Switch controller for a telecommunications network

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to providing an interface between components within a telecommunications network.

BACKGROUND OF THE INVENTION

Telecommunications service providers desire to offer enhanced services to customers. However, current technology is expensive and available only to handle large call volumes. As a result, some telecommunications service providers cannot offer enhanced services. Even if a telecommunications service provider can offer enhanced services to a calling area, the telecommunications service provider must charge rates substantially higher than other services in order to compensate for the cost of equipment.

Enhanced services are telecommunications network products that offer features that differ from traditional dial-1 service. Telecommunications network products are services provided by telephone companies that are carried on telecommunications networks. A widely known telecommunications network product is dial-1 long distance voice service which allows a customer to dial a 1 plus a ten digit number from his or her home telephone, talk to a party who answers the telephone on the line of the ten digit number dialed, and pay for the telephone call when billed at the end of the month.

Although dial-1 is popular, other services, referred to as enhanced services, are sometimes preferable. Some enhanced services allow customer calling and payment options that differ from traditional dial-1 service. For example, debit calling allows an individual to make a call from a phone other than their home phone and charge the call to the debit account. With debit calling, also referred to as prepaid calling, a customer puts funds in an account and has those funds debited each time a telephone call is made. Another calling and payment option is collect calling in which the call is billed to the receiving party's account. However, enhanced services are not limited to other calling and payment options. Enhanced services can provide a customer with information such as access to news and weather. Another enhanced service is 1-800-MUSICNOW which gives a telephone caller the ability to select and listen to music and then order a recording of the music by entering selections in response to menu prompts using the keypad of the telephone.

Enhanced services are possible because intelligent services networks (ISNs) within telephone companies telecommunications networks have advanced capabilities needed to process the enhanced service calls. Much of the advanced capability is provided by two particular components within the intelligent service network, the automatic call distributor (ACD) which provides the call switching and queuing functions and the intelligent service network applications processor (ISNAP) which provides monitoring and control of queued calls for the ISN.

Unfortunately, ACDs are typically only available with capacity to handle a large call volume. In addition, ACDs are generally very expensive. Because the ACD is generally expensive, the ACD typically determines the size and capacity of an ISN. Many smaller sized telecommunications carriers and private entities desire to employ ISN capability, but do not have sufficient call volumes to justify the expense of a traditional large-scale ACD. The ISN architectures that are available today cannot be scaled to the appropriate port capacity for small or moderate call volumes. This prohibits both small and large companies from utilizing ISNs where they are commonly needed. Although smaller switches are available, they are not capable of performing many ACD functions needed for enhanced services.

Another problem encountered with a large-scale ACD-based ISN is the development cost and cycle of ACDs. Often the deployment of new services for the ISN or enhancement to existing services on the ISN require modifications to the ACD. The ISN service provider must subject itself to the ACD vendor's development costs and time.

SUMMARY OF THE INVENTION

The present invention is an intelligent services network (ISN) that uses a switch controller. The switch controller controls the operation of one or more programmable switches which provide switching functionality between the telecommunications network and components on the ISN. The programmable switches perform the switching functionality traditionally performed by automated call distributors (ACDs) at a lower cost and allow for more flexibility in sizing for smaller call volumes. In addition, the switch controller provides an interface to other components on the ISN that provide interface with callers and other networks to provide enhanced service functionality and access to data and services of other networks. The switch controller performs many functions for the interface to other components on the ISN traditionally performed by (ACDs) including call routing and call queuing. However, unlike ACDs, service logic programs within the switch controller provide these functions. Service logic programs provide greater efficiency and allow the switch controller to be easily upgraded to handle new enhanced services. The switch controller also performs the functions traditionally performed by the intelligent service network applications processor (ISNAP) including monitoring and control of queued calls. In addition, the switch controller performs other functions needed for enhanced service call processing, such as functions needed for prepaid call processing.

Use of switch controllers and programmable switches in place of ACDs allows an ISN to be scaled to an appropriate port capacity for the entity desiring to provide enhanced telecommunications services. To scale an ISN to a needed port capacity, programmable switch ports can be added or removed without having to modify the switch controller or add more switch controllers. In addition, switching functions for remote programmable switches can be controlled by the switch controller. This allows a programmable switch at one ISN to be connected to a programmable switch at another ISN. Interconnection between programmable switches enables one ISN to automatically backup another ISN. An ISN can receive calls from another ISN without call transfer over the public switched telephone network.

A scalable ISN architecture allows small service providers to deploy an ISN that suits their needs. It also allows any service provider to deploy ISNs in a greater number of locations, such as in foreign countries, where a large-scale ISN may not be economically practical. Also, as the volume of traffic handled by an ISN grows, additional programmable switches may be added at marginal expense. To expand the capacity of an ACD-based ISN, a second ACD would be needed which is extremely expensive and often prohibitive. Even if a high call volume ISN is desired, an ISN with a switch controller and programmable switches can be implemented with the same capacity as an ISN with an ACD at a significantly lower cost.

An additional benefit of implementing an ISN using a switch controller and programmable switches is that because the switch controller uses service logic programs to provide enhanced services, the switch controller can be easily upgraded to handle new enhanced services. As a result, development time and costs are reduced.

Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digits in the corresponding reference number.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1

is a block diagram of a switch controller environment according to one embodiment of the present invention;

FIG. 2

is a block diagram of a multipurpose intelligent service network according to one embodiment of the present invention;

FIG. 3

is a block diagram of a switch controller hardware configuration according to one embodiment of the present invention;

FIG. 4

is a block diagram of a switch controller application program according to one embodiment of the present invention;

FIG. 5

is a block diagram of an intelligent service network message interface according to one embodiment of the present invention;

FIG. 6

is a block diagram of a call control function according to one embodiment of the present invention;

FIG. 7

is a block diagram of the call state machine interface according to one embodiment of the present invention;

FIG. 8

is a flowchart of call state machine processing according to one embodiment of the present invention;

FIG. 9A

is a block diagram of dynamic detection point processing according to one embodiment of the present invention; and

FIG. 9B

is a block diagram of detection point processing based on state according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1

is a block diagram of a switch controller environment

102

according to one embodiment of the present invention. Switch controllers

112

a

,

112

b

, . . .

112

n

are within intelligent service network ISNs

108

a

,

108

b

, . . .

108

n

to provide access for a call initiated via a public switched telephone network (PSTN)

106

to ISN components

116

a

,

116

b

, . . .

116

n

(

116

) also within ISNs

108

. Except as otherwise noted, when elements of the switch controller environment

102

are referred to generally, they will be referred to with a number designation and not a letter designation.

Switch controllers

112

are the central point of control and interface within ISNs

108

. The switch controllers

112

are interconnected to programmable switches

110

to provide commands to control programmable switches

110

a

,

110

b

, and

110

n

. The LANs, WANs, and routers (or any other connectivity)

114

are connected to switch controllers

112

and the ISN components

116

to provide connectivity between the switch controllers

112

and the ISN components

116

. Exemplary ISN components

116

include manual operator consoles (MOCs), automated response units (ARUs), databases, and protocol converters. The MOCs and ARUs are personal computers (PCS) that interact with a caller to provide operator services, customer services, and other enhanced services. Databases contain stored information and may be a single database or multiple databases connected to and controlled by a server system. Protocol converters are connected to external networks and resources

118

and provide protocol conversion and other processing necessary for interface between the PSTN

106

and external networks and resources

118

. Intelligent service networks

108

are described in further detail in copending U.S. patent application Ser. No. 09/096,936, filed Jun. 12, 1998, entitled, “Intelligent Service Network Using a Switch Controller” incorporated herein by reference. The ISN components

116

will be described in further detail with respect to FIG.

2

.

