Load balancing of connections to parallel servers

• US 5,740,371 A
• Filed: 03/18/1996
• Issued: 04/14/1998
• Est. Priority Date: 09/30/1995
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wallis, Graham Derek
• Primary Examiner(s): Bowler, Alyssa H.
• Assistant Examiner(s): JUNEAU, DARRELL SCOTT
• Application Number:
  US08/617,461
• Time in Patent Office: 757 Days
• Field of Search: 395/200.57, 395/200.58, 395/200.59, 395/200.68, 395/200.69, 395/200.71, 395/200.75, 395/412, 395/413, 395/674, 395/675
• US Class Current: 709/229
• CPC Class Codes: G06F 9/4416 Network booting; Remote initial program loading [RIPL]
• CPC Class Codes: G06F 9/452 Remote windowing, e.g. X-Window System, desktop virtualisation protocols for virtual reality H04L67/131
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1038 Load balancing arrangements to avoid a single path through a load balancer

Abstract

A system and method for facilitating compatibility with a prior process used for connecting a user terminal to a selected server in a system having a plurality of servers. The prior process has the server perform a task on behalf of the terminal. The system includes a server determination process for retrieving from storage a table of data identifying the servers, and for determining an address currently associated with each server. Then, a chooser process enables the user to select from the table, one of said servers for connection to the terminal with a connection process, responsive to a signal from the terminal, that initiates a connection of the terminal to the selected server. The plurality of servers in the system includes at least one parallel server comprised of multiple processors. The data in the table identifying the parallel server is a generic identifier, and a process is employed, which preferably uses predetermined dynamic criteria, to periodically associate a specific processor of the parallel server with that generic name. To enable the load to be balanced across the plural processors of the parallel server, the server determination process is adapted to recognize any generic identifier in the table, and to determine the address associated with that generic identifier after a user selection of the parallel server corresponding to that generic identifier has been made.

Claims

1. A system for facilitating connection of a terminal (20) to a server (60, 70, 80) to enable the server to perform a task on behalf of the terminal, there being a plurality of servers which the terminal may connect to, and the system comprising:

server determination means (14) for retrieving from a storage means (90) data identifying the plurality of servers, and for referencing an address conversion means (92,

     94) to determine an address currently associated with each server;

chooser means (16) for providing information about the plurality of servers to the terminal, the terminal being arranged to display this information so as to enable the user to select one of said servers for connection to the terminal; and

connection means (18), responsive to a signal from the terminal indicating a user selection of one of said servers, to initiate connection of the terminal to the selected server;

the system being characterised by;

at least one of the plurality of servers having multiple processors, the data in the storage means (90) identifying that server being a generic identifier for the processors within that server;

the address conversion means (92,

     94) having means (94) for periodically identifying one of the processors of that server based on predetermined criteria, and for updating the information in the address conversion means such that at any instant in time, the address associated with the generic identifier is the address of the identified processor; and

the server determination means (14) being adapted to recognise any generic identifier, and to reference the address conversion means to determine the address associated with that generic identifier after a user selection of the server corresponding to that generic identifier has been made.

2. A system as claimed in claim 1, wherein the chooser means (16) is adapted to identify a user selection of a server represented by a generic identifier, and to respond to such a user selection by instructing the server determination means (14) to reference the address conversion means (92, 94) to determine the address associated with that generic identifier.

3. A system as claimed in claim 2, wherein the server determination means (14) is incorporated within the chooser means (16).

4. A system as claimed in any of claims 1 to 3, wherein, upon retrieval by the server determination means (14) of data identifying the plurality of servers, the chooser means (16) is arranged to contact any of said servers which are not identified by a generic identifier to determine whether they are able to manage a connection with the terminal, but not to contact prior to user selection any server identified by a generic identifier, the information thus displayed on the terminal identifying any servers with generic identifiers, in addition to any other servers which the chooser means (16) has determined are able to manage the connection with the terminal.

5. A system as claimed in claim 1, wherein the generic identifier has a keyword associated with it.

6. A system as claimed in claim 1, wherein the terminal is an X terminal arranged to run the presentation logic for the X Window system.

7. A system as claimed in claim 6, wherein the server determination means (14), chooser means (16) and connection means (18) are provided on an XDMCP host computer (10) arranged to run the XDM program.

8. A method of facilitating connection of a terminal (20) to a server (60, 70, 80) to enable the server to perform a task on behalf of the terminal, there being a plurality of servers which the terminal may connect to, and the method comprising the steps of:

a) retrieving from a storage means (90) data identifying the plurality of servers, and referencing an address conversion means (92,

     94) to determine an address currently associated with each server;

b) employing a chooser means (16) to provide information about the plurality of servers to the terminal, the terminal being arranged to display this information so as to enable the user to select one of said servers for connection to the terminal; and

c) in response to a signal from the terminal indicating a user selection of one of said servers, initiating connection of the terminal to the selected server;

at least one of the plurality of servers having multiple processors, and the method being characterised by the steps of;

d) for a server having multiple processors, identifying that server in the storage means (90) by use of a genetic identifier for the processors within that server;

e) providing the address conversion means (92,

     94) with means (94) for periodically identifying one of the processors of that server based on predetermined criteria, and for updating the information in the address conversion means such that at any instant in time, the address associated with the generic identifier is the address of the identified processor; and

f) recognising at step (a) any genetic identifier, and deferring the referencing of the address conversion means (92,

     94) to determine the address associated with that generic identifier until after a user selection of the server corresponding to that generic identifier has been made.

9. A method as claimed in claim 8, further comprising the step of adapting the chooser means (16) to identify a user selection of a server represented by a generic identifier, and to respond to such a user selection by causing the address conversion means (92, 94) to be referenced to determine the address associated with that generic identifier.

10. A method as claimed in claims 8 or claim 9, wherein, upon retrieval at step (a) of data identifying the plurality of servers, the chooser means (16) contacts any of said servers which are not identified by a generic identifier to determine whether they are able to manage a connection with the terminal, but does not contact prior to user selection any server identified by a genetic identifier, the information thus displayed on the terminal at step (b) identifying any servers with generic identifiers, in addition to any other servers which the chooser means (16) has determined are able to manage the connection with the terminal.