1. Telecommunications and Networks
Chapter 6
Telecommunications and Networks

2. Learning Objectives Understand the concept of a network.
Apply Metcalfe’s law in understanding the value of a network.
Identify several major developments and trends in the industries, technologies, and business applications of telecommunications and Internet technologies.
Provide examples of the business value of Internet, intranet, and extranet applications.

3. Learning Objectives
Identify the basic components, functions, and types of telecommunications networks used in business.
Explain the functions of major components of telecommunications network hardware, software, media, and services.
Explain the concept of client/server networking.
Understand the two forms of peer-to-peer networking.
Explain the difference between digital and analog signals.

4. Learning Objectives
Identify the various transmission media and topologies used in telecommunications networks.
Understand the fundamentals of wireless network technologies.
Explain the concepts behind TCP/IP.
Understand the seven layers of the OSI network model.

5. Network Concepts Network
An interconnected chain, group or system
Number of possible connections on a network is N * (N-1) / 2
Where N = number of nodes (points of connections on the network)
Example, if there are 10 computers on a network, there are 10 * 9 / 2 = 45 possible connections

6. Trends in Telecommunications

7. Digital Network Technologies
Rapid change from analog to digital network technologies
Analog: voice-oriented transmission, sound waves
Digital: discrete pulse transmission
Digital allows:
Higher transmission speed
Larger amounts of information
Greater economy
Lower error rates
Multiple forms of communications on same circuit

8. Internet2 Next generation of the Internet High-performance network
In use at several hundred universities, scientific institutions, communications corporations
Internet2 may never replace the Internet. May remain a scientific and government network.

9. Business Value of Telecommunication Networks

10. The Internet 2.27 billion users (2012) No central computer system
No governing body
No one owns it
With all these users, Metcalfe’s law suggests the possible connections are extraordinary

11. Internet Service Provider
ISP
A company that specializes in providing easy access to the Internet
For a monthly fee, you get software, user name, password and access
ISPs are connect to one another through network access points

12. Using the Internet for business

13. Business value of the Internet

14. An Intranet A network inside an organization
That uses Internet technologies (such as Web browsers and servers, TCP/IP protocols, HTML, etc.)
To provide an Internet-like environment within the organization
For information sharing, communications, collaboration and support of business processes
Protected by security measures
Can be accessed by authorized users through the Internet

15. Extranet Network links that use Internet technologies
To connect the Intranet of a business
With the Intranets of its customers, suppliers or other business partners

16. Extranet Uses

17. Wide Area Network (WAN)
Telecommunications network that covers a large geographic area
Source: Courtesy of Cisco Systems Inc.

18. Local Area Network (LAN)
Connect computers within a limited physical area such as an office, classroom, or building

19. Virtual Private Networks (VPN)
A secure network that uses the Internet as its backbone but relies on firewalls, encryption and other security
A pipe traveling through the Internet

20. VPN

21. Client/Server networks
Clients: End user personal computers or networked computers
Interconnected by LANs
Servers: manage networks
Processing shared between clients and servers
Two tiered client server includes just client and server
Maybe connected to optional super servers

22. Client/Server Network

23. Network Computing
Networks are the central computing resource of the organization
Thin clients: network computers and other clients provide a browser-based user interface
Thin client means that very little processing is done on the client. Most the processing is done on the server.
Three-tier model includes thin clients, application servers and database servers

24. Peer-to-peer networks
Networks that connect from one PC to another PC
Common use is the downloading and trading of files
With a central server architecture, P2P file-sharing software connects your PC to a central server that contains a directory of all the other users in the network. When you request a file, the server searches the directory for any other users who have that file and are online. You click on list and make the P2P connection.
Napster used this architecture.
Pure P2P has no central directory or server.

25. Peer-to-Peer Network

26. Telecommunications Media
Twisted-pair wire:
Ordinary telephone wire
Copper wire twisted into pairs
Twisted pair transmission speeds range from 2 million bits per second (unshielded) to 100 million bits (shielded)
Coaxial cable from 200 million bits to over 500 million bits per second
Fiber optic cable as high as trillions of bits per second. Uses light elements instead of electricity
Source: Phil Degginger/Getty Images.

27. Telecommunications Media
Coaxial cable:
Sturdy copper or aluminum wire wrapped with spacers to insulate and protect it
Twisted pair transmission speeds range from 2 million bits per second (unshielded) to 100 million bits (shielded)
Coaxial cable from 200 million bits to over 500 million bits per second
Fiber optic cable as high as trillions of bits per second. Uses light elements instead of electricity
Source: Ryan McVay/Getty Images.

28. Telecommunications Media
Fiber-optic cable:
One or more hair-thin filaments of glass fiber wrapped in a protective jacket
Twisted pair transmission speeds range from 2 million bits per second (unshielded) to 100 million bits (shielded)
Coaxial cable from 200 million bits to over 500 million bits per second
Fiber optic cable as high as trillions of bits per second. Uses light elements instead of electricity
Source: CMCD/Getty Images.

29. Problem of “The Last Mile”
Network providers use fiber optic to provide backbone
But houses are connected to the backbone via twisted-pair
Cannot get the benefit of the faster, better technology
Need to connect houses with a higher-speed technology. One solution is cable connection.
Another solution is to skip the wires and use satellite or wireless.

30. Wireless Technologies
Terrestrial microwave
Earthbound microwave systems that transmit high-speed radio signals in a line-of-sight path
Between relay systems spaced approximately 30-miles apart
Communications satellites
Satellite serves as relay stations for communications signals
Uses microwave radio signals

31. Wireless Technologies
Cellular and PCS telephone and pager systems
Divide the geographic area into small areas or cells
Each cell has transmitter or radio relay antenna to send message from one cell to another
Wireless LANs
Radio signals within an office or building
Connect PCs to networks
Bluetooth
Short-range wireless technology
To connect PC to peripherals such as printer

32. Wireless Web Connect portable communications devices to the Internet
Very thin client such as telephone, pager, PDA
WAP: wireless application protocol
WML: wireless markup language

33. Internetwork Processors
Switch – makes connections between telecommunications circuits in a network
Router – intelligent communications processor that interconnects networks based on different protocols
Hub – a port switching communications processor
Gateway – connects networks using different communications architectures
Multiplexer - Allows a single communications channel to carry simultaneous data transmissions from many terminals

34. Network management functions
Traffic Management – manage network resources and traffic to avoid congestion and optimize service levels to users
Security – provide authentication, encryption, firewall, auditing and enforcement
Network Monitoring – troubleshoot and watch over the network, informing network administrators of potential problems before they occur
Capacity Planning – survey network resources and traffic patterns and users’ needs to determine how best to accommodate the needs of the network as it grows and changes

35. Network Topologies Topology: structure of a network
Star: ties end user computers to a central computer
Ring: ties local computer processors together in a ring on a relatively equal basis
Bus: local processors share the same communications channel

36. Network Topologies

37. Network Architectures & Protocols
Protocol: standard set of rules and procedures for the control of communications in a network
Transmission Control Protocol / Internet Protocol (TCP/IP)
A five layer telecommunications protocol used by the Internet

38. Internet Telephony
Using an Internet connection to pass voice data using IP
Voice over IP (VoIP)
Skips standard long-distance phone charges

39. View How the Internet Works Video