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Introduction Intelligent Networks Advanced Intelligent Networks (AIN) Information Network Architecture Combining AIN and CTI Services The Intelligent Peripheral Intelligent Peripheral Services Software Architecture: Client, Router, Server The Application Results of AIN Focus
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Introduction The Intelligent Network (IN) has been under development since it was first introduced by Bell Communications Research in 1984. The goal of intelligent networking is to integrate the features and benefits on the new generation networks and to allow various types of information to pass through the telephone network without the need for special circuits. Data communications, Internet communications (using Internet Protocols), and voice networking have converged to provide a new and exciting set of services. These services revolve around the backbone of the Intelligent Network, which uses Signaling System 7 (SS7). Network architects envision one network capable of moving any form of information, regardless of the bandwidth. Data and voice calls will traverse this network the same way—making communication as simple as placing a traditional telephone call.
Intelligent Networks The Intelligent Networks consist of intelligent nodes (computer peripherals), each capable of processing and communicating with one another over low- to mid-speed data communications links. All nodes in the intelligent SS7 network are called signaling points that work with packet transmissions. A signaling point has the ability to do the following: 1. Read the packet address 2. Determine if the packet is for that node 3. Route the packet to another signaling point Signaling points provide access to the SS7 network and the various databases on the network. They also act as transfer points. More information will be explained in the SS7 chapter later. However, the switching network contains Service Switching Points (SSP) and provides the basic infrastructure needed to process calls and other related information. ■
The SSP provides the local access because it emerged as the Central Office. The SSP can also be other tandem points on the network or an ISDN interface for the Signaling Transfer Point (STP).
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■
The STP provides packet switching for message-based signaling protocols for use in the Intelligent Network (IN) and for the Service Control Point (SCP).
■
The SCP provides access to the IN database. The SCP is connected to a Service Management System (SMS).
■
SMS provides a human interface to the database, as well as the capability to update the database when needed.
■
Intelligent Peripherals provide resource management of devices such as voice announcers. Intelligent Peripherals are accessed by Signal Control Points when appropriate.
The Intelligent Network enables customers to tailor their specific service requirements within hours instead of days. It is expected that full Intelligent Network implementation will continue to evolve through the new millennium; however, the infrastructure has been laid and work continues. Some of the features available include the following 1. Find-me service 2. Follow-me service 3. Single (personal) number plans 4. Call routing service 5. Computer control service 6. Call pickup service Business is conducted by using a mix of public services, private networks, the Internet, wireless networks, and specialized carriers. Voice-processing requirements for a telephone switch were quite modest and could be satisfied by the limited announcement capabilities offered by the switch, usually as sequenced announcement of greetings, instructions, and terminating messages. No specialized service creation environment was required to develop and deploy these services. Complex voice-processing capabilities, such as central office-based voice mail were provided, but not as an integrated service of the switch. Complex voice-processing capabilities grew outside of the switching network in the form of interactive voice response systems, voice mail systems, automatic call distributors, and automated attendants. Over time, these systems embraced new technologies, including facsimile, speakerdependent and speaker-independent voice recognition, text-to-speech, and voice identification.
