Digi TransPort User Manual page 170

This option removes the inhibit state from the interface and uses the normal idle time
associated with it to control when it deactivates.
Bring up interface and use idle period of s seconds
This option causes the interface to become activated but rather than using the idle timer
associated with the interface, specify the idle timeout.
Inhibit other PPP interface if this PPP interface is disconnected but operational
When checked, this checkbox enables this PPP instance to inhibit other PPP instances if it is
operational but not currently active.
Attempt to negotiate DEFLATE compression on this interface
When checked, this checkbox causes the router to compress the data transferred over this
link. When unchecked, compression is disabled. The effectiveness of data compression will
vary with the type of data but a typical ratio achieved for a mix of data such as web pages,
spreadsheets, databases, text files and (uncompressed) image files would be between 2:1 and
3:1. Using compression has the effect of increasing the effective throughput. Using
compression may offer cost savings on a network where charges are based upon the amount
of data transferred (such as W-WAN networks). If the data is already compressed (such as .zip
files or JPEG images) then the compression algorithm will detect this and send the data
without attempting further compression.
Attempt to negotiate MPPE encryption on this interface
When checked, this checkbox causes the router to attempt to negotiate Microsoft Point-to-
Point Encryption (MPPE) with the remote peer. If the remote peer is unable to negotiate MPPE,
negotiations will fail. When negotiated, the PPP instance will encrypt the PPP frames as per the
MPPE specification.
MPPE key size
The values in this drop-down list select the length (in bits) of the encryption key. The options
are:
• Auto
• 40 bits
• 56 bits
Digi TransPort User Guide
Advanced Interfaces parameters
170