Signaling System No.7 Protocol Architecture And Sevices part 44

Summary The Intelligent Network is a continually-evolving model for distributed service processing in the telecommunications network. The models that represent call processing provide a generic interface for distributed control
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Signaling System No.7 Protocol Architecture And Sevices part 44SummaryThe Intelligent Network is a continually-evolving model for distributed serviceprocessing in the telecommunications network. The models that represent callprocessing provide a generic interface for distributed control, thereby allowingintelligence to move out of the SSP. The IN model also fits well into some nextgeneration telecom architectures, such as those built on IP-based softswitches.There are standards for delivering TCAP over the IP transport, such as the BellcoreGDI interface, which allows IN services to continue to work with little or nomodifications. Adjuncts already provide IP connections to IN SLPs, so themigration path to IP-based IN networks is occurring. A common theme among theproposed next-generation architectures is distribution of the functions performedby switching exchanges. The IN model fits into this structure by providing ageneric framework for both extending the PSTN and allowing it to interwork withthe new architectures.Of course, there are other intelligent endpoint architectures that providealternatives to the IN model, such as the Session Initiation Protocol (SIP). Thepoint of this chapter is not to debate the merits of which architecture is best but toprovide an understanding of the IN architecture, which so heavily depends on SS7signaling to function. < Day Day Up > < Day Day Up >Chapter 12. Cellular NetworksThis chapter introduces Global System for Mobile communications (GSM), whichis the most popular digital cellular network standard in terms of architecture,discusses interfaces and protocols, and concludes by presenting examples ofmobility management and call processing in the network. The protocols that arefound in GSM to perform these functions—namely, Base Station SubsystemApplication Part (BSSAP) and Mobile Application Part (MAP)—are applications(subsystems) that utilize the underlying functionality of the SS7 protocols andnetwork. This chapter aims to provide enough background on GSM cellularnetworks for you to understand the MAP that is used for mobility management andcall processing within the GSM network, which is discussed in Chapter 13, GSMand ANSI-41 Mobile Application Part (MAP).The European Telecommunication Standard Institute (ETSI) formulated GSM.Phase one of the GSM specifications was published in 1990, and the commercialoperation using the 900 Mhz range began in 1991. The same year, a derivative ofGSM, known as Digital Cellular System 1800 (DCS 1800), which translated GSMto the 1800 Mhz range, appeared. The United States adapted DCS 1800 into the1900 Mhz range and called it Personal Communication System 1900 (PCS 1900).By 1993, 36 GSM networks existed in 22 countries [119].Pre-GSM cellular networks are analog and vary from country to country—forexample, the United States still uses Advanced/American Mobile Phone Service(AMPS), and the UK used Total Access Communication System (TACS). Withthese older analog standards, it was impossible to have one phone work in morethan one country. In addition, because of the analog nature of the speech, qualitycould be relatively poor, and there were no provisions for supplementary services(such as call waiting). Although it is standardized in Europe, GSM is not just aEuropean standard. At the time of this writing, there are more than 509 GSMnetworks (including DCS 1800 and PCS 1900) operating in 182 countries aroundthe world, with 684.2 million subscribers [Source: GSM Association]. SeeAppendix I for a list of mobile networks by country.GSM has been released in phases. The following are the features of these phases:GSM Phase 1 (1992) Features • Call Forwarding • All Calls • No Answer • Engaged • Unreachable • Call Barring • Outgoing—Bar certain outgoing calls • Incoming—Bar certain incoming calls • Global roaming—–If you visit any other country or parts in an existing country with GSM, your cellular phone remains connected without having to change your number or perform any action.GSM Phase 2 (1995) Features • Short Message Service (SMS)— Allows you to send and receive text messages. • Multiparty Calling— Talk to five other parties and yourself at the same time. • Call Holding— Place a call on hold. • Calling Line Identity Service— This facility allows you to see the incoming callers telephone number on your handset before answering. • Advice of Charge— Allows you to keep track of call costs. • Cell Broadcast— Allows you to subscribe to local news channels. • Mobile Terminating Fax— Another number you are issued that can receive faxes. • Call Waiting— Notifies you of another call while you are on a call. • Mobile Data Services— Allows handsets to c ...