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Advanced Intelligent Networks (AIN) AIN is a collection of components performing together to deliver complex call switching and handling services. The Service Switching Point (SSP) is the central office that provides robust, call-switching capabilities. When switching decisions require complex call processing, the SSP relies on the Service Control Point (SCP), a subscriber database, and it executes service logic. The SSP uses SS7 signaling, specifically Transaction Capabilities Application Part (TCAP) messages, requesting the SCP to determine the best way to handle the call. The process supports telephony features, including 800 (888/877) and 900 calling, credit/debit card calling, call forwarding, and virtual private networks. AIN has promised an architecture that is amenable to rapid development and deployment of new services. How to maintain the stringent performance requirements of a central office service within this rapidly changing environment is a major challenge in the advancement of AIN. Intelligent Peripherals (IP) and Service Nodes (SN) are elements of the AIN and must be reliable to be deployed and used in the central office. Intelligent Peripherals work in cooperation with Service Control Points (SCP) to provide media services in support of call control. Service nodes combine the functions of the SCP and the IP. When viewed as point nodes in the network, these elements (IP and SN) are subject to failure and require redundant components and multiple communication paths. Software and procedures in support of central office reliability are also required. When switching decisions require complex voice processing services, the SCP cannot always provide all the required services to the SSP. The SCP cannot provide termination of voice circuits and play recorded messages, collect touch-tone input, or perform other voice processing services. The call must be redirected to an intelligent peripheral. The IP provides the voice processing services not available from the SCP. Advanced Intelligent Networks (AIN) provide more features and functions that are not provided by Intelligent Networks. Advanced Intelligent Network does not specify the features and services, but how they are used by end users. An essential component in AIN is the Service Creation Element (SCE). Today, service configuration and changes are handled by Telco personnel at end offices. The SCE specifies the software used to program end office switches. The single, most important change is through a
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Graphical User Interface (GUI). Over time, the SCE will reside at the users’ organization, allowing customers to tailor their services on an as-needed basis, without telephone company assistance. Some of these enhanced features available include the following items: ■
Calling name delivery
■
Call rejection
■
Call screening (visual or audio)
■
Call trace
■
Call trap
■
Personal ID numbers (pins)
■
Selective call acceptance
■
Selective call forwarding
■
Spoken caller identification
Some of these features are already available at certain COs, but they are not yet ubiquitous. Limitations to these services are based on the capabilities of end office switching equipment—service offerings and tariffs will not be consistent throughout telephone companies.
Information Network Architecture Information Network Architecture (INA) is still in development and viewed by many as the successor to AIN. However, there is considerable controversy over this view, and some believe that two architectures will eventually develop. AIN is designed to facilitate the voice network, whereas INA will manage the broadband network. The common belief is that INA will provide better utilities for managing new broadband services offered by telephone companies. Intelligent networking delivers computer and telephone integration capabilities inside the network. Two major market forces and architectural frameworks are merging to create the most explosive network services opportunities of the late ‘90s. Enterprise Computer Telephony Integration (CTI) applications and Advanced Intelligent Network (AIN) services are being integrated to provide an array of advanced carrier-delivered services. Some of the features that will be available to the executive or professional, especially telecommuters, include the following items:
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Virtual call centers
■
Consumer interactive applications
■
Centrex productivity enhancements
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Formal and informal call centers,
■
Virtual ACDs
Combining AIN and CTI Services The evolution of AIN and CTI services underpins the marriage of these two architectural frameworks. AIN has its roots in the Local Exchange Carriers’ (both ILEC and CLEC) and Inter Exchange Carriers’ (IEC) desire for vendor and switch independent network architectures. Improving the speed of service provisioning and delivering advanced network services is crucial to maintain a competitive posture. As early as 1986, Ameritech began proposing a concept called Feature Node Service Interface (FNSI). Through successive industry efforts, AIN emerged as a network standard in the early ‘90s. Figure 4-1 is the basic framework of the AIN architecture.
Figure 4-1 AIN architecture framework
STP
SS7
STP
SCP
SS7
IP or X.25
CO (SSP)
T1 SS7
SS7 or/IP
SMS
Intelligent Peripheral Legend: CO= LEC or CLEC Central Office SSP= Service Switching Point STP= Signal Transfer Point IP=Intelligent Peripheral /IP= Internet Protocol SMS= Service Management Subsystem
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Computer to Telephony Integration is a complement to AIN proposed by the PBX manufacturers. The end user’s desire: ■
Advanced applications
■
Faster feature delivery
■
Control and customization of applications all drove the development of the CTI interfaces
Using an external processor, custom applications are configured to enhance the functionality of a PBX, especially in an ACD environment. Figure 4-2 shows the basic connections in a CTI application. Both CTI and AIN use an external processor to deliver advanced complementary services to the switch. The switch controls call processing access to the external processor via an open interface. Both provide a GUI based Service Creation Environment (SCE) for rapid service and application configuration. Intelligent Peripherals (IPs) provide additional context information for call treatment. Integrated voice response units are the most widely deployed IPs. Reporting, billing interfaces, and real-time monitoring tools are available in both. With the introduction of the Intelligent Network (IN), these two technologies were brought together by necessity. Services rich in voice processing
Figure 4-2 Basic CTI application
PBX
Intelligent Processor
Digital Link or T1
T1
WAN
co
nk Tru ID D or
ACD T1
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content and requiring an abundance of digitized voice storage could no longer be created solely with the innate capabilities of the switch. The variety of service offerings, their complexity, and, in many cases, the requirement for multilanguage support, quickly outpaced the voice-processing capabilities and capacities of the switch. Voice-processing systems were integrated with switching systems to support these new services.
