chapter 4 networks 1 copyright john wiley & sons canada

CHAPTER 4Networks

1Copyright John Wiley & Sons Canada

Copyright John Wiley & Sons Canada 2

4.1 What Is a Computer Network?

4.2 Network Fundamentals

4.3 The Internet and the World Wide Web

4.4 Internet Network Applications

Chapter 4:

Networks


LEARNING OBJECTIVES

1. Define the term “computer network”, and compare and contrast the two major types of networks.

2. Describe the differences among the three types of wireline communications media, and discuss the main advantages and disadvantages of each type.


LEARNING OBJECTIVES (CONTINUED)

3. Differentiate between the Internet and the World Wide Web, and identify the most common methods for accessing the Internet.

4. Identify six major categories of network applications, provide an example of each, and explain how that application supports business functions.


OPENING CASE4.1 THE NETWORK NEUTRALITY WARS

The Problem

The CEO of Netflix was asked whether the Internet’s infrastructure can withstand the strain of his expanding business, which had more than 36 million subscribers worldwide as of mid-2013. He replied: “If there’s anything you’d want to bet on, it’s that technology will make bandwidth faster and cheaper.” That bet may not be as safe as it seems and the explosion of streaming video and mobile technologies in recent years is beginning to cause problems. The Internet was built to transmit content such as e-mails and web pages. In contrast, media items such as high-definition movies are magnitudes greater in size


THE NETWORK NEUTRALITY WARS

Solution– One possible solution is net neutrality. Network neutrality is the

concept that ISPs must allow customers equal access to content and applications, regardless of the source or nature of the content.



The Results– Most analysts expect that the heaviest data consumers

eventually will have to pay more, most likely in the form of tiered pricing plans. North Americans, however, have never experienced limits on the amount of data they upload and download. Nevertheless, wireless networks have already moved in the direction of these plans.



• Discussion– Why are telecommunications and cable companies are not in

favour of net neutrality?– Why are ISP’s in favour of net neutrality?


4.1 WHAT IS A COMPUTER NETWORK?

• Fundamental points about network computing:– They constantly exchange data with one another.– The exchange of data provide companies with a number of very

significant advantages.– This exchange can take place over any distance & over

networks of any size.


WHAT IS A COMPUTER NETWORK (CONTINUED)

• Bandwidth is the transmission capacity of a network; it is stated in bits per second.

• Broadband refers to network transmission capacities ranging from approximately 1 million bits per second (megabits/s) to as much as 20 megabits/s with fibre-to-the-home.


SIZE OF COMPUTER NETWORKS

• There are various types of computer networks, ranging from small to worldwide. They include (from smallest to largest):– personal area networks (PANs)– local area networks (LANs)– metropolitan area networks (MANs)– wide area networks (WANs) and the Internet


LOCAL AREA NETWORKS


WIDE AREA NETWORKS

• Wide area networks (WANs) are networks that cover large geographic areas.

• WANs typically connect multiple LANs. • WANs have large capacity, and they typically combine

multiple channels (for example, fibre-optic cables, microwave, and satellite).

• WANs also contain routers. A router is a communications processor that routes messages from a LAN to the Internet, across several connected LANs, or across a wide area network such as the Internet.


ENTERPRISE NETWORK


4.2 NETWORK FUNDAMENTALS

• Analog and Digital Signals• Communications Media and Channels• Twisted-Pair Wire• Coaxial Cable• Fibre-Optic Cables


ANALOG AND DIGITAL SIGNALS


MODEMS

• There are three types of modems:– dial-up modems– cable modems– DSL modems


COMMUNICATIONS MEDIA AND CHANNELS

1. Twisted-pair wire

2. Coaxial cable

3. Fibre optics


TRANSMISSION TECHNOLOGIES

• Digital subscriber line (DSL)• Asynchronous transfer mode (ATM)• Synchronous optical network (SONET)• T-carrier system• Network Protocols• Ethernet• Transmission Control Protocol/Internet Protocol

(TCP/IP)


THE FOUR LAYERS OF THE TCP/IP PROTOCOL


PACKET SWITCHING


TYPES OF NETWORK PROCESSING

• Client/server computing• Peer-to-peer processing


4.3 THE INTERNET AND THE WORLD WIDE WEB

• Accessing the Internet• Connecting via an On-line Service (ISP)• Connecting via Other Means (smart phones, ipads)


ACCESSING THE INTERNET

• Each computer on the Internet has an assigned address, called the Internet protocol (IP) address.

• IP addresses must be unique


ADDRESSES ON THE INTERNET

• Domain names– Top-level domain– Name of the organization– Name of the specific computer


ADDRESSES ON THE INTERNET

IPv432 bits 128 bits

IPv6


THE FUTURE OF THE INTERNET

• Many experts are now concerned that Internet users will experience brownouts (temporary unavailability or slower speeds) due to three factors:1. the increasing number of people who work on-line,

2. the soaring popularity of websites such as YouTube that require large amounts of bandwidth, and

3. the tremendous demand for high-definition television delivered over the Internet.


THE WORLD WIDE WEB

• The World Wide Web– Not the same thing as the Internet– Home page– Website– Uniform resource locator– Browser


BROWSER COMPETITION

• Companies are investing increasing amounts of resources in their browsers (Safari, Google Chrome, Mozilla Firefox, Opera , Microsoft Internet Explorer).

