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Mapping Failure (ERROR) Messages From Certain Intelligent Modems to IBM System/370 Csw Error Sense Codes

IP.com Disclosure Number: IPCOM000100017D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 4 page(s) / 164K

Publishing Venue

IBM

Related People

Davis, GW: AUTHOR [+3]

Abstract

Disclosed is a method for System/370 ICA autocall that eliminates an AUTOCALL UNIT (CCITT V.25) and also takes advantage of CALL STATUS INDICATION messages provided by Intelligent Modems (such as described by CCITT V.25bis) for analysis of Telecommunication Line errors. This permits the line analysis information to be presented to IBM System/ 370 Communications Control Software, such as VTAM, to perform appropriate pre-programmed recovery and retry actions based upon the type of error. It also permits the line analysis information to be presented to IBM System/370 Network Management Software, such as Netview, to perform appropriate network management and problem analysis based upon the information extracted from CALL STATUS INFORMATION messages provided by Intelligent Modems.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 42% of the total text.

Mapping Failure (ERROR) Messages From Certain Intelligent Modems to IBM System/370 Csw Error Sense Codes

       Disclosed is a method for System/370 ICA autocall that
eliminates an AUTOCALL UNIT (CCITT V.25) and also takes advantage of
CALL STATUS INDICATION messages provided by Intelligent Modems (such
as described by CCITT V.25bis) for analysis of Telecommunication Line
errors.  This permits the line analysis information to be presented
to IBM System/ 370 Communications Control Software, such as VTAM, to
perform appropriate pre-programmed recovery and retry actions based
upon the type of error.  It also permits the line analysis
information to be presented to IBM System/370 Network Management
Software, such as Netview, to perform appropriate network management
and problem analysis based upon the information extracted from CALL
STATUS INFORMATION messages provided by Intelligent Modems.

      Existing Communications Software for IBM System/370 Processing
Systems, such as VTAM, performs the function of establishing a
connection through a modem and Autocall Unit (CCITT V.25) to a
switched telecommunications network.  When establishing a connection,
commands are issued to the System/370 Telecommunications Subsystem to
dial a supplied telephone number and to begin communications with a
remote modem (usually attached to another processing system).  The
System/370 Telecommunications Subsystem monitors control lines
attached to the Autocall Unit (PRESENT NEXT DIGIT, DATA LINE
OCCUPIED, ABANDON CALL AND RETRY, DISTANT STATION CONNECTED) and
modem (DATA SET READY, CLEAR TO SEND, AND RECEIVE LINE SIGNAL DETECT)
to determine the status of the connection.  Any unexpected control
line states, or changes in state, are reported to the Communications
Software, which initiates any error recovery or command retry that
would be required.

      Fig. 1 is a block diagram of the components required for
existing V.25 autocall systems.

      On existing 370 Systems, the actions taken by the
Communications Software are limited to information from the Autocall
Unit and modem control lines plus expected timings and states that
are indicative of the type of error condition encountered.  The
resulting action may therefore be inappropriate for the error and
ultimately require unnecessary operator intervention or a costly
service call, in addition to a loss of valuable system time.

      This new method eliminates the Autocall Unit and replaces the
Dumb Modem with an Intelligent Modem.  An enhanced form of the
information previously gathered form the Autocall Unit is then
provided by more comprehensive CALL STATUS INDICATION messages from
the Intelligent Modem, such as an IBM 5853, and reported to the
system Communications Software.  More accurate assessments of the
communications line status is then possible, resulting in better
system performance and reliability.

      Fig. 2 is a block diagram of the components required for this
m...