1. Lecture-8/ T. Nouf Almujally
Telecommunications and Networks
Section 2 “Telecommunications Network Alternatives”
Chapter 6
Lecture-8/ T. Nouf Almujally 1

2. Telecommunications Network Alternatives
Telecommunications is a highly technical, rapidly changing field
Most business professionals don’t need detailed technical knowledge
However, understanding basic components and their characteristics is necessary
Can help you make informed decisions about telecommunications alternatives

3. Telecommunications Network Model
Terminals… Any input/output device that uses networks to transmit or receive data
Telecommunications processors… Devices that support data transmission, reception
Telecommunications channels… Media over which data are transmitted, received
Computers… All sizes and types
Telecommunications control software…
Controls telecommunications activities
Manages the functions of telecommunications networks
Includes network management programs of all kinds
Telecommunications monitors (mainframes)
Network operating systems (network servers)
Web browsers (microcomputers)
A telecommunications network is any arrangement where…
A sender transmits a message to a receiver
Over a channel
Consisting of some sort of medium

4. Key Telecommunications Network Component Categories
Terminals
Any input/output device that uses telecommunications networks to transmit or receive data
Example: Networked personal computers, network computers or information appliances.

5. Con. Telecommunications processors
Devices that support data transmission and reception between terminals and computers.
Control and support functions in telecommunications network.
Convert data from digital to analog and back
code and decode data
control the speed, accuracy, and efficiency of the communications flow between computers and terminals in a network.
Example: modems, switches, and routers

6. Con. Telecommunications channels Computers
Media over which data are transmitted and received
Example: copper wires, coaxial cables, microwave, cellular systems
Computers
All sizes and types of computers are interconnected by telecommunications networks.

7. Con. Telecommunications control software
Controls telecommunications activities
Manages the functions of telecommunications networks
Example: network management programs of all kinds such as,
Telecommunications monitors (mainframes)
Network operating systems (network servers)
Web browsers (microcomputers)

8. Types of Communications Networks
Wide Area
Local Area
Communication
Networks
Peer-to-Peer
Virtual Private
Client/Server

9. 1- Wide Area Network (WAN)
Telecommunications networks covering a large geographic area.
WANs are used by many multinational companies to transmit and receive information among their employees, customers, suppliers, and other organizations across cities, regions, countries, and the world.

10. 2- Local Area Network (LAN)
Connects computers within a limited physical area, such as an office, classroom, or building.
To communicate over the network:
each PC usually has a circuit board called “network interface card”
Most LANs use more powerful microcomputer with a large hard disk capacity, called “file server” or “network server”.
It contains a network operating system program that controls telecommunications and the use and the sharing of network resources.

11. Local Area Network (LAN)
LAN allows users to share hardware, software, and data resources.

12. 3- Virtual Private Network
VPN is used to establish secure intranets and extranets
The Internet is the main backbone network
Relies on network firewalls, encryption, and other security features
VPN = “pipe” travelling through the Internet
Creates a private network without the high cost of a separate proprietary connection
Used to establish secure intranets and extranets
The Internet is the main backbone network
Relies on network firewalls, encryption, and other security features to build a “pipe” through the Internet
Creates a private network without the high cost of a separate proprietary connection

13. Virtual Private Network
Used to establish secure intranets and extranets
The Internet is the main backbone network
Relies on network firewalls, encryption, and other security features to build a “pipe” through the Internet
Creates a private network without the high cost of a separate proprietary connection

14. 4- Client/Server Network
End user personal computers or networked computers
Servers
Used to manage the networks
Processing
Shared between the clients and servers
Sometimes called a two-tier architecture
Downsizing: Larger computer systems are being replaced with multiple client/server networks
Clients
End user personal computers or networked computers
Servers
Used to manage the networks
Processing
Shared between the clients and servers
Sometimes called a two-tier architecture
Larger computer systems are being replaced with multiple client/server networks

15. Client/Server Network
End user personal computers or networked computers
Servers
Used to manage the networks
Processing
Shared between the clients and servers
Sometimes called a two-tier architecture
Larger computer systems are being replaced with multiple client/server networks

16. Network Computing Called network centric
Views networks as the central computing resource of the organization
Thin clients provide a browser-based user interface for processing small application program called applets
Thin clients include:
Network computers
Net PCs
Other low-cost network devices or information appliances

17. Network Computing Application and database servers provide
The operating system
Application software
Applets
Databases
Database management software
Sometimes called a three-tier client/server model because it consists of:
Thin clients
Application servers
Database servers

18. Network Computing Application and database servers provide
The operating system
Application software
Applets
Databases
Database management software
Sometimes called a three-tier client/server model because it consists of
Thin clients
Application servers
Database servers

19. 5- Peer-to-Peer Networks
Central Server Architecture
P2P file-sharing software connects all PCs to a central server
The server sends the requesting PC a list of links to all active peers who have the file
Clicking a link connects the two PCs and automatically transfers the file to the requesting PC

20. Peer-to-Peer Networks
Pure Peer-to-Peer Architecture
No central directory or server
File-sharing software connects one PC to another online user
When you request a file, the software searches every online user, then sends you a list of active file names
Clicking a link automatically transfers the file from that user’s hard drive to yours

21. Peer-to-Peer Network Diagrams

22. Central Server Peer-to-Peer Networks
Advantages
Can better protect the integrity and security of the content and users of the network
Disadvantages
Directory server can be slowed or overwhelmed by too many users or technical problems

23. Pure Peer-to-Peer Networks
Disadvantages
Slow response times
bogus and corrupted files

24. Telecommunications Media
Telecommunications channels make use of a variety of telecommunications media.
These include:
Wired technologies: which physically link the devices in a network.
Wireless technologies: which uses microwave, radio waves or infrared light to transport digital communications without wires between communication devices.