• A couple of developments are behind this trend. The first is Google, whose big plans for its Chrome browser forced Microsoft to pay more attention to its own browser, Internet Explorer (IE).

• The second factor was a decision by the European Union (EU). Starting in March 2010, the EU required computer manufacturers to offer European customers more freedom to choose their software.

• Regardless of which browser users select they should take into consideration issues of security and privacy.


4.4 INTERNET NETWORK APPLICATIONS

• Discovery• Communication• Collaboration• E-Learning and Distance Learning• Virtual Universities• Telecommuting


DISCOVERY

1. Search engines

2. Metasearch engines http://www.kartoo.com/

3. Publication of material in foreign languages

http://www.kartoo.com/


PORTALS

• Commercial (public) portals• Affinity portals• Mobile portals• Corporate portals• Industry wide portals


AFFINITY PORTAL (EXAMPLE)


COMMUNICATION

• Electronic mail (e-mail)• Web-based call centers (customer call center)• Electronic chat room• Voice• Unified


VOICE COMMUNICATION

• Two examples of Internet telephony (VoIP)– Skype– Vongae


COLLABORATION

• Work group• Work Flow• Virtual group (team)


COLLABORATION (CONTINUED)

• Virtual collaboration• Collaboration software• Electronic Teleconferencing• E-Learning and Distance Learning


CROWDSOURCING

• Crowdsourcing refers to outsourcing a task to an undefined, generally large group of people in the form of an open call.


SOFTWARE PRODUCTS SUPPORTING COLLABORATION

• Google Docs (http://docs.google.com) is a free, web-based word processor, spreadsheet, and presentation application.

• Microsoft’s SharePoint product (www.microsoft.com/Sharepoint/default.mspx) provides shared content with version control.

• IBM’s Lotus Quickr (www.ibm.com/lotus/quickr) product provides shared content with version control in the form of document directories with check-in and check-out features based on user privileges.

• Jive’s (www.jivesoftware.com) uses web collaboration and communication tools such as forums, wikis, and blogs to allow people to share content with version management, via discussion rooms, calendars, and to-do lists.

http://docs.google.com/

http://www.microsoft.com/Sharepoint/default.mspx

http://www.ibm.com/lotus/quickr

http://www.jivesoftware.com/


ELECTRONIC TELECONFERENCING

• The latest version of teleconferencing, telepresence systems, enable participants to seamlessly share data, voice, images, graphics, video, and animation electronically.

• See video on Cisco Magic

http://www.youtube.com/watch?v=rcfNC_x0VvE


E-LEARNING AND DISTANCE LEARNING

• E-Learning refers to learning supported by the Web.• Distance learning (DL) refers to any learning situation

in which teachers and students do not meet face-to-face.


BENEFITS OF E-LEARNING

• Online materials deliver high-quality, current content.• Students have the flexibility of learning from any place

at any time at their own pace.• Learning time generally is shorter, and more people can

be trained due to faster training time.• Training costs can be reduced.


DRAWBACKS OF E-LEARNING

• The purchase of additional multimedia equipment may be necessary.

• Students must be computer literate and may miss the face-to-face interaction with instructors.

• There are issues with assessing students’ work, as instructors really do not know who completed assignments.


VIRTUAL UNIVERSITIES

• Virtual universities are on-line universities in which students take classes from home or at an off-site location, via the Internet. A large number of existing universities offer on-line education of some form. Other universities offer limited on-line courses and degrees but use innovative teaching methods and multimedia support in the traditional classroom.


TELECOMMUTING

• Knowledge workers are being called the distributed workforce, or digital nomads. This group of highly prized workers is now able to work anywhere and anytime, a process called telecommuting.


TELECOMMUTING BENEFITS

• For Employees– Reduced stress, improved family life– Employment opportunities for single parents and persons with

disabilities

• For Employers– Increased productivity– Ability to retain skilled employees


TELECOMMUTING DISADVANTAGES

• For Employees– Feelings of isolation– Possible loss of fringe benefits– Lack of socialization– Lower pay (in some cases)– Potential for slower promotions

• For Employers– Difficulties in supervising work– Potential information security problems– Additional training costs


CHAPTER CLOSING

• A computer network is a system that connects computers via communications media so that data and information can be transmitted among them.

• There are three types of wireline communications media: twisted-pair, coaxial and fibre-optic cables

• The Internet is a global network of computer networks, using a common communications protocol, TCP/IP.

• The World Wide Web is a system that stores, retrieves, formats, and displays information accessible through a browser.

• There are six major categories of network applications: Discovery, Networks, E-learning, Collaboration, Virtual universities and Telecommuting

CopyrightCopyright © 2014 John Wiley & Sons Canada, Ltd. All rights reserved. Reproduction or translation of this work beyond that permitted by Access Copyright (the Canadian copyright licensing agency) is unlawful. Requests for further information should be addressed to the Permissions Department, John Wiley & Sons Canada, Ltd. The purchaser may make back-up copies for his or her own use only and not for distribution or resale. The author and the publisher assume no responsibility for errors, omissions, or damages caused by the use of these files or programs or from the use of the information contained herein.

Copyright John Wiley & Sons Canada

chapter 4 networks 1 copyright john wiley & sons canada

Documents

network computing

network fundamentals

term computer network

size slide

favour of net neutrality

wireless networks

exchange of data

major types of networks