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DEFLATE compression:
When this parameter is set to “Off”, DEFLATE compression is disabled on this PPP instance. When
set to “On”, DEFLATE compression is enabled and data compression is applied to the data being
carried. The effectiveness of data compression will vary with the type of data but a typical ratio
achieved for a mix of data, for instance Web pages, spread sheets, databases, text
fi
les, GIFs, etc.
would be between 2 and 3:1. This has the effect of increasing the connection throughput. If the data
is traversing a network where charges are based on the amount of data passed (such as many
GPRS networks), it may also offer signi
fi
cant cost savings. Note however that if the data is already
compressed, such as .zip or .jpg
fi
les, then the system will detect that the data cannot be compressed
further and send it un-compressed.
MPPE encryption:
When this parameter is set to “On”, the PPP instance will attempt to negotiate MPPE (Microsoft
Point to Point Encryption) with the remote peer. It the remote is unable or unprepared to negotiate
MPPE, negotiations will fail. When negotiated, the PPP will encrypt the PPP frames as per the MPPE
standard.
MPPE key size:
This parameter indicates the desired encryption key length to use with MPPE. Valid values for
the
mppebits
parameter are “Auto”, “40”, “56” and “128”. “Auto” indicates that the unit will accept
whatever the remote suggests. For the other values, the remote must accept and request the keysize
speci
fi
ed, else the PPP negotiations will fail.
Note:
With MPPE is that there is no pre-shared keys to set up or keys to set up at all. The encryption
keys are determined by the PPP links themselves on start-up. Therefore, MPPE does not provide
authentication, and only encrypts the data sent on the PPP link.
Time band:
This parameter speci
fi
es the Time Band number to use for this PPP instance (see
Confi gure
>
Time
Bands
>
Time Band n
).
Log event up-time (mins):
The unit logs the amount of time that a PPP instance remains connected during each 24-hour period
(continuously or otherwise). This parameter may be used to specify the length of time in minutes that
the instance may remain connected before the unit generates an eventlog entry.
Max up-time/day (mins):
This parameter may be used to set the maximum amount of time in minutes that this PPP instance
may remain connected during each 24-hour period. When set to 0 there is no maximum time limit.
Local IP address:
This is the IP address of the unit. When making outgoing PPP connections, this
fi
eld is generally left
blank, and the remote end of the connection will supply the IP address. If receiving incoming calls, set
this
fi
eld to the desired IP address for the unit.
Remote IP address pool minimum:
PPP has a list of IP addresses to supply to incoming connections. This is the
fi
rst address supplied to
the incoming caller. The
Request IPCP remote address option
parameter on the
Confi gure
>
PPP
>
PPP n
>
Advanced
page should also be set. This parameter may require alteration if the default
value “10.10.10.0” does not suit the remote network con
fi
guration.
