Akıllı şebekelerin ve uygulanabilirliklerinin incelenmesi

Abstract

Bu çalışmada Akıllı şebekeler ve CCS7 işaretleşme sistemi üzerinde durulmuştur. ilk bölümde akıllı şebekelerin temel tası olan Numara-7 işaretleşme sistemi irdelenmiş, ardından Akıllı şebekelerin Türkiye'de uyarlanabilirliği araştırılmıştır. ikinci bölümde C7TU adı verilen test kolaylığı incelenmiş ve bu kolaylığa bazı eklemeler yapılmıştır. Son bölümde sayısal santralların yazılım yükünün hazırlanmasının incelemesi yapılmıştır.

Nowadays, the progress in telecommunications field and computer science is known from everybody. In this master thesis, todays most innovative work, the intelli_ gent network and Common Channel Signalling System CCS7 are investigated. The goal is not to rebuild the intel_ ligent network effectivelly. But giving the concepts of the intelligent network and its service provisioning is the first objective. The signalling system number seven is the indispensable material of the intelligent network. This thesis is constituted by three main chapters : The first chapter is the introduction. Signalling, signalling network, switching, switching systems, di_ gital exchanges are explained. After these concepts, the common channel signalling system number 7 is inves_ tigated. Through digital technology, signalling infor_ mat ion can be seperated from the transmission path and be processed in a computer. And whatever you can do with a computer, you can do with signalling. So CCS7 is the best suited and universally adopted signalling system for the intelligent network. The DMS digital exchanges used frequently in Turkey, are the adaptable switching nodes to the common channel signalling system number 7 (CCS7). In this chapter, implementation of CCS7 with these ex_ changes is made. STP ( Signal Transfer Point ), one of the basic stones of the common channel signalling, is used as a tandem (trunk to trunk) switching node in CCS7 backbone network. SCP ( Service Control Point ) is in_ troduced to handle the complexity of the service creation and distribution. After the investigation of the common channel signalling the IN { Intelligent Network ) is explained. The intelli_ gent network is a telecommunications network services control architecture. In essence, IN is a concept for network development and service provisioning, in a compe_ titive environment. It provides the framework of the introduction and growth of new network services. The technical features that the intelligent network architecture must provide are : - Network connection control intelligence at centralised nodes. This node is SCP (Service Control Point) at CCS7. - Network nodes which switch connections under the direc_ tion of the Service Control Point. These nodes are Ser_ vice Switching Points ( SSP ). - Standard network interfaces ( for example, CCS7 and ISDN ) at points such as the SCP at CCS7 -and SSP. These interfaces facilitate competition between suppliers of network and service products for multi-vendor environ_ ments. - Rapid and economic service creation capabilities ( such as customer programmabil i ty and program portability ) XX - The main advantages of the intelligent network can be summarised as follows : - Fast introduction capability of new services - Service programmabi lity - Customer control of network services - Cost-effective network implementation - Open standards solution, for multi-vendor environments - Powerful Service Management System for service creation administration, deployment and monitoring. A network with these attributes will contribute to the growth of the networks as well as actively encourage the development of new, competitive services. The additional functionality required for the intelligent network applications is all sotware based. Essentially, subscriber services provided by the intel_ ligent network are a customized set of features, which can be regarded as building blocks. Some examples of the services are : - Freephone : Charge-free calling or freephone eneables to assume the cost for calls that originate from their customers. - Televoting : The televoting service provides business subscribers in the intelligent netwo -rk with the capabi_ lity to pose questions via newspaper, radio, television and to advertise special voting numbers. Callers provide their answers by dialing the special number they wish to give which showes their vote. - Personel number : The Personel Number service assigns a distinct number to each subscribing user. Calls origi_ nating with the user's personal numbers as the called will be routed to a location designated by the user. - Teleconferencing : teleconferencing service provides multipoint capability that is accessible from the public network. The service allows subscribers to establish conference calls. - Private Virtual Network ( PVN ) : PVN provides the in_ terconnection between terminating nodes of the private network by using PSTN to achieve the same network fea tures and functions that have been provided by dedicated private lines. - Card calling : This service allows a subscriber to charge calls to a billing number associated with a per_ nal identification ( credit card ), thus enabling the te_ lephone administration to provide an alternative charging option to its subscribers. After investigating these features, two basic ser_ vices of the intelligent network taken up for the Turkish telephone network. These are Freephone (or green number service GNS or E-800 service ) and Automatic Calling Card service ACCS. The adaptation of these two services into the turkish telephone network is made. But the related software currently exists in North American base. All the DMS switcfe nodes work with an international software. The existing Turkish Network is examined at high level. - Xll - At the end of this chapter, DMS supernode. which is most advanced type of DMS switches, is fully investiga_ ted. The DMS supernode is