The switch controller environment

102

includes components external to ISNs

108

. In addition to one or more ISNs

108

a

,

108

b

, . . .

108

n

, the switch controller environment

102

includes one or more calling devices

104

a

,

104

b

, . . .

104

n

(

104

), such as a telephone, a public switch telephone network (PSTN)

106

, and external networks and resources

118

. The calling device

104

used by the caller is connected to PSTN

106

. The PSTN

106

provides switching and connectivity to the ISNs

108

. The ISNs

108

may provide enhanced service functionality, network integration, and other functions. Network integration is illustrated using exemplary ISN component

116

b

that is connected to external networks and resources

118

. External networks and resources

118

include financial processors, information databases, and Internet facilities. Exemplary ISN component

116

b

provides an interface to one of the external networks and resources

118

. In addition to providing connectivity to external networks and resources

118

, the ISN components

116

provide enhanced service call processing. Exemplary enhanced services include manual operator service, prepaid calling, calling card, 1-800-COLLECT, and 1-800-MUSICNOW.

The ISN environment

102

can best be described referencing the processing of a typical call. The exemplary call will be for a service that requires human operator intervention. The call is placed by a caller using a calling device

104

A. Calling devices

104

are any devices that can place or receive a call. Exemplary calling devices

104

include telephones, facsimile machines, and personal computers.

The call is received by PSTN

106

. The PSTN

106

comprises multiple telecommunications networks including local exchange networks and interexchange networks. A local exchange network comprises switches and termination equipment within a localized area. An example of a local exchange network is a local telephone operating company network, such as Bell Atlantic. An interexchange network comprises a plurality of switches, also referred to as exchanges, distributed throughout a geographic area large enough to process long distance telephone calls. For example, a national interexchange network comprises switches located throughout the nation. When the call is routed to either a local exchange network or an interexchange network, the call is routed to one or more switches within the network.

The PSTN

106

is interconnected to a programmable switch

110

A within an ISN

108

A. Programmable switches

110

have basic switching matrices that provide switching functionality for access to ISNs

108

. An ISN

108

A may include one or more programmable switches

110

interconnected to one switch controller

112

A or to additional switch controllers

112

B-

112

n

. Configurations of ISNs are illustrated in more detail in copending U.S. patent application Ser. No. 09/096,936, filed Jun. 12, 1998, referenced above. Programmable switches

110

are dumb switches that can connect ports and process calls based on external commands. Examples of programmable switches

110

include those built by Excel and Summa Four. Excel programmable switches

110

come in sizes ranging from 512 ports to 8,000 ports.

The ISN

108

a

has a sizable architecture because the number of programmable switches

110

and the configuration of the programmable switches

110

can vary depending on the desired port requirement of the ISN

108

a

. Programmable switches

110

manufactured by Excel can support various signaling systems such as Signaling System Number 7 (SS7) and can be connected directly to the signaling network of a PSTN

106

. If multiple programmable switches

110

are interconnected to one or more switch controllers

112

, connections between the programmable switches

110

and the switch controllers

112

may be via a LAN (not shown), such as an Ethernet LAN, using transmission control protocol/internet protocol (TCP/IP). The TCP/IP is used by various data networks including many Internet servers.

Each of the programmable switches

110

is connected to the PSTN

106

via voice telephony trunks, also referred to as lines. Typical telephony trunks are capable of carrying high speed digital data.

The voice trunk connectivity between the programmable switches

110

and the PSTN

106

includes equipment that provides signaling functionality. Equipment within telecommunications networks send signals to each other to communicate information for call processing, such as the origination and destination information, current state of the call processing, equipment being used for the processing, etc. Even if equipment is in-service, if it is incapable of signaling to other equipment, it cannot be used for call processing. Because of the importance of signaling to call processing, sophisticated signaling techniques are used, such as signaling system number 7 (SS7) protocol. Specialized equipment within the telecommunications network (not shown) provides SS7 functionality. Signaling System Number 7 may be implemented using Token ring LANs (not shown) connected to a signal transfer point (not shown). If the programmable switch is not capable of SS7 signaling or other signaling used by the PSTN

106

, the ISN

108

architectures may include a signaling gateway between the signaling transfer point and the programmable switches

110

to facilitate in conversion between the signaling used by the programmable switches

110

and the signaling used by the PSTN

106

. The current industry standard of SS7 protocol is published in the International Telecommunications Union (ITU) Signaling System Number 7 (SS7) Integrated Services Digital Network (ISDN) User Part (ISUP) NCT1.113 (1995) document and the International Telecommunications Union (ITU) Signaling System 7 (SS7) Message Transfer Part (MTP) NCT 1.111 (1992) document which are incorporated herein by reference in their entirety.

Exemplary switch controller

112

a

is connected to programmable switches

110

to provide external commands to control call processing. The switch controller

112

a

provides the commands to exemplary programmable switch

110

a

carrying the exemplary call to perform call processing functions. When the programmable switch

110

a

receives the call from the network it sends a message to the switch controller

112

a

. The switch controller

112

a

determines the call processing needed and returns commands to the programmable switch

110

a.

In addition, the switch controller

112

a

provides access to ISN components

116

. The switch controller

112

a

interfaces with ISN components

116

via LANS, WANs, routers (or any other connectivity)

114

using network information distribution system (NIDS) sequenced packet protocol (NSPP) on top of user datagram protocol/internet protocol (UDP/IP). The NSPP is a session oriented packet exchange protocol that is implemented over UDP/IP. It is designed to allow rapid information exchange between client applications and NIDS server processes. The use of TCP/IP between switch controller

112

A and the programmable switch

110

A and the use of NSPP/UDP/IP for communications via LANs, WANs, routers (or any other connectivity)

114

illustrate exemplary protocols but communication is not limited to these protocols.

The ISN components

116

include components that provide enhanced service functionality and connectivity to external networks and sources

118

. The ISN components

116

will be described in further detail with respect to FIG.

2

.

FIG. 2

is a block diagram

202

of a multipurpose ISN

203

. The multipurpose ISN

203

illustrates exemplary ISN components

116

that may be included in ISNs

108

. The switch controller

112

a

has the capability to interface with the various types of ISN components

116

in order to process calls.

In addition to the ISN components

116

and the switch controller

112

a

, the multipurpose ISN

203

includes one or more programmable switches

110

a

,

110

b

. . .

110

n

(

110

) that provide an interface via connections to the PSTN

106

. The programmable switches

110

are interconnected to the exemplary switch controller

112

a

. The switch controller

112

a

is connected to the ISN Ethernet LAN

214

which is one embodiment of LANs, WANs, and routers (or any other connectivity)

114

. Except as otherwise noted, when elements of the multipurpose ISN

203

are referred to generally, they will be referred to with a number designation and not a letter designation.

Various types of ISN components

116

include intelligent peripherals, databases and servers, protocol converters

232

, and personal computer (PC) systems that provide configuration and management of the switch controller

112

a

and/or the programmable switches

110

. The switch controller

112

a

includes the capability to interface with the different types of ISN components

116

as will be described in further detail with respect to FIG.

4

.

Connected to both the programmable switches

110

and the ISN Ethernet LAN

214

are intelligent peripherals including manual operator consoles (MOCs)

210

a

,

210

b

, . . .

210

n

(

210

), automated response units (ARUs)

204

a

,

204

b

, . . .

204

n

, and other intelligent peripherals

212

a

,

212

b

, . . .

212

n

(

212

). The MOCs

210

are PC workstations that are operated by live operators or call center agents to provide operator services, customer services, and other enhanced services requiring human operator intervention. The MOCs

210

are housed in an Operator Network Center (ONC) (not shown). An ONC is a site that houses the MOCs

210

. The ONC may be physically remote from the other components of the multipurpose ISN

203

. The MOCs

210

are connected to a distinct ONC LAN which is also an Ethernet LAN. The ONC LAN and the ISN Ethernet LAN

214

are connected via routers, and essentially operate as a single LAN, shown as the ISN Ethernet LAN

214

in FIG.

