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introduction to telecommunication
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| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |___________________________________________________________________________
___________________________________________________________________________
| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 1 / 28 |
Introduction to Telecommunication Networks
Introduction
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 2 / 28 |
Introduction Outline
• Definition
• Needs and Applications
• Network Structure
• Players and Factors Driving Telecommunications
• Types of Networks
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 3 / 28 |
Definition
Telecommunication Network
• Infrastructure consisting of equipment & facilities to transfer information between users in different locations.– Telephone, TV broadcast, Internet, cellular, etc
• The exchange of information over a telecommunication network enables interaction at a distance nearly instantaneously.
Telecommunicationelectronic communication
at a distance
Networksystem of interconnected
electronic components/circuits
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 4 / 28 |
Needs and Applications
Why build a network?
• Networks enable services
• Communications networks typically provide a basic information transfer service
– Telephony: basic service is two-way exchange of voice signals• Other services enabled by this: voice messaging, fax, modem, ...
– Internet: basic service is transfer of information packets• Other services enabled by this: e-mail, web browsing, ecommerce, video
conferencing, ...
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 5 / 28 |
Needs and Applications
• Telecommunications involves
– Transporting information
– Relaying information
– Managing the transportation service
– Adding communications value
– Adding information value
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 6 / 28 |
Needs and Applications
• Gathering/Concentration
– bill payments / registration
– polling, voting, auctions
• Request/Reply
– catalogue ordering
– Web browsing
• Distribution– newspaper delivery
– television & radio broadcasting
– mass e-mail, including spam
• Two & Multi-way Interactive– telephone (& conferencing)
– video-on-demand
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 7 / 28 |
Needs and Applications
Users View
• Network provides a service to users via an interface that hides
details of network anatomy and functions from user.
• Interface provides friendly interrogation of user for control
information required by network.
• Interface presents message to user in a meaningful way.
• Interface provides network connection appropriate to service
requested.
– E.g. voice, video, data
• Interface provides address information which defines called-party.
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 8 / 28 |
Needs and Applications
• Users View
Network
Inte
rface
User 3
Interface
User 1 Inte
rface
User 2
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 9 / 28 |
Needs and Applications
Providers View
• Concerned with equipment and function that service the users requirements.
• Involves the details of the network’s anatomy.
– Physical network
– Directory mechanism
– Protocol
– Logical connection
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 10 / 28 |
Network Structure
• Network topology
Mesh Bus / Ring Star Multiple Star
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 13 / 28 |
Network Elements
• Transmission links
– Wire, cable, radio, satellite, fibre optics, …
• Nodes– Switches, routers, bridges, …
• Interfaces– NIC, …
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 14 / 28 |
Network Subsystems
A telecommunication network may be considered as a system
consisting of the following interacting subsystems:
– Transmission systems
• Subscriber loop
• Trunk
– Switching systems
• Local exchange
• Tandem exchange
– Signalling systems
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 15 / 28 |
Network Issues
• User– Provides source information
– User specifies service(s) required
• Network interface– Offers service
– Network interface implements service using transmission media
Information sourcesModulation and coding
Transmission Media, multiplexing, switching and signalling
ManagementQuality of service
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 16 / 28 |
Controlling Complexity
Enterprise architecture
Functional architecture
Technical architecture
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 17 / 28 |
Players and Factors Driving Telecommunications
End users
Service providers
Network operators
System suppliers
Component suppliers
Regulators
Financial backers
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 19 / 28 |
Economics for Success of a Network Service
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 20 / 28 |
Technology – Can it be built?
• Sustained improvements in technology allow complex networks and therefore new services
• Examples– microprocessor MIPs
– RAM memory
– storage: hard disk, CD-ROM, DVD, ...
– operating systems
– image & video compression
– digital signal processing
– wireless transmission
– transmission data rates
– network protocols
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 21 / 28 |
Long-Term Trends
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 22 / 28 |
Regulation – Is it allowed?
• Telephone originally monopoly
– Arose due to extremely high cost of infrastructure
– Profitable, predictable, slow to innovate
• Deregulation and break-up of monopolies
– competition in long distance telephone
– opening up of local telephone services
• Spectrum allocations
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 23 / 28 |
Market – Will it sell?
• New applications & services must have a market
– cellular telephony, fax transmission, Web browsing, e-commerce
• The network effect: usefulness of a service increases
with size of community
– Metcalfe's Law: usefulness is proportional to the square of the
number of users
• Economies of scale: per-user cost drops with increased
volume
– Cell phones, PDAs, PCs
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 24 / 28 |
Standards – Will it inter-operate?
• New technologies very costly and risky
• Standards allow players to share risk and benefits of a new market– Reduced cost of entry
– Interoperability and network effect
– Compete on innovation
• Example– 802.11 wireless LAN products
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 25 / 28 |
Network Standards
• Required due to:– Disparate applications using networks.
– Disparate user data rates / bandwidths.
Key Organisations:• International Telecommunications Union (ITU)
– Major international study and recommending body for telecommunications.
– Has several major committees. See the ITU-T (previously CCITT).
• International Organisation for Standardisation (ISO)– Voluntary organisation whose members are standards bodies of participating
nations.
• Tanzania Communications Regulatory Authority (TCRA)
• Institute of Electrical and Electronic Engineers (IEEE)
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 26 / 28 |
Quality of Service
• QoS: how happy the customers are:
– Grade of Service
– Loudness rating
– Dial tone delay
– Post dial delay
– Availability of service tone
– Correctness of billing
– Reasonable cost of service to customers
– Responsiveness to service request
– Responsiveness and courtesy of operators
– Time to install and add services
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 27 / 28 |
Different Types of Networks
• Internet Service Providers (ISPs).– Provide network service to customers (corporate or individual)
– ISPs can be international, national, regional, or local
– Organized as hierarchy: Tier 1, Tier 2, Tier 3
– Tier 1 networks form the backbone
• Corporate networks connect end-points in an organization.– Provide local connectivity and provide a path to an ISP
– Local-area network, dial-up through modem, ..
• Small networks supporting few users.– Home networks, hot spots, …
– Often use wireless for ease of deployment
| University of Dar es Salaam | Department of Electronics and Telecommunications Engineering |_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------| TE 413 Introduction to Telecommunication Networks | Christine Mwase | 01/10/2012 | Slide 28 / 28 |
Different Types of Networks
• Telephone network
• Data communication networks
• Integrated services digital networks
• Radio based networks
• Satellite networks
• Mobile communication networks
• Cable TV
• ...
