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1. Telecommunication Transmission and Switching Systems Lecture 01 Spring 2013 Instructor: Engr. ArifaSaher

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 75% Attendance is mandatory for sitting in the Final Exam

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 • The source may be a simple telephone microphone, keyboard • The destination may be a simple telephone speaker, monitor • 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 http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps9336/images/prod_qas0900aecd806ed74b-2.jpg

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 2001-2011

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 User1 User 4 User 2 User 3 Ring Network N=1 Bus Network N=1 Mesh Network N=1/2n(n-1) Tree Network Star Network N=n

18. Exchange • Solution can be provided by connecting a line from each user’s 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 exchange Area with several exchanges

19. 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. L L L L L T L L L Junction circuits L Junction Network Multi exchange area. L= Local Exchange T=Tandem Exchange L L

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

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: • Teleservices • Provision of the service depends on particular terminal apparatus ( e.g. telephone or tele-printer). • Bearer Services • Present the customer with transmission capacity that can be used for any desired function (e.g. private circuits) Visual PDN Telex PC PSTN Transmission Bearer Network Loop

24. Terminology

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