2

. The ONC LAN also includes various servers for system monitoring, booting (system initialization), and other applications.

The ARUs

204

are comprised of network audio servers (NASs)

206

a

,

206

b

, . . .

206

n

and automated call processors (ACPs)

208

a

,

208

b

, . . .

208

n

. The ARUs

204

are used to provide automated operator services and interactive voice response services. The ACPs

208

a

,

208

b

, . . .

208

n

(

208

) are high performance personal or midrange computers that perform intelligent application processing to determine which services to provide. The NASs

206

a

,

206

b

, . . .

206

n

(

206

) are specialized computers equipped with telephony ports which provide audio responses and collect caller input via dual tone multifrequency (DTMF) signals and voice recognition based on commands provided by the ACP

208

. The ACPs

208

communicate with the NASs

206

via LANs, WANs, and routers (or any other connectivity)

114

. Each ARU

204

and MOC

210

is connected to one or more programmable switches

110

via voice trunks. Both MOCs

210

and ARUs

204

are also referred to as agents. Other intelligent peripherals

212

a

,

212

b

, . . .

212

n

(

212

) can be used in an ISN to provide various call services. Other intelligent peripherals

212

are also connected to one or more programmable switches

110

via voice trunks.

Additional examples of ISN components

116

are NIDS servers

216

a

,

216

b

, . . .

216

n

(

216

) and the NIDS database

218

. The NIDS servers

216

are connected to the ISN Ethernet LAN

214

and to the NIDS database

218

. A NIDS database

218

stores data related to call processing such as customer accounts and routing translations. When an ISN component

116

, such as an ARU

204

or a MOC

210

, receives a call, it may query a NIDS server

216

via the ISN Ethernet LAN

214

for data stored in the NIDS database

218

. In addition, NIDS servers

216

receive data from mainframe-based systems

224

to be used during real time call processing. Mainframe databases and a data distribution system (DDS)

224

are connected to a token ring LAN

222

. The token ring LAN

222

is connected to the NIDS servers

216

. Order entry and data management functions are performed within mainframe based systems

224

. Mainframe computers are used as the databases of record for call processing data. The DDSs distribute call processing data stored in mainframe computers over a token ring LAN

222

to each NIDS server

216

. In addition, other service application database servers

220

a

,

220

b

, . . .

220

n

(

220

) are connected to the ISN Ethernet LAN

214

and to the token ring

222

. An exemplary other service application database server

220

is a server to process prepaid calls.

The ISN components

116

also include protocol converters

232

a

,

232

b

, . . .

232

n

that convert between various telecommunications protocols. Protocol converters

232

provide protocol conversion between different protocols such as TCP/IP, NSPP on top of UDP/IP, and packet switching protocols, such as X.25. Exemplary components that perform protocol conversion are the advanced intelligent network gateway (AIN) described in U.S. patent application Ser. No. 08/967,339, filed Oct. 21, 1997, now U.S. Pat. No. 6,229,819, entitled, “Advanced Intelligent Network Gateway”, and the validation gateway described in U.S. patent application Ser. No. 08/956,220, filed Oct. 21, 1997, now U.S. Pat. No. 6,160,874, entitled, “Validation Gateway,” incorporated herein by reference. The capabilities of the components described in the previously referenced applications are not limited by the examples given and are defined by the scope of the claims in the applications.

Protocol converters

232

are connected to external networks and resources

118

. Exemplary external networks and resources

118

include financial processors with credit card information, the Internet, and other databases, such as those used in processing international calls.

Additional ISN components

116

include computers for system management

226

, force management

228

, and provisioning/configuration

230

. Each of these systems may be implemented on a different computer, such as a PC workstation, as is shown in FIG.

2

. Alternately, they can be embodied on the same computer workstation, and can even be the same process and GUI. System management

226

includes system monitoring of the switch controller

112

A and the programmable switches

110

, collection of alarms, call state monitoring, call state triggering, resource monitoring, and resource state triggering. Force management

228

is the management and monitoring of a ONC's work force (i.e. agents). Force management

228

receives a download of statistical and historical agent information through the interface and uses the information to monitor and manage the agent population supported by the switch controller

112

a

. Provisioning and configuration

230

includes the provisioning and configuration of programmable switch resources

110

(i.e. ports), ARU

204

, MOC

210

, and other intelligent peripheral

212

resources, and other resources. Computers that perform system management

226

, force management

228

, and provisioning/configuration

230

, are connected to the ISN Ethernet LAN

214

. This provides an interface to the switch controller

112

.

Additional information concerning ISN components

116

is provided in copending U.S. patent application Ser. No. 08/956,232 filed Oct. 21, 1997, now U.S. Pat. No. 6,188,761, entitled, “A System and Method for Providing Operator and Customer Services for Intelligent Overlay Networks,” incorporated herein by reference.

FIG. 3

is a block diagram of the hardware configuration of an ISN

108

. The switch controller

112

, programmable switches

110

, and ISN components

116

of the present invention are preferably implemented using computer systems as shown in

FIG. 3. A

computer system includes a processor, such as processor

304

connected to bus

316

. Also connected to bus

316

is main memory

306

(preferably random access memory, RAM) and secondary storage devices

308

. The secondary storage devices

308

include, for example, a hard drive

310

and a removable storage medium drive

314

(such as a disk drive, for example).

The application programs of these components are preferably computer programs that reside in main memory

306

while executing. When executing, the computer programs enable the computer system to perform the features of the present invention as discussed herein. Thus, the application program represents a controller of the computer system (and of the processor

304

). Alternately, the application program is predominately or entirely a hardware device, such as a hardware state machine.

In one embodiment, the present invention is a computer program product (such as removable storage medium

314

, representing a computer storage disk, compact disk, etc.) comprising a computer readable media having control logic recorded thereon. The control logic, when loaded into main memory

306

and executed by processor

304

, enables the processor

304

to perform the operations described herein.

FIG. 4

is a block diagram of switch controller application program

402

. The switch controller application program

402

resides in memory of the switch controller

112

. The switch controller application program

402

may reside in main memory

306

or in a secondary memory device

308

such as the hard disk

410

a

or the removable medium

314

. The switch controller application program

402

resides in memory while executing. The switch controller application program

402

is executed by processor

304

.

The switch controller application program

402

comprises multiple routines. Software routines, also referred to as functions and processes, are elements of a computer program or application program. Software routines are sub-sets of a computer program or application program (i.e., groups of lines of code) that perform one or more functions. The software routines within the switch controller application program

402

form the computer software code of the switch controller application program

402

and reside in memory while executing. Software routines are processed by processor

304

during processing of the switch controller application program

402

.

The software routines of the switch controller

112

are categorized into five functions: programmable switch support function

404

, call control function

406

, service control function

408

, resource control function

410

, and management interface function

412

. Communication between the software routines of the switch controller

112

is performed using switch controller application programmer interface (SCAPI) messages. The switch controller application programmer interfaces and SCAPI messaging is described in further detail in copending U.S. patent application Ser. No. 09/096,937, filed Jun. 12, 1998, entitled, “Switch Controller Application Programmer Interface” incorporated by reference herein.

The programmable switch support function

404

provides an interface between switch controller

112

a

and a programmable switch

110

a

. The programmable switch support function

404

translates messages between a generic switch controller application programmer interface (SCAPI) message format and programmable switch API message format, manages message header/trailer requirements, and controls connectivity to the programmable switch

110

. The generic SCAPI message format is used for messages transmitted between the routines of the switch controller application program

402

within the switch controller

112

a

. Further description of the programmable switch support function is provided in Table 1 below.

