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Presentation on theme: "TELECOMMUNICATION TRANSMISSION AND SWITCHING SYSTEMS Lecture 01 Spring 2013 Instructor: Engr. Arifa Saher."— Presentation transcript:


2 Objectives To equip the students with skills and knowledge of the current and future telecommunication networks It assumes students have a background in Communication Systems Computer Communication Networks

3 Books Text: Telecommunication Switching, Traffic and Networks by J. E. Flood Reference: Telecommunication Switching Systems and Networks by V. S. Bagad

4 Marking Scheme 30% Mid Term Exam 12% Quiz 8% Assignment 50% Final Exam Theory Total 100% 75% A TTENDANCE IS MANDATORY FOR SITTING IN THE F INAL E XAM

5 Course Outline Development of Telecommunication Telecommunication Transmission Telecommunication Traffic Telecommunication Switching Systems Signaling techniques Public Switched Data networks (PSDN) Integrated Services Digital Network (ISDN)

6 Telecommunication Network A telecommunications network consists of Transmission systems Switching systems Stations

7 Transmission Systems Transmission (abbreviation: Tx): is the process of sending and propagating an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless. Transmission System: is a system that transmits a signal from one place to another. The signal can be an electrical, optical or radio signal. carries messages from an originating station to one or more distant stations. is engineered and installed in sufficient quantity to provide a quality of service compatible with the cost and expected benefits.

8 Transmission Systems Source Transmission Medium Destination The source may be a simple telephone microphone, keyboard The destination may be a simple telephone speaker, monitor SourceMedium Destination It can be a single electrical medium, or a cascade of electrical media

9 Switching systems Switching systems are an assembly of switching and control devices provided so that any station in a communications system may be connected as desired with any other station. To enable the transmission facilities to be shared, stations are connected to and reached through switching system nodes that are part of most telecommunications networks. Switching Systems act under built-in control to direct messages toward their ultimate destination or address.

10 High Availability Network Design Simplified Using Virtual Switching System

11 Review of Telecommunications

12 Development of Telecommunications 1837: Beginning of electrical communication, invention of Telegraph by Wheatstone and Morse 1876: Invention of Telephone by Alexander Graham Bell 1878: Opening of the first Telephone Exchange, at New Haven, Connecticut.

13 Global Telephony Trends 2008: 1.27 billion fixed line subscribers according to ITU At the end of 2011: Total mobile cellular subscriptions reached almost 6 billion corresponding to a global penetration of 86%. more than 1 billion mobile broadband subscriptions worldwide. 590 million fixed (wired) broadband subscriptions worldwide. 2.3 billion people were online.

14 Global ICT developments

15 Business of Telecommunication Involves various participants. These include: The public telecommunication Operators (PTO) Providers of Services that involve telecommunications Manufacturers of equipment and components Both hardware and software Financial investors Governments The users who must pay charges to cover the cost of providing the network so they are referred to as Subscribers or Customers

16 Telephony in action Two-way communication is required, on demand, between any pair of stations It must be possible for many conversations to take place at the same time How?

17 Network Structures User1User 2 User 3User 4 User 5 Ring Network N=1 Use r1 Use r 2 Use r 3 Use r 4 Mesh Network N=1/2n(n-1) User 1User 2User 3User 4User 5User 6User 7User 8 Bus Network N=1 Hub User 1 User 2User 3User 4User 5 Star Network N=n HUBHub1User1User2User3Hub2User4User5User6Hub3User7User8User9 Tree Network

18 Exchange Solution can be provided by connecting a line from each users station to the central switching center/telephone exchange a telephone exchange or telephone switch is a system of electronic components that connects telephone calls Area with a single exchangeArea with several exchanges

19 T L L L LL L L L L LL Junction Network Multi exchange area. L= Local Exchange T=Tandem Exchange Junction circuits Telecommunication networks hierarchy A National Public Switched Telecommunication Network (PSTN) consists of: Local network connects customers station to their local exchanges. These are also called subscribers distribution networks, customer access networks or the customer loop. Junction networks interconnects a group of local exchanges serving as area and a tandem or trunk exchange. The trunk network or toll network which provides long-distance circuits between local areas throughout the country.

20 International Gateway Exchange (Centre de Transit3) Satellite Links and Submarine Cables International Network Trunk Network Local Network National Tandem Exchanges (tertiary trunk switching centres) Regional Tandem Exchanges (Secondary trunk switching centres) Local Tandem Exchanges (Primary trunk switching centres) Local Exchanges Customer Lines National Telecommunication Network Junction Network Core Network PBX nodes

21 Elements of a Telecommunication Network Transmission System Switching System Signaling system Responsible for interchange of information Which are made up by interconnecting Customer nodes Switching nodes Transmission nodes Service nodes

22 Network Services Customers of a PTO may require different services which appear to require different networks. Examples include: Public Switched Telephone Network (PSTN) The Public Switched Telegraph Network (Telex) Private Networks for voice and data Radio networks providing mobile communication Public data networks (PDN) Special Service Networks

23 Network Services Continued.. Customers are connected to transmission bearer network at their local exchange via the local access network or local loop. The services provided over the telecommunication network can thus be divided into two categories: 1. Teleservices Provision of the service depends on particular terminal apparatus ( e.g. telephone or tele-printer). 2. Bearer Services Present the customer with transmission capacity that can be used for any desired function (e.g. private circuits) Transmission Bearer Network Visual PDN Telex PC PSTN Loop

24 Terminology North AmericanBritish Customers LoopLocal network Access Network Central officeExchange End OfficeLocal Exchange Class 5 Office Inter-office TrunkJunction JunctorTrunk Toll OfficeTrunk Exchange Toll networkTrunk Network

25 Assignment no. 1 Write a note, with the help of diagram/s, explaining the ISO reference model for Open System Interconnection.

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