the central side of the SONET DMS. S/DMS is the one the milestones to get the intelli_ gent network in Turkey. DMS Switches are the dominant exchanges in the Turkish telephone network. So the tele_ phone network points are the considered DMS switches in this study. In the second chapter, C7TU ( CCS7 test utility ) is described and some features added to this software by PROTEL ( DMSs software language ) programming. C7TU provides the ability to test CCS7 features, espe_ cially those for which the signalling messages are diffi_ cult to generate by any other methods. C7TU is intended as. a tool for the designers and testers in laboratory. The utility is designed to provide a facility to : - Send CCS7 messages to a signalling terminal, - Intercept and monitor messages between an MSB7 (Message Switch and Buffer No. 7) and its associated signalling terminals. - Allow messaging between two CCS7 networks on the same DMS using looped-back links, - Monitor messages within a Digital Trunk Controller, - Allow Digital Trunk Controller messages to loop back bypassing the IPML (Interperpheral Module Link) and MSB7. - Generate message traffic across the IPML, through the MSB7 and signalling terminals. In this chapter, C7TU is developped by adding the other signal isation message code to this utility. Some ISUP ( ISDN User Part ) messages codes, which are missing in this utility have been added to module soft_ ware code. These message codes are : - OLM ( Overload Message ) - CQM ( Circuit Group Query Message ) - CMRJ ( Call Modification Reject Message ) The final chapter is intended to build the CCS7 or other signalling type based software loads of the digital exchange. This process, named CC loadbuilding, is formed in two part: First is the hardest part. The goal is the building the software image of the DMS digital ex_ change in computer network environment. The second is loading this binary image to the DMS switching office and giving office specific dâtas to the switch. Total pro_ cess is named CC ( Central Complex ) Loadbuilding. Buil_ ding the sotware load of the digital exchange is consti_ tuted from various long processes. The design of the software projects is made by the designers. They make their updates to the PLS ( Program Library System ) lib_ rary. After they submit their code, the source code is downloaded to the unix workstations from the mainframe computer by the service virtual machines. Downloaded module sources form a compile set on workstation data- Xlll - files directory. This compile set is been compiled, and linked by other workstation server. The compile and link errors are fixed by the designers or loadbuilders. This is a critical section of the compile process because one or more modules can affected thousand other modules. DMS sofware language is PROTEL, the programs segments written in this language form the modules. These are the smallest units of the DMS exchange that can run processes by using data store. One DMS central complex load is consisted from approximately 14 000 modules. The group of modules, which have the same job, forms a subsystem. The subsystems are for example, related to metering, billing, call processing or signalling. A group of sub_ systems constitutes one Area. These areas can be part of the one global package, for example Mobile Telephone area. North American sofftware central complex of the DMS or Turkish specific software. At Netas CC loadbuilding process is made minimum twice per week. So packaging globally all areas and chosing the subsystems change di_ namically. After packaging the subsystems the compila_ tion is started. All the modules which are included in these subsystems are compiled and linked. After compila_ tion the binary formatted image formed these complied mo_ dules, is generated. The first step is completed. Loa_ ding of binary image to the office is the second step. After loading the binary image to the switch, all the modules have been contained. These modules must be initialised. This process is named as IPL ( Initial Program Loading ) and all the modules can be activated only by this method. This is the only way to define the modules to the digital switch. After the IPL process, many restart action must be do to renovate the dinamic datas. The next step is to introduce the specified datas into the switch tables. In DMS switch, all the constant datas are stored in form of matrix tables. After the datafill is completed, one image of this switch at build time must be dumped onto a scratch tape for the security, after image dumping, the software load is ready to use for testing. After the tests if this is a last load of the project, this image can be load to the PTTs DMS digital switches. The purpose is to add or substract subsystems from the switch using the flexibility of the CC Loadbuilding. So you can add new features to Turkish software load or remake a new package for the China software load for example. The result : The deployment of the IN and CCS7 into Turkish market is ready for the environment and will be ready for the Switching Software. But the network plan_ ning and different types of digital exchanges can form a - xiv problem to perform the Intelligent Network in Turkey. The software and signal isation adaptation of the Intelligent Network and CCS7, system and software testing and building the global switch load can be done at Netas. There are three kinds of digital exchange used in Turkish telephone network, These are DMS ( Northern Telecom ) System-12 ( Alcatel ), EWSD ( Siemens ) digital exchan_ ges. In the intelligent Network, all of them have to work together with the same signal isation. One other problem is making the common channel signalling link to all sides of the telephone network. Applicability of the : intelligent. network requires the new switching nodes, the new software and the adaptation of the different digital exchanges;' to work together.