TABLE 1

Switch Support Module Functions

Function

Description

Translation of Switch

One to one translation between Switch

Controller “generic”

Controller API message format and Excel

messages to/from Excel

message format. ISUP messages are passed

specific format

unmodified to the Call Control process. The

programmable switch support function

encodes and decodes the matrix specific

message set, extracts call processing

information from the messages, and

encodes/decodes the messages in the generic

Switch Controller API (SCAPI) format.

Manage Excel message

Hides switch-specific interface details, such

header/trailer

as API message framing, checksum, retries,

requirements

sequence numbers. For messages sent to the

programmable switch, generate the framing

and sequence numbers required for each

message and generate the trailing checksum.

Routing of translated Excel

Switch management and status messages are

messages to the appropriate

routed to the System Control process. Call

process

Control messages are routed to the Call

Control Process. Switch alarm messages are

routed to the System Management Interface

process.

Controlling connectivity

Initiate and manage redundant TCP/IP socket

to the Excel switch (Switch

connections to the active and standby switch

management)

matrix CPUs. Responding to Excel switch

“poll” messages. Comparing consecutive

“poll” messages for a change in state which

requires notification to the System Control

process.

Implementing “macro”

“Initialize” macro request, which attempts a

switch control functions for

connection to the switch, compares the latest

the System Control Process

poll information to the initialization paramet-

ters and possibly performs the following

steps:

Setting the internet protocol (IP)

address of each Switch CPU.

Downloading the system software.

Re-connecting to the switch matrix.

Compare the status returned in the poll

message and acknowledge the System

Control.

Report any errors to the System

Control.

Configure macro request, which provides:

An ordered list of configuration files

are read and parsed in a serial fashion.

As the file is parsed, Excel

configuration messages are encapsulated

with the appropriate header and trailer and

transmitted to the switch.

All errors are reported to the System

Control, indicating that the affected re-

sources did not configure properly.

Once all files are parsed, acknowledge

the System Control process.

The call control function

406

provides service independent call processing. The call control function

406

is designed generically and is not service specific. Service specific features are handled by the service control function

408

. The call control function

406

includes a call state machine that is used for call processing. The call state machine performs call processing by analyzing call processing information with respect to the current state as defined by the basic call state machine model. The call state machine will be described in further detail with respect to

FIGS. 6 and 7

.

The call control function

406

performs various functions including but not limited to: detecting an incoming call, creating an originating call model, collecting originating dial digits, requesting analysis of the digits, selecting trunk groups, creating a terminating call model, composing and sending messages to the terminating agent or party, detecting Integrated Services Digital Network User Part (ISUP) messages, detecting disconnect signals, and triggering enhanced services. The ISUP messages are described in further detail with respect to FIG.

5

. The call processing functions performed by the call control function

406

are described in further detail in Table 2.

TABLE 2

Call Processing Functions of Call Control Function

Function

Description

Detect incoming call

Arrival of initial setup message from the net-

work (e.g., initial address message IAM)

Originator allocation

Creating Originating call model (may be

basic call state model)

Receive digits

Collecting originator dialed digits (from IAM)

Translate digits

Request analysis of the digits to determine an

Operator group to handle the incoming call

Router

Select the right trunk group

Terminal allocation

Creating Terminating Call Model

Signal terminating agent

Compose and send messages to the terminating

agent

Detect answer

Detect answer message; Collect billing data

Detect disconnect

Detect disconnect message; Collect billing data

Trigger features and

Analyze static criteria in order to initiate fea-

services

ture and service processing allow per call cri-

teria to be set via a well defined set of rules in

order to initiate feature and service processing

The call control function

406

allocates a region of memory, referred to as a call data block. The call data block is used as transient storage for call data. Data in the call data block is accessible to the other switch controller application program

402

functions. Use of the call data block allows the service specific processing to be performed by a function, specifically the service control function, that is separate from the call control function

406

. The call data block is a table within resource management

422

. Data in the call data block is accessed using resource management application programmer interfaces. The call data block will be described in further detail in copending U.S. patent application Ser. No. 09/096,939, filed Jun. 12, 1998, entitled “A System and Method for Resource Management” incorporated by reference herein in its entirety. Data stored by the call data block is described further in Table 3.

TABLE 3

Call Data Block Information

Call Data Block

Information

Description

Call Identifier

A unique ID which is given to a call within the

network

Call State

The call state (e.g., call setup, speech, etc.)

Leg Identifiers

ID of legs in the call

Leg States

States of legs in the call

Originating Call Model

A pointer to the call record associated with the

Record Pointer

originating call model

Terminating Basic Call

A pointer to the call record associated with the

Model Record Pointer

terminating call model

Billing Time Points

Time stamps generated during a call that are

used to determine the appropriate charge to be

billed to the customer.

Call Statistics

Statistics for total calls handled by the call con-

trol function 406 for a specified period of time.

Call statistics are useful for performance

information and capacity requirements.

As shown in Table 3 above, billing time point data is stored in the call data block. Billing time point data is one or more time stamps that are generated during the call. The time stamps indicate that progress of the call which is used to determine the appropriate charge to be billed to the customer. For example, if a customer's call proceeds to an agent position but the agent does not complete processing, the customer may be billed differently than both a customer that simply initiated a call but did not proceed to an agent position and a customer that completed a call. The billing time points stored in the call data block are shown in Table 4 below.

TABLE 4

Billing Time Points

Time Stamps

Generated

Description

TP1

The time Switch Controller detects an incoming call

TP4

The time a call is offered to an Agent Position

TP6

The time the Agent port is done with the call

TP6

The time which Switch Controller detects an Answer

TP7

The time which Switch Controller detects

Re-organization DTMS sequence

TP7

The time which Originator Disconnects

TP7

The time which Terminator Disconnects

TP7

The time which call Park Timer expiration

TP7

The time Switch Controller transfers a call to another

Switch Controller if there are no Manual (or

Automated) Operators to handle the incoming call

Call statistics are also stored in the call data block

1

(shown in Table 3). Call statistics are calculated for total calls handled by the call control function

406

for a specified period of time. An exemplary call statistic is the number of calls processed successfully by the call control function

406

. Call statistics are useful for performance information and capacity requirements. Additional call statistics are shown in Table 5 below.

TABLE 5

Call Statistics Maintained by the Call Control Module

Call attempt notification

Calls receiving Congestion Treatment

Calls processed successfully

Billing timepoints

Processor outage statistics

Busy Hour Statistics

Total number of calls that were in queue and got abandoned due to timeout

Time before call was answered

Operator statistics (operator connect time, type of call, number of

transfers)

Real time statistics (queue statistics, agent status)

Total number of trunk group congestions

A subset of the call statistics is alarm and notification data. Alarm and notification data is collected and used to produce the call statistics shown in Table 5 above. Alarm and notification data tracked by the call control function

406

is shown in Table 6 below.

TABLE 6

Alarms and Notifications Tracked by the

Call Control Function

Alarm/

Notification

Alarms and Notifications

Configurable

Type

Tracked

Components

Call

Queue timeout

Severity Level,

Abnormally

Queue overflow

Alarm Description,

released

No route available

Action

All routes busy

Recommendation

Vacant destination number (DN)

(no translation)

Protocol timeout

System failure

Invalid Call State

Long Call Disconnect

Call Control

Low memory

Failure

Message Buffer High Water Mark

Corrupt Call State

Call congestion

Switch outage

Queue Congestion

Resource Congestion

Invalid

Severity Level,

Event/Message

Alarm Description,

Action

Recommendation

Recovery

Severity Level,

Mode

Alarm Description,

Action

Recommendation

The service control function

408

includes a switch service process

414

which is an interface to the ISN components

116

and one or more service logic programs that provide enhanced service call processing. The service logic programs include group select

416

, call queuing

418

, and other service logic programs

420

a

,

420

b

, . . .