25. Wired Technologies Twisted-Pair Wire Ordinary telephone wire
Copper wire is twisted into pairs
The most widely used medium for telecommunications, used in home and office telephone systems and many LANs and WANs.
Used in established communications networks throughout the world for both voice and data transmission.
Transmission speeds can range from 2 million bits per second (unshielded) to 100 million bits per second (shielded).

26. Twisted-Pair Wire Shielded Twisted–pair cable
Unshielded Twisted–pair cable

27. Wired Technologies Coaxial Cable
Sturdy copper or aluminum wire wrapped with spacers to insulate and protect it.
The cable’s cover minimize interference and distortion of the signals the cable carries.
They allow high speed data transmission from 200 to more than 500 million bits per second ( Mbps).
Used in high-service metropolitan areas, LANs and for short distance connections of computers and peripheral devices.

28. Wired Technologies Fiber-Optic Cable
One or more hair-thin filaments of glass fiber wrapped in a protective jacket.
Transmission rates are high (trillions of bits per second)
Fiber-optic are not affected by and do not generate electromagnetic radiation; therefore multiple fibers can be placed in the same cable.
Need less repeaters for signal retransmissions.
Expected to replace other communications media

29. The Problem of “The Last Mile”
Network providers use fiber optic cable as a communications backbone.
Houses connected to the backbone are wired with twisted pair (can’t handle the bandwidth provided by fiber)
Users don’t benefit from the faster, better technology.
Methods to solve this problem:
Using sophisticated technologies, only coaxial wire that originally put there.
Bypassing the old wired network completely and provide high speed services via a satellite or other wireless approach.
WiMax (still under development stages)

30. WiMax

31. Wireless Technologies
Terrestrial Microwave
Earthbound microwave systems transmit high-speed radio signals in a line-of-sight path between relay systems spaced about 30 miles apart
Antennas placed on top of buildings, towers, and mountain peaks.
Communications Satellites
Use microwave radio signals
Serve as relay stations
Earth stations beam signals to the satellites that amplify and retransmit the signals to other earth stations
Not suitable for interactive, real-time processing
Cellular and Pager Systems
Use radio technologies
Geographic areas divided into cells
Each cell has low-power transmitter or radio relay antenna
Computers & other communications processors coordinate/control transmissions to/from mobile users

32. Wireless Technologies
Terrestrial Microwave
Communications Satellites
Cellular,PCS telephone & Pager Systems

33. Wireless Technologies
Wireless LANS
Uses wireless radio-wave technology to connect PCs within an office or building
Wi-Fi is faster and less expensive than common wire-based LAN technologies
Bluetooth
Short-range wireless
Connects PCs to peripheral devices
Operating at 1 Mbps – range from 10 to 100 meters
Its a cable replacement technology
Wireless Web
Wireless access to the Internet is growing as more web-enabled information appliances appear.
Smart telephones, PDAs all are very thin clients in wireless networks
WAP (Wireless Application Protocol) is the foundation of wireless mobile Internet and Web Applications.

34. The Wireless Protocol (WAP)

35. Telecommunications Processors
Telecommunication Processors:
Perform a variety of support functions between the computers and other devices in a telecommunications network.
1- Modems:
the most common type of communications processor. Converts a digital signal to an analog frequency that can be transmitted over phone lines, then back into a digital signal (modulation and demodulation).
Come in several forms.
Support a variety of functions.
Transmission error control, faxing, and Automatic dialling and answering

36. Telecommunications Processors
Telecommunications networks are interconnected by special- purpose communications processors called :
Internetwork Processors: such as
Hub and Switch: makes connections between telecommunications circuits in a network. They provide automatic switching among connections called “ports” for shared access to a network’s resources.
Bridge: connect two or more LANs that use the same communications rules or protocol.
Router: intelligent communications processor that interconnects networks based on different protocols

37. Telecommunications Processors

38. Communications Processors
3. Multiplexer:
Allows a single communications channel to carry simultaneous data transmissions from many terminals.
Multiplexers work to increase the number of transmissions possible without increasing the number of physical data channels.

39. Telecommunications Software
Telecommunications and network management SW may reside in PCs, servers, mainframes, and communications processors.
Vital part of all telecommunications networks.
Used to manage network performance.
Servers rely on network operating systems like Novell Netware, UNIX, Microsoft Widows Servers.

40. Network Management Functions
Traffic Management
Manage network resources & traffic to avoid congestion, optimize service levels
Security
Provide authentication, encryption, firewall, auditing.
Network Monitoring
Troubleshoot & watch over the network, alerting administrators to problems
Capacity Planning
Survey network resources, traffic patterns, and users’ needs
Determine the best way to accommodate network needs as it grows and changes

41. Network Topologies Topology: The structure of a network Star Network
Ties end user computers to a central computer
Ring Network
Ties local computer processors together in a ring on a relatively equal basis
Bus Network
Local processors share the same communications channel
Mesh Networks
Uses direct communications lines to connect some or all of the computers to one another.

42. Network Topologies

43. Read from Chapter 6 (Section 2)