This chapter describes commands that configure the Compression Control Protocol (CCP) layer. All of these commands apply to the currently active bundle.
To use CCP you should enable compression at the bundle level. To allow compression to be negotiated you should enable here some of compression protocols.
set ccp accept option ... set ccp deny option ... set ccp enable option ... set ccp disable option ... set ccp yes option ... set ccp no option ... These commands configure various CCP options. Each direction of
traffic (transmit and receive) is independent from the other.
All options default to disable and deny.
The enable and disable commands determine
whether we desire the corresponding option on received data.
The accept and deny commands determine
whether we will allow the peer to request the corresponding option
(which we must enable on our transmitted data).
The yes command is the same as
enable and accept.
The no command is the same as
disable and deny.
The options available at the CCP layer are listed below.
pred1This option enables Predictor-1 (RFC 1978) compression. Predictor-1 compression is much faster then Deflate.
This option requires ng_pred1 Netgraph node type, which is present since FreeBSD 6.2-STABLE of 2007-01-28. If there is no ng_pred1 in system, this algorithm is supported in user-level, but will consume more CPU power.
The default is disable.
deflateThis option enables Deflate (RFC 1979) compression. Deflate compression usually gives better compression ratio then Predictor-1.
This option requires ng_deflate Netgraph node type, which is present since FreeBSD 6.2-STABLE of 2007-01-28.
The default is disable.
mppcThis option enables MPPC compression/encryption subprotocol. For details see the MPPC protocol chapter.
The default is disable.