420

n.

The use of service-specific service logic programs within the service control function

408

hides service-specific features from the remaining call processing functions. Service logic programs provide flexibility to the switch controller

112

design because new services can be added by simply adding a service logic program rather than modifying the call control function

406

and functions that interact with the call control function

406

.

The group select service logic program

416

assists in routing calls by identifying groups of ports associated with the type of ISN component

116

needed to process the call. For example, if a call requires processing with an intelligent peripheral, such as a manual operator console

210

, the group select service logic program

416

determines the groups of ports on the programmable switches

110

associated with manual operator consoles. As shown in

FIG. 2

, intelligent peripherals have voice circuit connections with ports on the programmable switches

110

. Programmable switch

110

ports are grouped by the type of intelligent peripheral to which the port terminates. The group selected service logic program

418

determines the port groups of the intelligent peripheral type needed to process the call. The type of intelligent peripheral required is determined by analyzing the incoming digits.

A second service logic program used for call routing is the call queue service logic program

418

. After the type of ISN component

116

needed to handle the call is determined, the call queue service logic program

418

uses an algorithm based on availability to determine which group, among the groups corresponding to the needed type of ISN component

116

, should receive the call. The call queue service logic program

418

has the capability to send the call immediately to an available ISN component

116

or to queue the call to a group. Queuing a call holds the call for a period of time and perhaps apply treatment (i.e., play music). Call queues are managed based on thresholds such as a threshold number of calls that may be in a queue. If a call comes into an ISN

108

and all of the queues for the type of ISN component

116

needed to process the call have the number of calls specified by the threshold, the call will be transferred to another ISN

108

or the caller will be denied the ability to place the call. The call queue SLP

418

generates the commands needed to hold the call in queue on the programmable switch

110

, determines call treatment, determines how long a call should be queued, determines when a queued call should be dropped, and determines if a queued call should be transferred.

Additional information about each of the processes within the service control function

408

is provided below in Table 7.

TABLE 7

Processes of the Service Control Function

Process

Description

Major Functions

Switch

The Switch Service process serves

NIDS session maintenance

Service

as the interface process between

Transmission control (TC)

Module

ISN components and the other

message encode and de-

processes within the Switch

code -- Messages to ACP

Controller. This process

and MOC are converted

implements NIDS server interface

from internal SCAPI

towards ISN MOC and ARU

format to TC format.

clients

Routing of TC message to/

from internal Switch Con-

troller processes:

Call processing related TC

message from ACP and

MOC are passed to Opera-

tor Service Logic process

within the Switch

Controller.

Agent status related

messages are passed to

System Control Process

within the Switch

Controller

Service Logic Program

Interface

Send and receive modules

that provide timing and

interface with UDP/IP and

TCP client

Group

Group select process implements

Maintain ISN component

Select

business-specific algorithm for

groups per product or

Module

selecting ISN component groups to

service supported.

handle incoming calls. Group

Analyze incoming call

selection of ISN components

parameter such as access

provides the ability to route

number to select a group.

incoming calls to the correct type

Maintain group statistics.

of ISN component based on the

Map terminal identifier

incoming call parameters such as

(TID) to a voice port.

access number. The call control

function requests this process to

obtain groups that are associated

with ISN components that can

handle a particular incoming call.

This process consults its internal

group select tables and returns the

group identifier.

Call

The process checks the availability

Determine using algorithm

Queu-

of ports on the ISN components

if port available

ing

within a group. It implements the

If no port available, queue

Module

logic to queue the process when no

call and set timer

port is immediately available. The

If port becomes available

call control function requests this

before expiration of timer,

process for an available port within

allow call to proceed

a specific group.

If timer expires, release call

Notify the call control

module

Every queue is configured

with a queue timer that de-

termines the maximum

duration the call can wait

in the queue

Queue parameters such as

length of the queue and

queue timer are configur-

able as well as changeable

through a System

Management Console

Opera-

This process receives call

Sending/receiving call

tor

processing related messages from

processing SCAPI mess-

Service

the Switch Service process. These

ages to/from switch service

Logic

operator specific features are

process

Module

implemented in this process as

Implements state event

service state event machines. These

machines for operator ser-

state event machines interact with

vices such as conference,

the generic call control state event

transfer, etc.

machines within the Call Control

Interact with call control

process to implement operator

function to implement oper-

specific features such as confer-

ator specific features

ence, blind transfer and third-party

call.

Net-

This process implements network

Called SubHeld Timer is

work

specific features such as Called

started when the called

Service

SubHeld Timer and Called

party releases. Call is not

Logic

SubAnswer Timer. Called SubHeld

actually released until the

Module

Timer and Called SubAnswer

timer expires. Before the

Timer are timers used during call

timer expires, the called

processing to hold the call for a

party can reconnect.

period of time.

Called SubAnswer Timer

defines the duration of

“ring No Answer” state

on the terminating end.

Prepaid

The Prepaid Service Logic Pro-

Prepaid timer logic. Timer

Service

gram implements the processing

started for the duration spe-

Logic

for prepaid service that resides

cified by the Prepaid ACP,

Pro-

within the switch controller

Active calls will be inter-

gram

preted at a configurable

time before the expiry of

this timer

Warning announcement is

initiated by this process

at the expiration of warning

timer

When a prepaid call termi-

nates, this process:

Cancels prepaid timer

Encodes Prepaid Call

Completion message

Interfaces with transmission

control protocol (TCP)

client process within the

switch service to send the

Prepaid Call Completion

message to Prepaid Service

Auto-

This process implements the trunk

Automatic Trunk Testing:

matic

test and product test requirements.

Recognize an incoming test

Trunk

call by specific pattern in

Routing

the called number field and

Service

route it to a pre-configured

Logic

test port. After this connec-

Pro-

tion, the Automatic Trunk

gram

Test equipment at either

end may exchange in-band

test tones to measure loss,

voice quality, echo etc.

Call Simulation and Pro-

duct Testing: Allow test

calls to be set up from test

trunks. The incoming test

call parameters such as

relevant SS7 fields and

other service parameters

such as card number, can

be set up via specific

screens on the System

Management Console.

Allow specific trunks to be

taken in and out of service

for testing

Allow test Operator Group

and assignments from Sys-

tem Management Center

(SMC) for Operator Train-

ing and product testing

The resource control function

208

includes two processes. The first is the system control process

424

, which is in charge of monitoring the states of a call and service-related resources. This system control process

424

is centrally aware of the resource state and general health of the switch controller. The system control process

424

is described in further detail in Table 8 below.

