Avaya Configuring Data Compression Services Manuel d'utilisateur télécharger pdf (Page 24)

Configuring Data Compression Services

1-6

CCP Negotiations

CCP allows the two ends of a PPP connection to negotiate whether to use data

compression, and if so, which algorithm to use. Our implementation of

compression uses only the LZ-77 algorithm.

In the example shown in Figure 1-1, negotiations begin when PPP establishes a

link. CCP uses the same conﬁguration and network control protocol negotiations

that the Link Control Protocol (LCP) uses. For a detailed explanation of LCP

negotiations, see “Establishing the PPP Link” in

Conﬁguring PPP Services.

WCP Negotiations

Frame Relay and X.25 use WCP to negotiate whether to use data compression,

and which algorithm to use. As with PPP, if one side of a link requests an

algorithm the other side does not support, trafﬁc continues, but in uncompressed

form.

Each side of a link running data compression has a compressor, a decompressor, a

compression history, and a buffer. When you conﬁgure compression, you can edit

WCP parameters for compression mode, history size, and buffer size to optimize

compression performance on your network.

Data Transmission

Frame Relay and X.25 data transmission using compression begins when WCP

negotiations are complete. For PPP, Network Control Protocol (NCP) negotiations

and WCP negotiations occur simultaneously. When PPP NCP and WCP

negotiations are complete, data transmission using compression begins.

Note:

If one side of a link requests an algorithm that the other side does not

support, trafﬁc over the link continues, but in uncompressed form.

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Avaya Configuring Data Compression Services Manuel d'utilisateur Page 24