Payload Compression; Adlc Vs Lzs Compression Comparison - Comtech EF Data CDD-562L Installation And Operation Manual

CDD-562L/564 Demodulator with IP Module
IP Module Ethernet Interface
4.2.3

Payload Compression

Traffic optimization through Payload Compression is another optional feature of the demodulator.
•
FAST feature to upgrade
•
Uses AHA© chip
•
Compression algorithm applied to all data (HDLC header excluded).
•
Compression statistics are fed back to QoS in order to maximize WAN utilization
while maintaining priority, jitter and latency.
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1024 simultaneous compression sessions to maximize compression across multiple
distinct traffic flows.
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Compression algorithm not applied to RTP streams because this traffic is already
compressed and would only INCREASE the satellite bandwidth if compressed again.
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Additional statistics have been added to the compression statistics menu in order to
provide feedback on the compression efficiency that has been achieved.
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Payload Compression is selectable on a per route basis.
4.2.3.1

ADLC vs LZS Compression Comparison

These numbers have been generated 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 (e.g., FTP transfer).
Algorithm
ADLC
ADLC
ADLC
ADLC
ADLC
ADLC
ADLC
ADLC
Payload
File Set
size
1472 Calgary
1000 Calgary
500 Calgary
100 Calgary
1472 Canterbury
1000 Canterbury
500 Canterbury
100 Canterbury
Ratio Algorithm
1.76 LZS
1.76 LZS
1.77 LZS
2.09 LZS
1.71 LZS
1.72 LZS
1.74 LZS
2.04 LZS
4–5
MN/CDD564L.IOM
Payload
File Set
size
1472 Calgary
1000 Calgary
500 Calgary
100 Calgary
1472 Canterbury
1000 Canterbury
500 Canterbury
100 Canterbury
Revision 2
Ratio
1.66
1.66
1.68
1.97
1.61
1.62
1.63
1.91