TABLE 8

System Control Module Functions

Resource

Function Preferred

Agents

Agent Registration

Dynamic Agent Status Update

Initiates switch download and configuration

when enough agents are logged in

Instructs the call queue process when an agent

becomes available

Programmable

Receives Programmable Switch Alarms and

Switch

updates the status of affected resources

Maintains the Programmable Switch Configuration

map

Initiates programmable switch resource “discovery”

process to synch up internal resource map with the

currently active state at the programmable switch

matrix

receives “resource delete” or “resource

update” messages from the system network

management protocol (SNMP) agent and if they are for

switch resources, instructs the programmable switch

support function to communicate to the switch matrix

receives “Get resource status” messages

and interacts with programmable switch support

function to initiate querying of the switch matrix

Switch

Maintains the Switch Controller state of operation,

Controller

including recovering:

a “Switch Controller Ready” message

from process manager which may initiate a switch

download and configuration operation

When enough agents have logged in,

instructs the programmable switch to accept incoming

calls via programmable switch support function

Monitors resources, initiates incoming call

throttling mechanism when the resource utilization

exceeds configured threshold

System Wide

Monitors system-wide abnormal events and reports

to System Management Console

Capacity Overload is monitored of the

capacity of the

Processor

Process table

Memory

Shared Memory

Inbound/Outbound trunks

IMT trunks, and

Operator position

Abnormal System Events are monitored

such as failure during

Initialization

Configuration

Activation, and

Run time faults/invalid events

Forced clearing of resources are monitored,

such as

Programmable switch channel purges,

and

Call Control function initiated purges

The second is the resource management process

422

. Exemplary switch controller resource management functionality includes management of both system-related resources such as message queues and a call data block table, as well as network resources such as the programmable switch matrices and agent resources. The resource management process

422

is described in further detail in copending U.S. patent application Ser. No. 09/096,939, filed Jun. 12, 1998, entitled “A System and Method for Resource Management” referenced above. A summary of resource management

422

functions are provided in Table 9 below.

TABLE 9

Resource Management Functions

Static and dynamic resource allocations

Read and Write access to resource data

Cross referencing between related resources

Data integrity

Create and manage message queues

Create and manage agent and group tables

Create and manage call-related information

Create and manage switch resources

The management interface function

412

includes two functional areas of monitoring control. The system monitoring functionality encompasses the generation of system alarms which allows a system management console (SMC) to monitor the status and run-time operation of the switch controller software. The management interface function

412

also includes the process manager

426

, which is responsible for initial startup and health of individual processes which make up the switch controller

112

. In addition, the management interface function

216

provides interfaces to the external management systems, including the system management system

226

, the force management system

228

, and the provisioning/configuration system

230

. Additional description of the processes within the management interface function

412

are provided in Table 10 below.

TABLE 10

Management Interface Function

Process

Description

Function

System

The Switch Controller System

Alarm monitoring

Man-

Management design includes the

Real Time monitoring

agement

two main functional areas: (1)

System Management

Inter-

monitoring and (2) control. The

Console

face

system monitoring functionality

SNMP Agent Data

encompasses the generation of

Processing

system alarms, which allow the

System Management Console to

monitor the status and run-time

operation of the Switch Controller

software modules. The Switch

Controller system monitoring

functionality is implemented using

several software interfaces and

system processes. The system

control functionality uses a system

network management protocol

(SNMP) agent design and

provides the system administrator

with the ability to control Switch

Controller resources during run-

time operation of the Switch

Controller.

Process

The Process Manager is

This is the parent process

Mana-

responsible for the initial startup

for all the other Switch

ger

and health of the individual

Controller processes. This

processes which make up the

process supports a UNIX

Switch Controller. Once the

Curses based HMI interface

Process Manager starts up, it

that is used to start up and

determines the initialization,

shutdown the Switch Con-

configuration, and activation order

troller. Commands are also

for each process within the Switch

supported to start up or

Controller. A configuration file is

shutdown any specific pro-

read and internal initialization is

cess within the Switch Con-

performed. After initialization is

troller. On startup, this pro-

complete, this process is ready to

cess reads its configuration

accept system operation

file that provides System

commands through a human

Information as well as indi-

machine interface (HMI) interface.

vidual process related

These commands are used to start

information.

up and shut-down the Switch

Controller. In addition, this

process also monitors the health of

the individual processes through a

heart-beat mechanism.

Force

This interface is used to monitor

Switch Controller provides

Man-

and manage the Agent population

the API to allow an external

agement

supported by the Switch

Force Management System

Inter-

Controller.

to query agent-related infor-

face

mation. The API set allows

down-load of statistical and

historical agent information

through a Force Manage-

ment specific interface.

Switch

The switch configuration utility is

The Switch Configuration

Con-

a stand-alone utility that provides

utility will provide the abil-

figura-

a user-friendly way of creating

ity to configure the follow-

tion

switch configuration files. This

ing entities/resources:

Utility

utility is not responsible for

Programmable switch load

changing the state of resources

file/system configuration

inside the programmable switch.

Timing Synchronization

Changing the state of resources is

Card Configurations

performed by the System

Span Configuration

Management Interface. The

Logical Span ID

output of this utility is Switch

Span framing parameters

Configuration file.

PCM encoding

configuration

DSP Configuration

Assignments

Tones

Announcement File

Download assignment

Conference Port

requirements/assignment

Channel/Trunk group

Configuration

CIC assignment -- Trunk

group assignment

PPL download/

configuration/assignment

Protocol/PPL assignments

Outsize/Insize

configuration

Answer supervision

configuration

Release supervision

configuration

SS7 Configuration

Links

Linksets

Routes

Stacks

The process manager

426

is the parent process for the other switch controller application program

402

processes. The process manager

426

is responsible for the initial start-up and shutdown of the switch controller

112

. Initial start-up is performed in part by reading a process manager configuration file. Provided below in Table 11 is the information included in the process manager

426

configuration file.

TABLE 11

Process Manager Configuration File

Type of Information

Parameters

System Information

Number of processes

List of Processes

Activation order

Process startup Retry limit and Retry timer

Shared memory size

Number of queues

Process Information

name of process

number of instances of the process to run

well-known message queue ID

heartbeat send interval

command line arguments

FIG. 5

is a block diagram of the ISN message interface

502

. The ISN message interface

502

illustrates the external interfaces of the switch controller

112

. The switch controller

112

communicates with the programmable switch

110

via TCP/IP over either a direct cable connection or a LAN (not shown). The switch controller

112

sends messages in an application programmer interface (API) messaging format that is specified by the programmable switch

110

vendor. For example, if an Excel programmable switch is used, then an Excel API is used. The Excel programmable switch API is described in a document entitled, “Excel API specification revision 5.0.”

The programmable switch

110

uses ISUP messaging in communications with the PSTN

106

. The ISUP messaging is part of SS7, and references a layer of SS7 messaging used to perform ISN type services. The switch controller

112

controls functions needed for call set-up including performing call processing and allocating facilities, such as programmable switch

110

channels and ports and ISN components

116

.

TABLE 12

ISUP Messages Sent Between the Programmable Switch

and the Switch Controller

Abbre-

viation

Message Name

Description

IAM

Initial Address

The Initial Address Message contains the

Message

digits identifying the called and calling

parties, the type of network connection

required, the characteristics of the calling

party (payphone, etc.), and the

characteristics of the call type (voice,

data, fax, etc.). For inbound calls, the

switch controller is mainly concerned

with the called and calling party numbers

which identify the product and operator

group required to support the call.

ACM

Address Complete

The Address Complete Message

Message

contains the backwards acknowledgment

through the network that the requested

facilities in the IAM have been provided

and where compromises were made

(satellite hops, etc.). Additionally, the

ACM indicates to the intermediate nodes

that voice should be provided in the

backwards direction of the call.

ANM

Answer Message

The Answer Message indicates that the

call has been answered by the called

party and indicates to the intermediate

nodes that two way voice path should be

provided.

REL

Release Message

The Release message indicates that one

party in the call has requested to release

the connection. Additionally, the REL

message may contain various cause

codes which indicate the reason for the

termination of the call (normal and many

possible abnormal conditions).

RLC

Release Complete

The Release Complete message indicates

that a request for REL is granted from

the previous nodes in the call and that

the resources assigned to the call shall be

released.

SUS

Suspend Message

The suspend message indicates

temporary suspension of an active call.

RES

Resume Message

Follows a suspend message to indicate

that suspended call is resumed.

