Browse Prior Art Database

Single System Image and Load Balancing for Network Access to a Loosely Coupled Complex

IP.com Disclosure Number: IPCOM000107435D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 186K

Publishing Venue

IBM

Related People

Menditto, LF: AUTHOR [+3]

Abstract

In environments where an application is supported across multiple loosely coupled processors, the user generally does not care which instance of the application processes his requests. The user prefers that the processor complex and/or the network route his request such that it is processed in the most expeditious manner. In today's SNA network, the end user must request a session with a specific application instance (and, therefore, a specific processor). If that instance of the application is unavailable, the request fails and is not re-routed to a working processor. (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 36% of the total text.

Single System Image and Load Balancing for Network Access to a Loosely Coupled Complex

       In environments where an application is supported across
multiple loosely coupled processors, the user generally does not care
which instance of the application processes his requests.  The user
prefers that the processor complex and/or the network route his
request such that it is processed in the most expeditious manner.  In
today's SNA network, the end user must request a session with a
specific application instance (and, therefore, a specific processor).
If that instance of the application is unavailable, the request fails
and is not re-routed to a working processor.

                            (Image Omitted)

      We solve this problem by intercepting such session requests in
the Logon Manager and calculating the application server which is
best fit to service the request. The session request is then
re-routed to this server.

      In order to satisfy requirements for continuous system
availability and the increased demands on processing power generated
by today's business applications, a number of businesses are
resorting to clustering of their computers in such a way that any of
a number of computers can service the requested work.  Multiple
instances of applications are started within the cluster such that if
one computer is unavailable, the application can be reached via
another computer. Traditional computer networking paradigms, however,
require the end- user to request network connections (hereafter
referred to as sessions) with specific computers and, therefore,
cannot support general session request to be serviced by ANY computer
in a cluster.  As a result, while achieving an aggregate increase in
processing power and availability, the end-user loses the simplicity
offered by single computer systems.  The end-user is forced to have
awareness (knowledge) of the clustering of computers (hereafter
referred to as a complex) and, if he is to obtain optimal
performance, he needs to be aware of network topology and current
load on each computer.  Lacking this knowledge, he may choose a
computer which is overloaded or which requires his session to
traverse a suboptimal path. The invention described herein extends
the usability attributes of a single system (single system image) to
the end-user while maintaining and enhancing the availability and
performance characteristics of computer complexes.

      Examples of industries using computer complexes in this way are
the airline reservations and financial industries. Those using IBM
products, for example, would be using IBM's:
Transaction Processing Facility (TPF)
      A transaction processing system designed to service short
information requests and containing its own integrated operating
system and network access method.
Virtual Telecommunications Access Method (VTAM*)
      A network access method (not to be confused with the one...