1. Chapter 7 Networks and Networking
Computers: Information Technology in Perspective, 11e Larry Long and Nancy Long
Chapter 7
Networks and Networking
Copyright Prentice Hall, Inc.

2. Copyright Prentice Hall, Inc.
Objectives
Once you have read and studied this chapter, you will have learned:
How the application of the concept of connectivity is affecting your life.
Alternatives and sources of data transmission services that have enabled the networking of our world.
The function and operation of data communications hardware.
The various kinds of network topologies, essential local area network concepts and terminology, and the scope and potential of home networking.
Copyright Prentice Hall, Inc.

3. Why this chapter is important to you!
Learning about data communications and networking before going online will save you both time and money
Learning about networks is not just for the office anymore; more and more homes are being networked everyday
Understanding about networks can save a lot of frustration
Copyright Prentice Hall, Inc.

4. Copyright Prentice Hall, Inc.
Our Wired World
Understanding information technology trends will help people cope with our increasingly wired society
People are knowledge workers by day
By night, people surf the Internet
Copyright Prentice Hall, Inc.

5. Copyright Prentice Hall, Inc.
Digital Convergence
Everything is becoming digitally compatible:
DVDs
Telephones
Televisions
Computers
Newspapers
College courses
Textbooks on CD-ROM
Banking/Finance
Copyright Prentice Hall, Inc.

6. Copyright Prentice Hall, Inc.
Connectivity
Connectivity means:
Accessing information from one department to the next
Sharing a printer
Communicating with suppliers
Sending a holiday newsletter via
Networking your home
Copyright Prentice Hall, Inc.

7. The Era of Cooperative Processing
Internally (for company resources) via
Intracompany networking
Intranets
Externally (for world competition) via
Intercompany networking
Business-to-business (B2B)
E-commerce (electronic commerce)
Extranets
VPS
Tunneling
Copyright Prentice Hall, Inc.

8. The Data Communications Channel
A communications channel is the medium through which digital information must pass
Same as line, link, or pipe
Requires special hardware that transmits the digital information between computers
Copyright Prentice Hall, Inc.

9. Transmission Media: Twisted-Pair Wire
Twisted-pair wire contains two insulated copper wires twisted around each other
One twisted-pair line provides POTS
Plain old telephone service: analog line that permits voice service
Another service is DSL
Digital subscriber line
Copyright Prentice Hall, Inc.

10. Transmission Media: Coaxial Cable
Coax: the cable in “cable television”
Minimum signal distortion
Has a very wide pipe
Hundreds of times faster than POTS
100 times faster than ISDN
Need a cable modem
Copyright Prentice Hall, Inc.

11. Transmission Media: Wireless Communication
Carries data via microwave or radio signals
Transmission is line-of-sight
Use transceivers/repeater stations
Satellites
Eliminates line-of-sight limitation
Geosynchronous orbit set at 22,300 miles above earth
Copyright Prentice Hall, Inc.

12. Transmission Media: Without Wires
Wireless transceivers between PCs
Alternative to running twisted-pair, coax, or fiber optics
Hooks into USB, PCI, or PCMCIA slot
Limited range about 50 feet
Use omnidirectional radio waves
Limited channel capacity
Copyright Prentice Hall, Inc.

13. Copyright Prentice Hall, Inc.
The Future of Wireless
Multichannel Multiport Distribution Service (MMDS)
Local Multiport Distribution Service (LMDS)
Wireless at fiber optic-level speeds
Will provide Internet service at 1 G bps
Copyright Prentice Hall, Inc.

14. Transmission Media: Fiber Optic Cable
Carries data as laser-generated pulses of light
Foundation transmission medium for Internet backbone
Better for data security
Future technology looks like very big “pipe”
Copyright Prentice Hall, Inc.

15. Copyright Prentice Hall, Inc.
Common Carriers
AT&T, MCI, Sprint, etc.
Private Line - Leased Line
Switched Line - Dialup Line
Copyright Prentice Hall, Inc.

16. Controlling Transmissions over Communications Channels
Communication protocols
Rules that govern the way data are transmitted
TCP/IP (Transmission Control Protocol/Internet) Protocol
Copyright Prentice Hall, Inc.

