Browse Prior Art Database

SNA/DS Data Processing End Node Implementation

IP.com Disclosure Number: IPCOM000120535D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 3 page(s) / 142K

Publishing Venue

IBM

Related People

Greenberg, SA: AUTHOR

Abstract

Systems Network Architecture/Distribution Services (SNA/DS) Formats and Protocols -*- describe a store and forward node that provides asynchronous movement of data from one user to one or more other users. Disclosed is a variation of that architecture. This implementation allows an end node to initiate processing based on the data received from the host. The end node must be able to communicate with a variety of hosts, adhere to SNA formats and protocols, and protect the processing taking place at the end node. Although the end node is perceived by the host to be a simple SNA/DS implementation, it is actually two well-defined logical pieces. One module communicates with the host and the other controls the processing. The two modules communicate through a series of flags and return codes.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 43% of the total text.

SNA/DS Data Processing End Node Implementation

      Systems Network Architecture/Distribution Services
(SNA/DS) Formats and Protocols -*- describe a store and forward node
that provides asynchronous movement of data from one user to one or
more other users.  Disclosed is a variation of that architecture.
This implementation allows an end node to initiate processing based
on the data received from the host.  The end node must be able to
communicate with a variety of hosts, adhere to SNA formats and
protocols, and protect the processing taking place at the end node.
Although the end node is perceived by the host to be a simple SNA/DS
implementation, it is actually two well-defined logical pieces.  One
module communicates with the host and the other controls the
processing.  The two modules communicate through a series of flags
and return codes.

      The following modifications to the model described in the
SNA/DS Formats and Protocols are made in order to create the needed
environment:
1.   SNA/DS Formats and Protocols allow the deallocating of the LU
6.2 conversations while a distribution is being received at the end
node from the host.  In order for multiple hosts to be able to
initiate processing at the end node, the deallocation of a
conversation cannot take place without bringing the distribution
being received to some form of logical termination.  To deallocate
abend is to make the remote node available to any other host and
therefore jeopardize any processing that may have been started.  Data
files and information files used for processing could be corrupted if
more than one host had access to the end node at the same time.  In
order to avoid side effects, the distribution must be cleaned up
before a deallocation can be issued.  If the current distribution is
being stored on a disk, it must be erased, all counters must be
reset, and the registry for that host must be updated to TERMINATED.
Any processing that has not completed must be aborted.

      2.   A secondary tracker is needed to follow the distribution
so that the communications module at the end node can know the state
of the processing.  This tracker must function independently from the
registry.  The registry can give a clear indication of the state of
the transmission, but it does not indicate the state of the
processing.  Processing starts when the registry state is IN TRANSIT
and continues after the distribution has been received and has been
marked PURGED in the registry.  A variable must be added to monitor
the state of the processing.  This information is needed for handling
error conditions.  It is also used after a system crash.  The
processing can be re-initiated at the best logical point based on the
secondary tracker.

      3.   The communicating module and the processing module need to
communicate with each other.  If communication problems occur, the
processing needs to be aborted.  SNA/DS does not provide this type of...