Fault tolerant atm-based distributed virtual tandem switching system and method

Abstract

A System and method for reducing and surviving failures in a voice trunking over ATM (VTOA) environment includes a CS-IWF complex having a plurality of interconnected CS-IWF units, each unit having a plurality of processors. An end office building may also be provided for interaction with the VTOA system. The end office building includes multiple T-IWFs, and a switch that distributes calls among the T-IWFs in a load sharing manner. Each T-IWF has a plurality of processors and is part of the VTOA system. A switch management system is also provided in the VTOA system. In order to reduce and survive failures, the switch management system includes a plurality of switch management system units. At least one of the switch management system units is a backup unit for a primary switch management system unit. Each switch management system unit provides application redundancy within itself.

1 . A control and signaling interworking function (CS-IWF) system interacting with a virtual trunking system, the CS-IWF system performing call control functions for transmitting voice across a data network in the virtual trunking system, the CS-IWF system comprising: 
 a plurality of CS-IWF units, each of the plurality of CS-IWF units being connected to at least one data network switch, each of the plurality of CS-IWF units having a plurality of processors, at least one of the plurality of processors being configured to compensate for a failed processor, at least one CS-IWF unit being configured to absorb at least a portion of a workload associated with a failed CS-IWF unit, enabling the virtual trunking system to survive a simplex failure; and    a plurality of signaling gateways, each of the plurality of signaling gateways being connected to at least one of a pair of mated signaling transfer points (STPs), through a plurality of signaling link sets, and each of the plurality of CS-IWF units;    wherein the CS-IWF units are configured to interface narrowband signaling and broadband signaling for call processing and control within the data network.    
   
   
       2 . The system of claim of  1 , wherein calls originating and terminating within a public switched telephone network (PSTN) are transmitted through the data network.  
   
   
       3 . The system of claim of  1 , wherein the at least one data network switch comprises an ATM switch.  
   
   
       4 . The system of claim of  1 , further comprising a plurality of data network links that connect each of the plurality of CS-IWF units to the at least one data network switch.  
   
   
       5 . The system of claim of  1 , wherein each of the plurality of CS-IWF units operates one of an active mode or standby mode.  
   
   
       6 . The system of claim of  1 , wherein the plurality of CS-IWF units are configured to operate in a load-sharing mode.  
   
   
       7 . The system of claim of  1 , wherein the CS-IWF system is identifiable by a single point code.  
   
   
       8 . A control and signaling interworking function (CS-IWF) device, performing call control functions for transmitting voice across a data network, comprising at least one data network switch, in a virtual trunking system, the CS-IWF device comprising: 
 at least one processor, configured to compensate for a failed processor in the CS-IWF device or in at least one additional CS-IWF device;    a first interface for interfacing with the at least one additional CS-IWF device, the CS-IWF device being configured to absorb at least a portion of a workload of the at least one additional CS-IWF device, enabling the virtual trunking system to survive a simplex failure; and    a second interface for interfacing with a plurality of signaling gateways, each of the plurality of signaling gateways being connected to at least one of a pair of mated signaling transfer points (STPs), through a plurality of signaling link sets;    wherein each of the CS-IWF device and the at least one additional CS-IWF device are configured to interface narrowband signaling and broadband signaling for call processing and control within the data network.    
   
   
       9 . The CS-IWF device of  claim 8 , further comprising: 
 a third interface for providing call processing and control information to an originating trunking interworking function (T-IWF) unit and a terminating T-IWF unit over the data network, wherein each T-IWF unit has a plurality of processors and each T-IWF unit is capable of dynamically establishing an end-to-end connection to another T-IWF unit, so that calls originating or terminating within a public switched telephone network (PSTN) may be transmitted through the data network.    
   
   
       10 . The CS-IWF device of  claim 8 , wherein the data network comprises an Asynchronous Transfer Mode (ATM) network.  
   
   
       11 . The CS-IWF device of  claim 8 , wherein the data network comprises at least two disjointed routes between two end points.  
   
   
       12 . The CS-IWF device of  claim 8 , wherein the CS-IWF device operates in one of an active mode or standby mode.  
   
   
       13 . A fault-tolerant switch management system (SMS) for controlling a plurality of distributed switches in a virtual trunking system, the SMS comprising: 
 at least one backup SMS unit configured to operate in a standby mode when a primary SMS unit is operational and to operate in an active mode, performing functions of the at least one primary SMS unit, when the at least one primary SMS unit fails, the at least one primary SMS unit and the at least one backup SMS unit being connected to a data network through at least one data network switch, the connection allowing control communication among a trunking interworking function (T-IWF) complex, a control and signaling interworking function (CS-IWF) complex and at least one of the primary SMS unit and the backup SMS unit;    wherein the CS-IWF complex comprises a plurality of CS-IWF units configured to interface narrowband signaling and broadband signaling for call processing and control within the data network so that telephone calls originating or terminating within a public switched telephone network (PSTN) may be transmitted through the data network, and    wherein the T-IWF complex comprises a plurality of T-IWF units, each of the plurality of T-IWF units having a plurality of processors, each T-IWF unit being capable of dynamically establishing an end-to-end connection to another T-IWF unit.    
   
   
       14 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein each of the plurality of T-IWF units connect to the data network through at least one add/drop multiplexor (ADM).  
   
   
       15 . The fault-tolerant switch management system (SMS) of  claim 13 , the data network comprising at least two disjointed routes between two end points.  
   
   
       16 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein the SMS is located in one of a central office (CO) or a data center.  
   
   
       17 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein the SMS is Network Equipment Building Systems (NEBS) level  3  compliant.  
   
   
       18 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein the backup SMS unit is located at a location that is physically separate from the location of the primary SMS unit.  
   
   
       19 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein each of the at least one primary SMS unit and the at least one backup SMS unit comprises a database storing at least one of a system user, a networking software, a network inventory and security information.  
   
   
       20 . The fault-tolerant switch management system (SMS) of  claim 13 , wherein the connection to the at least one data network switch comprises a multi-homed connection.