17. Asynchronous and Synchronous
Asynchronous Transmission
Low speed
Modem needed
Transmitted as needed
Start/stop bits used
Synchronous Transmission
High speed
Source and destination in “synch”
No start/stop bits needed
Copyright Prentice Hall, Inc.

18. Data Communications Hardware
Data communication hardware is used to transmit digital information
There are many devices that enable data communication
Concentrators
Hubs
Bridges
Routers
Brouters
NIC
Modems
And more…
Copyright Prentice Hall, Inc.

19. The Standard Telephone-Link Modem
Modulator-demodulator
Converts digital signals to analog signals for transmission over phone lines
Internal and external
Usually a voice/data/fax modem
Copyright Prentice Hall, Inc.

20. Copyright Prentice Hall, Inc.
Other Modems
Cable modem
Supports cable Internet
DSL modem
High-speed Internet connection using fiber-optic cable
Copyright Prentice Hall, Inc.

21. Network Interface Cards
Allows exchange of data via a LAN
Copyright Prentice Hall, Inc.

22. Copyright Prentice Hall, Inc.
Routers
Hardware and software used to ease the problems of linking incompatible networks
Routes messages to proper destinations
Backbone is a system of routers and transmission media that link computers
Copyright Prentice Hall, Inc.

23. Copyright Prentice Hall, Inc.
Terminals
Enables both input and output from a remote computer system
Dumb and smart terminals
Examples:
VDT (hospitals and airports)
Windows terminals
Telephone terminals
Special function (ATMs)
Copyright Prentice Hall, Inc.

24. Copyright Prentice Hall, Inc.
Networks
Networks are about sharing and communicating
Networks allow printers, data, Internet access, and more to be shared
Copyright Prentice Hall, Inc.

25. Copyright Prentice Hall, Inc.
Network Topologies
Network topology is a description of the possible physical connections within a network
It is a configuration of hardware and it shows which pairs of nodes can communicate
Copyright Prentice Hall, Inc.

26. Copyright Prentice Hall, Inc.
Network Topology - Star
Uses Category 5 cable (cat 6 is on the way)
Cat 5 cable uses an RJ-45 connector for the NIC card
Easy to install/not that expensive
Computers are concentrated into a star pattern using hubs or switches
Hubs broadcast data to all devices
Switches can be used instead of hubs
Switches can help segment data traffic but are more expensive
If there is a break in the cable it does not disturb the other computers
Copyright Prentice Hall, Inc.

27. Copyright Prentice Hall, Inc.
Network Topology - Ring
Uses different hardware
More expensive
Complex to install
Data is passed around the ring until it reaches its destination
Best at passing data with less collisions
Copyright Prentice Hall, Inc.

28. Copyright Prentice Hall, Inc.
Network Topology - Bus
Least expensive/easiest to setup
Uses coax cable
Computers are daisy chained together in a linear bus
Data packets are sent along the coax cables
All computers hear data sent out
A BNC connector is used for the NIC card
Copyright Prentice Hall, Inc.

29. Copyright Prentice Hall, Inc.
Types of Networks
Local Area Network (LAN)
Small network
Usually confined to a building or an office floor
Wide Area Network (WAN)
Two or more LANs connected together
The Internet is an example
Metropolitan Area Network (MAN)
Covers a large area, such as a city
Copyright Prentice Hall, Inc.

30. Copyright Prentice Hall, Inc.
LAN Overview
One node at a time can send
Token access method
Ethernet
Transmission media
Twisted-pair, coax, and fiber optic
LAN Servers
File server
Print server
Communications Server
Copyright Prentice Hall, Inc.

31. Copyright Prentice Hall, Inc.
LAN Software
Operating Systems
Peer-to-Peer LANs
LANs with dedicated servers
Client/Server
Applications Software
Shared software
Groupware
Networks on the Fly
Portable networks
Copyright Prentice Hall, Inc.

32. Copyright Prentice Hall, Inc.
Home Network
Home networks are becoming more popular
Home networks are typically peer-to-peer
A router keeps track of all the computers inside the home network
The computers are configured with fake IP addresses that allows them to communicate
Setup for a home computer is fairly easy
Copyright Prentice Hall, Inc.

33. Copyright Prentice Hall, Inc.
Summary
Our Wired World
The Data Communications Channel
Data Communications Hardware
Networks
Copyright Prentice Hall, Inc.