Avaya Configuring Data Compression Services Manuel d'utilisateur télécharger pdf (Page 21)

Data Compression Overview

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Data Compression Performance

The goals in using data compression are to achieve a high

compression ratio

while

maximizing

throughput.

Compression ratio is the size of uncompressed data

compared to the size of the same data after it has been compressed. Throughput

refers to the speed of transmitting data.

The compression ratio varies according to the effectiveness of the compression

algorithm, but also according to the characteristics of the data you are

transmitting: data that includes a lot of redundant strings compresses at a high

ratio.

Throughput, or network response time, varies with the number of elements in that

network that the data must traverse, including the compression/decompression

process.

Software Compression

Bay Networks software-based data compression is most effective for sites that

have WAN connections at relatively low speeds such as 56/64 KB, where you

want to achieve data compression at low cost, and with minimal memory

requirements. It supports up to 512 Kb/s on the FRE-040. For networks operating

at faster speeds, you must use hardware compression.

Hardware Compression

Bay Networks hardware-based compression works with Frame Relay and Point-

to-Point Protocol (PPP) networks. It best serves sites that support T-1/E-1 lines,

which often concentrate many lower-speed remote connections. Our hardware

compression facility operates at high speeds, and also supports high-density WAN

connections. Use hardware compression when you want to achieve high

compression ratios and throughput, and also want to preserve router memory to

perform other functions.

We offer two compression daughterboards.

• AG2104037 — Octal Sync with a 32-context hardware compression

daughterboard

• AG2104038 — Octal Sync with a 128-context hardware compression

daughterboard

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Avaya Configuring Data Compression Services Manuel d'utilisateur Page 21