.61
LZS 1000 Canterbury 1.62
LZS 500 Canterbury 1.63
LZS 100 Canterbury 1.91