Browse Prior Art Database

Single System Image and Load Balancing with Parallel Session Support for Network Access to a Loosely-Coupled Processor Complex

IP.com Disclosure Number: IPCOM000116516D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 128K

Publishing Venue

IBM

Related People

Hall, JL: AUTHOR [+3]

Abstract

In environments where an application is supported across multiple loosely-coupled processors, the user generally does not care which specific instance of the application they are bound to when multiple instances exist. Multiple instances of the application are necessary to provide availability or throughput requirements. This invention allows multiple real instances of an application to represent simultaneously the generic application function, while providing load balancing for throughput. In addition, unlike existing generic name functions, this invention supports parallel name protocol requirements.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 47% of the total text.

Single System Image and Load Balancing with Parallel Session Support
for Network Access to a Loosely-Coupled Processor Complex

      In environments where an application is supported across
multiple loosely-coupled processors, the user generally does not care
which specific instance of the application they are bound to when
multiple instances exist.  Multiple instances of the application are
necessary to provide availability or throughput requirements.  This
invention allows multiple real instances of an application to
represent simultaneously the generic application function, while
providing load balancing for throughput.  In addition, unlike
existing generic name functions, this invention supports parallel
name protocol requirements.

      Name servers allow a generic name to represent multiple
instances of the application.  This allows an instance of the
application to be started on different processors, thereby insuring
that the failure of any one processor will not be of critical
importance.  Current schemes have the drawback of either:
  o  Not supporting load balancing, i.e., all requests to the generic
      application are bound to one available instance.  Therefore,
the
      extra processing power from having multiple computers available
      is not taken advantage of, and there is no gain in throughput
or
  o  Parallel sessions are not supported, i.e., parallel sessions to
      the generic name are not guaranteed to become bound to the same
      instance of the application.  If parallel sessions are split
      between two or more instances, it will break some existing LU
      protocols (ex. LU6.2).

      This invention allows an LU using a protocol that allows
parallel sessions (ex. LU6.2) to initiate the session using a
"generic" name, but in fact obtain a session with an application with
a different "real" name.  This function differs from existing name
servers in that all parallel sessions from the same initiating LU to
the "generic" name are guaranteed to be set up with the same real
application.

      In the Figure, the user LU wishes to be bound to the
application APPL, but does not need to know, or want to be involved
in, the selection of the actual real instance that APPL represents.
When each real instance of the application starts up, it indicates
not only its real name, but the name of the generic set of which it
wishes to be a member.  In the Figure, APPL1, APPL2 and APPL3 will
all register themselves as being members of the generic resource
APPL.  Using SNA flows (subarea or APPN) the request for the generic
resource from the User LU arrives at either of the 2 nodes designated
as Network Nodes (NN).  These nodes function as the name servers.

      The key function created by generic resources uses the ability
of a loosely coupled complex to store data known to one host in the
complex in storage accessible to all hosts in the complex.  The...