Distributed technique for allocating calls

• US 6,646,990 B1
• Filed: 12/07/1999
• Issued: 11/11/2003
• Est. Priority Date: 12/09/1998
• Status: Expired due to Term

• Current Assignee: Mitel Networks Corporation
• Original Assignee: Zarlink Semiconductor Inc. (Microchip Technology Incorporated)
• Inventors: Gray, Thomas, Fullarton, Sonya
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): Molinari, Michael J.
• Application Number:
  US09/455,658
• Time in Patent Office: 1,435 Days
• Field of Search: 379/219, 379/220.01, 379/221.01, 379/221.05, 379/221.02, 379/221.06, 370/225, 370/392, 370/238, 370/252, 370/351, 709/238, 709/241
• US Class Current: 370/238
• CPC Class Codes: H04M 15/34 Charging, billing or metering arrangements for private branch exchanges
• CPC Class Codes: H04M 15/8044 Least cost routing
• CPC Class Codes: H04M 15/8083 involving reduced rates or discounts, e.g. time-of-day reductions or volume discounts
• CPC Class Codes: H04M 2215/0184 involving reduced rates or discounts, e.g. time-of-day reductions, volume discounts, cell discounts, group billing, frequent calling destination(s) or user history list
• CPC Class Codes: H04M 2215/42 Least cost routing, i.e. provision for selecting the lowest cost tariff
• CPC Class Codes: H04M 2215/745 Least cost routing, e.g. Automatic or manual, call by call or by preselection
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13138 Least cost routing, LCR
• CPC Class Codes: H04Q 2213/13144 Searching path through number of switching stages or nodes, e.g. revertive blocking
• CPC Class Codes: H04Q 2213/1322 PBX
• CPC Class Codes: H04Q 2213/13384 Inter-PBX traffic, PBX networks, e.g. corporate networks
• CPC Class Codes: H04Q 3/625 Arrangements in the private branch exchange
• CPC Class Codes: H04Q 3/66 Traffic distributors

Abstract

A method for minimizing toll call costs for completing a call at an originating PBX within a network of connected PBXs to a remote destination, comprising the steps of generating within the originating PBX and communicating to each other PBX within the network a message calling for bids from each PBX for least cost routing of the call according to respective local routing plans, determining within the originating PBX a least cost direct route for completing the call, determining from the respective local routing plans the least cost routing for each other PBX and communicating the bids to the originating PBX, and comparing and in response selecting within the originating PBX a least costly one of the least cost direct routes and the least cost routing for each other PBX for completing the call to the remote destination.

Claims

1. A method for minimizing toll call costs for completing a call at an originating PBX within a network of connected PBXs to a remote destination, comprising;

a) generating within said originating PBX and communicating to each other PBX within said network a message calling for bids from each other PBX for least cost routing of said call according to respective local routing plans;

b) determining within said originating PBX a least cost direct route for completing said call;

c) determining from said respective local routing plans the least cost routing for each said other PBX and communicating said bids to said originating PBX;

d) comparing and in response selecting within said originating PBX a least costly one of said least cost direct route and said least cost routing for each said other PBX for completing said call to said remote destination; and

e) imposing a first time limit for said step of determining from said respective local routing plans said least cost routing, and a second time limit for the steps of generating and communicating said message and selecting said least costly one of said least cost direct route and said least cost routing, wherein said first time limit is less than said second time limit.

2. The method of claim 1 wherein said message is transmitted successively from one said other PBX to a next said PBX.

3. The method of claim 2, further comprising the step of appending a list to said message at each said other PBX identifying each said other PBX to which said message has already been communicated.