6100 MPS-B Programming Manual

INTRODUCTION TO 6100 MPS-B
Line Configuration Options
Each of these types of error causes 6100 MPS-B to perform a
predefined sequence of operations in an attempt to recover. For
example, if text is being received and a BCC error is detected,
6100 MPS-B responds to the incoming message with a NAK control
sequence and waits for the message to be retransmitted. Con-
versely, if a NAK control sequence is received when transmitting
a message, 6100 MPS-B resends the message. Recovery operations
such as these are not visible to the application process.
Line Configuration Options
The line configuration options you define in SYSGEN specify parts
of the electrical interface, message formats, resource
utilization, and error-handling strategies for the line. Most of
your choices depend on the features of hardware you will use on
the link: for example, the characteristics of your modems, the
delays built into some terminals, or the expected quality of a
line.
The System Management Manual for NonStop systems describes each
option in detail. The following summary of options emphasizes
how your choices affect the protocol. Section 3 of the CP6100
I/O Process Programming Manual mentions some effects on the
efficiency of the line.
Options Summary
MPSBCONNECTTIMEOUT (1 word) specifies the interval, in 10-ms
units, that the LIU waits for DSR to raise or drop following an
application START or STOP request for a leased line, or a modem
CONTROL Connect or Disconnect request for a switched line. (An
application START or STOP request is not the same as a CMI START
or STOP command.) If DSR doesn’t raise or drop before the
interval expires, MPS-B informs the application and resets DTR.
The value can range from 0 through 32767. The default value is
3000 (30 seconds).
If the value specified for MPSBCONNECTTIMEOUT is zero, MPS-B
waits indefinitely for DSR.
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