The Intelligent Peripheral The Intelligent Peripheral must provide voice circuit support and some mechanism for obtaining information about an incoming call. Several mechanisms are available for capturing call information including the following items: ■
ISUP signaling
■
ISDN signaling
■
In-band DTMF signaling
■
DTMF
BellCore developed transaction protocols to handle the call processing, using an 1129-protocol specification. The 1129 transaction is triggered when a call comes in. It is initiated with the delivery of a message from the IP to the SCP. Thereafter, the transaction continues with queries issued by the SCP and synchronous responses to these queries returned by the IP, reporting results of the requested action. The BellCore recommendations call for multiple intelligent peripherals within the network. Each is capable of working with multiple independent service control points via communication across multiple data paths. Each IP operates as though it is distributed across multiple host platforms interconnected by multiple LANs. Introducing IP into an AIN environment is a major expense, requiring significant investment in hardware, networking, and supporting software. The BellCore philosophy is to provide redundant components and data paths eliminating single points of failure wherever possible. However, many situations exist whereby an IP or SN provides a service, yet the service does not warrant redundant infrastructure. Therefore, a solution is required for the IP or SN to provide suitable reliability inherently.
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Intelligent Peripheral Services The Intelligent Peripheral (IP) must be capable of establishing and maintaining communication with multiple SCPs. Furthermore, it handles the following functions: ■
Encoding and decoding complex messages
■
Interpreting these messages
■
Performing the requested service. It must also be capable of switching functions including the following:
1. Call setup 2. Transfer 3. Call teardown 4. Detect call presentation and abandonment. 5. Process requests requiring service logic 6. Access databases. Finally, beyond the capabilities described in the 1129 interface specification, the IP needs support services such as logging, administration, alarm processing, statistics gathering and reporting, and database and network access. The IP falls into two categories of service: application processing and resource processing. The application processor supports the call processing logic and access to the databases and data networks. It initiates transactions, receives instructions, and reports success or failure of the action. The application processors also require connections to communication networks and hosts. An IP needs multiple data paths because it must be able to contact multiple hosts and must be able to survive the loss of a single communication pathway. It needs to communicate with SCPs to receive instructions and communicate with switching facilities in order to terminate circuits. It also needs to communicate with other network elements, such as the SMS (for provisioning), and to internal and external databases. This requires multiple data paths and alternate routing. The resource processor manages the switching, voice channel facilities, and media processing resources. The media processing normally requires multiple processors and disk storage to handle the media streams. It may also require switching, such as a time division multiplexer or external switches.
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These two elements are very different from each other. They perform different functions; consequently, they require very different hardware and software processing elements. The architecture for AIN with the SSP, SCP, and IP in place on the stack is shown in Figure 4-3.
Software Architecture: Client, Router, Server The objective is to build an intelligent peripheral in which application processors drive multiple resource processors. This requires software on the application processor capable of supporting the physical structure. A clientrouter-server scheme is used. The client includes the application, media processing logic, controls, manages the resources, and drives a state machine. The intelligent peripheral, driven by the 1129 message set, operates as a state machine. This state machine is driven by messages from the SCP and by trigger events from the network. The router handles message routing and session management functions. It makes decisions about how to route traffic and load-balance.
IP
Figure 4-3 AIN protocol stack
SSP INAP SSF SCF
Communications Link
INAP SRF
MACF
S C A F
ASEs (SCFSSF) TCAP SCCP MTP
SCP
SCE
INAP SSF SCF
MACF
I S U P
S C A F
ASEs (SCFSSF) TCAP SCCP MTP
SS7 LINK
MACFMACF
I S U P
S C A F
ASEs (SCFSSF) TCAP
S C A F
SCCP MTP
(SCFSSF) TCAP
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The servers support both local and remote devices. The local devices include local file systems, databases, and locally attached devices such as encryption boxes. The remote devices are networks and hosts. The remote servers must be multiple processor capable.
The Application The application must be capable of supporting real-time, online updates, which must be done without any disruption of service. The system administrator must be able to introduce new instructions and commands/responses without affecting service. On the fly changes to parameters, such as timers and retry limits, are necessary. The state machine itself must remain operational without call loss while the application logic is being changed.