The switch controller

112

communicates with each ISN component

116

via NSPP/UDP/IP over the ISN Ethernet LAN

214

. The NSPP messaging is used to implement an API referred to as transmission control (TC) messaging. The TC messages include messages needed for communication between the switch controller

112

and the various ISN components

116

to handle a call. For example, for a switch controller

112

to route a call to a particular ARU

204

port, the switch controller

112

sends a “Call Offered” TC message to that ARU

204

. The messages that are part of the TC API are included in the table below.

TABLE 13

TC Messages

Message initiating

component →

message reviewing

TC Message

component

Description

TC_Call

Switch Controller →

New Call offered to the

Offered

MTOC/ACP

platform

TC_Release

MTOC/ACP → Switch

To release a call leg

Controller

TC_Conference

MTOC/ACP → Switch

Conference in a terminating

Controller

party

TC_Call Park

MTOC/ACP → Switch

Park an active call and start

Controller

call park time

TC_Count

MTOC/ACP → Switch

Connect an originator and

Controller

terminator and drop off

operator

TC_Logon

MTOC/ACP → Switch

Logon an Operator

Controller

TC_Layoff

MTOC/ACP → Switch

Logoff an operator

Controller

TC_Update

MTOC/ACP → Switch

Update status of Operator

Controller

(Ready/Not Ready)

TC_On_Hold

MTOC → Switch

Hold the specified leg (on

Controller

and off hold)

TC_Off_Hold

MTOC → Switch

Take a leg off hold

Controller

TC_Answer

Switch/Controller →

Answer indication from the

ACP/MTOC

terminating party

TC_Observe

Supervisor Console →

To observe a specific

Switch Controller

operator

The Switch Controller communicates with system management

226

via NSPP/UDP/IP over the ISN Ethernet LAN

214

. A system management (SM) API is used for messaging. Either a customized protocol or a simple network management protocol (SNMP), which is an industry standard messaging protocol for network management, may be used.

The switch controller

112

communicates with force management

228

via NSPP/UDP/IP over the ISN Ethernet LAN

214

. A force management (FM) API that is specified by the vendor of the force management system

228

is used for messaging.

FIG. 6

illustrates a block diagram of the call control function

406

. The call control function

406

comprises a call state machine

604

and a signaling protocol state machine

602

. The call state machine

604

performs call processing by analyzing call processing information with respect to the current state as defined by the basic call state machine model. The call state machine

604

will be described in further detail with respect to FIG.

7

. The signaling protocol state machine

602

manages the states of resources used for calls, such as programmable switch

110

ports and trunks and ISN component

116

ports. State transitions are triggered by ISUP messages received from the PSTN

106

and from TC messages received from ISN components

116

.

Similar to the service logic programs which hide service-specific features, the protocol state machines

602

hide programmable switch

110

protocol state-logic. Hiding service-specific state logic and programmable switch protocol state logic enables the switch controller

112

to be a generic platform flexible to work with multiple programmable switch

110

vendors and easily modifiable to handle new services.

The protocol state machines

602

hide protocol specific details such as message details (e.g. transmit IAM) from the generic call state machine

604

. The protocol state machine

602

design allows multiple programmable switch

110

signaling protocols, such as Excel API and Summa

4

signaling protocol, to be supported by the same switch controller

112

. In addition, the protocol state machines

602

can accept trunks configured for different protocol variants e.g. UK ISUP, ANSI ISUP.

The call control function

406

has separate instances of the protocol state machines

602

for each resource, such as a programmable switch trunk. Because the protocol state event machines

602

are resource/trunk-specific, a call state machine

604

interacts with multiple protocol state machines

602

to control a call.

FIG. 7

is a block diagram of the call state machine

604

interface. The call state machine

604

interfaces with the programmable switch support function

404

(via the protocol state machine

602

not shown in

FIG. 7

) and the service control function

408

. The protocol state machine

602

and the service control function

408

hide all non-generic call processing functions from the call state machine

604

resulting in flexibility to handle non-generic call processing without changes to the call state machine

604

and with minimal isolated changes to other switch controller application

402

routines.

The call state machine

604

comprises two state machines for the originating and terminating legs of a call. A exemplary call is established between a calling party using calling device

104

a

and a receiving party using calling device

104

b

via an ISN

108

a

. The leg between the calling party using calling device

104

a

and ISN

108

a

is the originating leg. The leg between the ISN

108

a

and the receiving party using calling device

104

b

is the terminating leg. The call state machine

604

includes two separate state machines for the originating and terminating legs. The originating state machine

704

represents the state, referred to as the originating call state

708

a

,

708

b

,

708

c

,

708

d

, . . .

708

n

, of the originating leg of the call. The terminating state machine

706

represents the state, referred to as the terminating call state,

710

a

,

710

b

,

710

c

,

710

d

, . . .

710

n

, of the terminating leg of the call. A global state variable provides the state of a leg of a call. An originating global state variable tracks which of the originating call states

708

is associated with the originating leg of a call at a particular time. A terminating global state variable tracks which of the terminating call states

710

is associated with the terminating leg of a call at a particular time.

The separate originating and terminating state machine design allows for independent control of the originating and terminating legs. Functions such as splitting, merging and joining the originating and terminating legs of a call can be accommodated.) As a result, the separate originating and terminating state machine design provides a base for implementation of products requiring separate control of the originating and terminating legs such as multi-party conference and holding/waiting of calls. The separate originating and terminating state machine design also allows for the ability to perform call accounting and statistics per leg.

State changes occur because of detection point arming and processing resulting from a received event. Further description of state changes is provided with respect to

FIGS. 9A-9D

.

The call state machine

604

is modeled based on standard call states which are described in further detail in the International Telecommunications Union (ITU) specifications Q.1224, http://www.itu.ch/itudoc/itu-t/rec/q/q1000 up/q1218.html incorporated by reference herein. Originating call states

708

associated with the originating state machine

704

are described in further detail with respect to Table 14 below. Originating call states

708

indicating failure are described in further detail with respect to Table 15 below.

TABLE 14

Originating Call States

Originating Call State

Description

O_Null

Initial state for originating call model, allocates

internal resources

Authorize_Origination

—

Determines if originating Party has the author-

Attempt

ity to set up the call, based on the attributes

known so far

Collect_Information

Collects the routing and address digits required

to complete the call

Analyze_Information

Analyzes and/or translates the collected digits

according to the dialing plan to determine rout-

ing address and call types (e.g., a route list is

returned)

Select_Route

Interprets routing address and call

Authorize_Call_Setup

It verifies the authority of the calling party to

place this particular call

Send_Call

It sends an indication to set up a call to the

specified called party ID to the terminating

call model

O_Alerting

It waits for the terminating party to answer

O_Active

Connection is established between calling party

and called party. It collects accounting data.

Basic call cal be put on hold by service logic

O_Suspended

Basic call is suspended and waiting for

responses from terminating call or service logic

O_Exception

Exception event encountered

TABLE 15

Originating Call States Indicating Failure

Originating Call

State

Description

Origination

The incoming call cannot be serviced in the Switch

Denied

Controller. For example, the access code is not

recognized

Collect_timeout

The Collect Timeout event is detected when

enough information to process the call was not

received by the Switch Controller. For example,

IAM did not contain enough information to

originate a call

Invalid

Invalid information received (e.g., Wrong number

Information

format)

Authorize

Unable to select a route. Unable to determine a

Route Failure

correct route, no more routes on the route list

Active Failure

Abnormal condition during active call (e.g.,

Hardware failure)

Suspend Failure

Failure to successfully disconnect the call

Route Failure

e.g., No more routes left to try

Route Busy

Selected route is busy

Calling Party

Calling Party has been disconnected

Disconnect

Reconnect

Originating party goes offhook before the

re-answer timer expires

Terminating call states

710

associated with the terminating state machine

706

are described in further detail with respect to Table 16 below. Terminating call states

710

indicating failure are described in further detail with respect to Table 17 below.

