High availability distributed call processing method and apparatus

• US 6,298,039 B1
• Filed: 01/31/1998
• Issued: 10/02/2001
• Est. Priority Date: 01/31/1998
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Lin, Yow-Jian, Murakami, Kazutaka, Ramjee, Ramachandran, Buskens, Richard Wayne, La Porta, Thomas F.
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): MEHRA, INDER P
• Application Number:
  US09/017,105
• Time in Patent Office: 1,340 Days
• Field of Search: 370/216, 370/242, 370/244, 370/310, 370/328, 370/260, 709/100, 709/226, 709/303, 714/1, 714/2, 714/5, 714/4, 714/15
• US Class Current: 370/216
• CPC Class Codes: G06F 11/1482 by means of middleware or OS functionality
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04Q 3/0037 involving call modelling techniques, e.g. modifications to the basic call state model [BCSM]

Abstract

A method of delivering highly-reliable, fault-tolerant communications services in a telecommunications network of distributed call processing systems. The method advantageously identifies a set of objects within the telecommunications network requiring checkpointing; checkpoints the objects; and subsequently restores the checkpointed objects in the event of a failure. Various aspects of the method are disclosed, including restoration strategies.

Claims

1. A method of delivering high-reliability, fault-tolerant communications services within a telecommunications network comprising the steps of

identifying a set of objects within the telecommunications network requiring checkpointing wherein said set of objects are identified by

first, determining a set of global objects within the telecommunications network requiring checkpointing;

second, identifying duplicate objects within the global object set;

third, determining, which ones of said duplicate objects require checkpointing; and

fourth, eliminating, from the global object set, duplicate objects which do not require checkpointing;

checkpointing the objects upon the occurrence of a particular event; and

restoring the checkpointed objects upon the occurrence of a predetermined event.

2. The method according to claim 1 further comprising the step of:

determining one or more states of the telecommunications network requiring restoration.

3. The method according to claim 2 wherein said checkpointing step is performed when committing to a stable state.

4. The method according to claim 2 wherein said checkpointing step is performed when new state information is obtained that is required to undo a resource allocation.

5. The method according to claim 2 wherein said checkpointing, step is performed when new state information is obtained that is required to redo a resource clearing.

6. The method according to claim 3 wherein said stable state is an active call in the telecommunications network.

7. The method according to claim 4 wherein said resource allocation is characterized by reserving a set of network resources during a transition from a null state to an active state.

8. The method according to claim 5 wherein said resource clearing is characterized by returning a call processing state machine to a null state from an active state.

9. The method according to claim 1 wherein said restoring step comprises the steps of:

detecting state inconsistencies; and

resynchronizing the states of related objects among distributed servers.