Results of AIN It is possible to build intelligent peripherals in support of the AIN. These peripheral devices must be economical and reliable enough to operate in a central office environment. Multiple hardware elements are required. Communication paths must be redundant. Estimates are that by 2007, telephone industry spending will approximate $27 billion. Products and expenses supporting Advanced Intelligent Networks (AIN) will expand exponentially. Approximately $5 billion was spent on AIN products and services in 1998. Telephone industry spending on AIN will include Signaling Transfer Points (STP), Service Control Points (SCP), Service Switching Points (SSP), Intelligent Peripherals (IP), Service Creation Environments (SCE), and various hybrid products. Recent studies indicate that the demand for AIN features and functions will be driven by the following factors: 1. Demand for more customer control and services: Businesses are placing more strategic reliance on telecommunications. They need features and functions tailored to their specific needs. The number of functions and services required will be dictated by the lifestyle and business competitive environment of the end user. AIN is the only way to support such requirements. Services
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will have to be user-friendly and somewhat network-centric to meet the demands of the future user. 2. Greater geographical distribution and newer technologies: Future niche markets will probably emerge. They need to be widely available by the suppliers (LEC and IEC) to be effective and acceptable. AIN services must also become technology stable to support multiple vendor products and service on multiple switching systems. AIN-based services must find a way to work across carrier boundaries. 3. Mobility and mobile applications in a changing world: Businesses and personal use of communications support from cellular phones, voice mail, pagers, and e-mail are growing exponentially. The need to support a mobile user is now equally important. AIN-based services must cross vendor products and billing mechanisms to be effective. Wireless networks are among the fastest growing applications and services in the industry. The growth rate of 300% per year shows little sign of slowing. Personal Communications Services (PCS) networks are growing equally fast and demanding more services. Soon the AIN will have to support the single number for a user, regardless of where that user may reside. 4. Internet, Broadband, and Multimedia: A CIR1 report notes that most of the services that AIN is currently concerned with are narrowband and voice-oriented. However, the CIR report projects the belief that many of the services currently identified with AIN will migrate to the Internet. In addition, AIN concepts will increasingly be required for multimedia and broadband services. The market for the next few years around the world is shown in Figure 4-4
Focus Signaling System 7 (SS7) is an essential technology supporting and developing Integrated Services Digital Networks (ISDN), Intelligent Networks (IN),
1Communications Industry Reports is a research firm specializing in market research and analysis of the telecommunications industry.
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10000 Figure 4-4 Growth in AIN services around the world
8000 6000 4000 2000 0 1999 North America
2003 Western Europe
2007 Pacific Rim
Other
mobile (cellular) telephony, PCS and information systems, personal communications, and many other applications. Currently, this technology is being pursued by the telecommunication industry including carriers, large private networks, switch manufacturers, and an increasing number of software developers. The traditional methods of in-band signaling and other common channel signaling methods in the telecommunication networks have given way to an overlay network using a more capable, layered SS7 protocol. Although the primary function of SS7 is to handle call control-signaling requirements for voice and data transmission services, it can provide a number of advanced services by use of network databases. These include toll free and alternate billing, rerouting, virtual networks, and other highly sophisticated telecommunications services denoted by Intelligent Network services. Additionally, the transaction capability of the SS7 protocol makes it applicable to a broad range of new services dealing with remote operations. In cellular telephony, SS7 is used for mobility management and handover functions. Intelligent Network describes architecture designed to facilitate the implementation of highly sophisticated telecommunications services including: ■
Features and functions
■
Multivendor interworking
■
Differing priority services offered by fixed networks, mobile networks, and Personal Communications Systems
The new millennium will hold several benefits and service advantages unavailable in the past. These advantages will all be geared toward satisfying the changing needs and demands of the consuming public. As IN and AIN evolve, newer services will be introduced. The various new providers, such as
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Chapter 4 the CLECs and the CATV companies, will compete to meet the one-stop shopping demands of the customer. AIN will be one of the deciding factors steering consumers to the various providers. The first providers to implement the AIN features will have the edge over taking the customer base. The edge goes to the Incumbent LECs for now, because the infrastructure is theirs. However, as the new millennium rolls through, changes will occur. This is one of the critical components in being able to capture a niche in the market.