TABLE 16

Terminating Call States

Terminating Call

State

Description

T_Null

Initial state of the Terminating Call Model

Authorize

Verification of authority to route the call to the

Termination

terminating access

Attempt

Select_Facility

Busy/Idle status of the terminating access is

determined

Present Call

Terminating resource informed of the incoming call

T_Alerting

Terminating party alerted. Waiting for answer by

terminating party

T_Active

The terminating party has accepted the call

T_Suspended

Terminating party disconnects

T_Exception

Exception event encountered

TABLE 17

Terminating Call States Indicating Failure

Terminating Call State

Description

Termination Denied

occurs when the authority to route the call to

the terminating user is denied; not applicable

for Day 1

Presentation Failure

e.g. C party termination failure

Call Rejected

not applicable for Day 1

Active Failure

abnormal events during active call (e.g.,

hardware failure)

Suspend Failure

failure to successfully disconnect the call

FIG. 8

is a flowchart of call state machine processing

802

. Call state machine processing

802

is described with respect to establishing an exemplary call between a calling party using calling device

104

a

and a receiving party using calling device

104

b

via ISN

108

a

. In order to establish the exemplary call, both an originating leg between calling device

104

a

and ISN

108

a

and a terminating leg between ISN

108

a

and calling device

104

b

must be established. In the exemplary call, an ISN component is immediately available and the call does not need to be queued. Call state machine processing

802

will be described with respect to relationships drawn between the switch controller application program

402

functions and call states shown in FIG.

7

.

In

806

, an ISUP message is sent from calling device

104

a

to the programmable switch

110

a

. The ISUP messages used to establish a call are described in further detail in Table 12 above.

In

808

, a programmable switch API message is sent from the programmable switch

110

a

to switch controller

112

a

. The programmable switch API message is received by the programmable switch support function

404

. The programmable switch API message varies based on the programmable switch vendor as discussed with respect to FIG.

5

. The protocol state machine

602

manages the programmable switch

110

specific details of call processing as discussed with respect to FIG.

6

.

In

810

, a first SCAPI message is sent from the programmable switch support function

404

to the call control function

406

. The receipt of the first SCAPI message is an event that is processed by the call control function

406

. The receipt of the first SCAPI message causes the originating global state variable to be set to originating call state 1

708

a.

In

812

, a second SCAPI message is sent from the call control function

406

to the service control function

408

as the result of processing associated with originating call state 1

708

a

. The second SCAPI message causes processing of the group select service logic program

416

to identify groups of ports connected to ISN components

116

of the type capable of processing the incoming call. A response to the second SCAPI message is received indicating that ISN component

116

a

is available to process the call. The response causes the originating global state variable to reflect that originating call state 3

708

c

is the state of the originating leg of the call.

In

814

, the ISN interface

414

is processed to send a TC message to an ISN component

116

a

that is available to process the incoming call. Processing of the call queue service logic program

418

is not needed because in the exemplary call, ISN component

116

a

was available immediately.

In

816

, a third SCAPI message is sent from the originating state machine

704

to the terminating state machine

706

to indicate that a terminating leg will be needed for an incoming call.

The third SCAPI message is the result of processing associated with originating call state 3

708

c

. The terminating global state variable reflects that terminating call state 2

710

b

is the state of the terminating leg of the call.

In

818

, a fourth SCAPI message is sent from the call control function

406

to other service logic programs

410

. The fourth SCAPI message is the result of processing associated with terminating call state 2

710

b

. The fourth SCAPI message inquires as to whether a TC message was received from ISN component

116

a

to establish a terminating leg for the call.

In

820

, a TC message is received from ISN component

116

a

by the service control function

408

requesting a terminating leg for the call. The TC message is processed by the ISN interface

414

. One or more of the other service logic programs

420

inquire the ISN interface

414

and determine that a TC message was received requesting a terminating leg for the call. The other service logic programs

420

that inquired respond to the fourth SCAPI message indicating that a TC message was received requesting a terminating leg for the call. The response to the fourth SCAPI message causes the terminating global state variable to reflect that terminating call state n

710

n

is the state of the terminating leg of the call.

In

822

, a fifth SCAPI message is sent from the call control function

406

to the programmable switch support function

404

to request a channel for the terminating leg of the call. The fifth SCAPI message results from processing associated with terminating call state n

710

n.

FIGS. 9A and 9B

illustrate two types of processing that cause call state changes. Call state changes may be based on dynamic detection point processing

902

or static detection point processing

906

. A detection point is a point in the processing of a call state at which the modifying features of the processing performed as a result of the call state are informed of an event the call control function

406

is about to process. The modifying features are features within the lines of code processed as a result of a call state that cause a state change.

A modifying feature may respond to notification of an event the call control function

406

is about to process with one of three actions: (1) trigger itself which will cause the call control function

406

to perform processing based on the event and the current state, (2) allow extension of call processing to a service logic program, or (3) override processing as a result of the incoming event, preempting processing that would be performed as a result of the incoming event and performing processing not associated with the incoming event. Therefore, processing is based on a current state of a call and an incoming event received unless the processing associated with an incoming event is preempted. An example of preempting processing of an incoming event is preempting call processing to reestablish a failed connection with a programmable switch

110

a.

A modifying feature triggers itself causing the call control function

406

to perform processing when the detection point is armed. A detection point is armed when a pointer or other notification means in software indicates that processing is to be performed. A detection point may be armed dynamically as shown in

FIG. 9A

or detection point processing may be based on static arming of the detection point as shown in FIG.

9

B.

FIG. 9A

illustrates dynamic detection point processing

902

. Dynamic detection point processing

902

occurs as the result of a detection point arming message

904

sent from a service logic program within the service control function

408

to the call control function

406

. The detection point arming message

904

informs the call control function

406

to arm a detection point during call set-up. The detection point arming message

904

provides a detection point identifier that can be analyzed using data stored in memory pointed to by a pointer associated with the detection point identifier.

Dynamic detection point processing

902

allows a detection point to be armed for only the particular call being processed. After call set-up is complete for the call, the detection point is no longer armed unless another detection point arming message

904

is sent. Dynamic detection point processing

902

allows service logic programs to cause the call control function

406

to perform functions for particular calls as directed by the service logic program.

FIG. 9B

illustrates static detection point processing

906

. Static detection point processing

906

is performed using configuration file

908

. Configuration file

908

is system wide. Detection points armed in the configuration file

908

are armed for all calls processed by the call control function

406

. The configuration file

908

stores arming information based on possible received events and current call states as indicated by a global state variable. When an event is received, an event handler is processed which handles initial processing needed to identify event and initiate further processing. The event handler includes an associated detection point identifier which identifies the current detection point and can be used to determine whether a detection point is armed.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, not limitation. Thus the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Number	Name	Date	Kind
4928304	Sakai	May 1990	A
5541917	Farris	Jul 1996	A
5544163	Madonna	Aug 1996	A
5673299	Fuller et al.	Sep 1997	A
5706437	Kirchner et al.	Jan 1998	A
5790173	Strauss et al.	Aug 1998	A
5825857	Reto et al.	Oct 1998	A
5826030	Herbert	Oct 1998	A
5912961	Taylor et al.	Jun 1999	A
5920621	Gottlieb	Jul 1999	A
5937042	Sofman	Aug 1999	A
6058181	Hebert	May 2000	A
6108337	Sherman et al.	Aug 2000	A
6188761	Dickerman et al.	Feb 2001	B1

Switch controller for a telecommunications network

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

CPC

US Classifications

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US

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Abstract

Description

Claims

US Referenced Citations (14)

Non-Patent Literature Citations (1)