Networking Applications

7/27/2019 Networking Applications

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UNIT 4 NETWORKING APPLICATIONSLESSON 10 INTRODUCTION TO COMPUTER NETWORK COMPUTER THREATS

LESSON 11 TYPES OF NETWORK

LESSON 12 NETWORK HARDWARE


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LESSON 10 INTRODUCTION TO COMPUTER NETWORK

TABLE OF CONTENTS:

10.0 OBJECTIVES

10.1 INTRODUCTION

10.2 CONCLUSION

10.3 POSSIBLEANSWERS TO SELF-CHECK QUESTIONS

10.4 TERMINAL QUESTIONS

10.5 FURTHER READING

10.6 GLOSSARY


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BBM 101 Unit 4, Lesson 10

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10.INTRODUCTION TO COMPUTER NETWORK

A computer network is a collection of computers and devices connected toeach other. The network allows computers to communicate with each other andshare resources and information.

10.0 Objectives

After going through this lesson, you will be able to

What is a computer network and its advantage

ISO Structure of network

10.1 Introduction

A network is a group of connected computers that allows people to shareinformation and equipment. Computers connected to a network can share computerresources, such as printer. A network also allows you to easily share informationwith others. Sharing information and resources is especially useful when people on anetwork are working together on a project.

The advantages of network are as follows:

1. Exchange e-mail: You can exchange e-mail messages with other people onnetwork. Large companies often setup a mail server that only people on the

Figure 10.1 Computer Networking


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network can use, which offers a faster, more secure and more flexible e-mailservice.

2. Remote access: Having your own network allows greater mobility whilemaintaining the same level of productivity. With remote access in place, users

are able to access the same files, data, and messages even when they're notin the office. This access can even be given to mobile handheld devices.

3. File sharing: A network makes it easy for everyone to access the same fileand prevents people from accidentally creating different versions.

4. Exchange Instant Messages: Networks allow you to send messages that willinstantly appear on other computer screens.

5. Collaboration: Networks make it easy to collaborate on a project. You can usesoftware on a network to help schedule meetings, have more than one person

work on same document and much more.

6. Share an Internet connection: Compute on a network can share a singleinternet connection.

7. Videoconferencing: Networks allow you to have face-to-face conversationswith other people on the network located across the city or country.

Data flow or communication can be divided into seven logical layers calledOSI layers model that was developed by Intel and Xerox Corporation and wasstandardized by ISO.

1. Application layer

2. Presentation layer

3. Session layer

4. Transport layer

5. Network layer

6. Data Link layer

a. Media access control sub-layer

b. Logical link control sub-layer

7. Physical layer

A common communication language is used by the computers and thecommunication devices is known as protocols. The most commonly used andpopular protocol on the internet and in the home and other networks is calledTCP/IP. TCP/IP is not a single protocol but it is a suite of several protocols. Acomputer network can be a wired or wireless and TCP/IP protocol can work both in

types of a network.


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Self-check Questions

1. The data communication can be divided into _____ layers.

2. The commonly used protocol on the networks is called ________

10.2 Conclusion

In this lesson you have studied the concept of computer network and itsadvantages.

10.3 Possible Answers to Self-check Questions

1. 7

2. TCP/IP

10.4 Terminal Questions

1. What is Network? Explain its Advantages.

10.5 Further Reading

1. Peter Norton, Peter Norton's Introduction To Computers - Sixth Edition,McGraw Hill, ISBN: 0-07-297890-2

2. Andrew S. Tanenbaum, Computer Networks

3. L Donald, MCSE JumpStart: Computer and Network Basics

10.6 Glossary

1. Internet (Net) the worldwide network ofcomputers originally set up by the USDepartment of Defense in the late 1960s.Called ARPANET (Advanced ResearchProjects Agency Network), it was designed tofunction as a continuing method ofcommunication. In time, it was used as a

means of communication among universityscholars throughout the United States. It


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eventually evolved into the popular electronicforum for international communication by wayof interactive discussion, email, commercialWebsites, entertainment and much more. Theterm internet written with a lower case i

indicates a local computer network.

2. Internet Explorer(IE, MIE) Microsofts popularWeb browser, available for both PC andMacintosh. In addition to offering an emailprogram, Internet Explorer allows users to viewWeb pages. See also Explorer.

3. Internet Service Provider (ISP) a companythat provides Internet service to a customer.Usually, in exchange for a fee, the company

provides access to the Internet and one ormore email accounts. Many providers offerunlimited monthly usage for a flat fee of around$20. It is important to use an ISP that providesa local dial-up number, otherwise the user ischarged long distance rates while connected tothe Internet. It has become increasingly popularfor some ISPs to offer free access to theInternet. Under this arrangement, the providerdisplays some type of advertising on the usersscreen (which can not be removed) for the

duration of the online session.

4. Intranet A group of computers, oftenbelonging to a company or some other privateenterprise, linked together for the purpose ofcommunications. The intranet may functionusing the Internet as a means of transmittingdata or as a completely isolated network. Aspart of the Internet, a particular intranet mightuse security measures such as passwords, keycodes, and firewalls to keep communications

exclusive to that organization.


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LESSON 11 TYPES OF NETWORK

TABLE OF CONTENTS:

11.0 OBJECTIVES

11.1 INTRODUCTION

11.2 CLASSIFICATION OF NETWORK

11.3 TYPES OF NETWORK HARDWARE

11.4 CONCLUSION




11.8 GLOSSARY


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BBW 101 Unit 4, Lesson 11

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11.TYPES OF NETWORK


11.0 Objectives


Classify computer network

Describe types of network

11.1 Introduction

A network is a group of connected computers that allows people to shareinformation and equipment.

11.2 Classi f icat ion of NetworkThe following list presents categories used for classifying networks.

1. Connection method

Computer networks can also be classified according to the hardware andsoftware technology that is used to interconnect the individual devices in thenetwork, such as Optical fiber, Ethernet, Wireless LAN, HomePNA, Power linecommunication or G.hn.

Ethernet uses physical wiring to connect devices. Frequently deployed devicesinclude hubs, switches, bridges and/or routers.

Wireless LAN technology is designed to connect devices without wiring. Thesedevices use radio waves or infrared signals as a transmission medium.

ITU-T G.hn technology uses existing home wiring (coaxial cable, phone lines andpower lines) to create a high-speed (up to 1 Gigabit/s) local area network.

Power line communication or power line carrier (PLC), is a system for carrying dataon a conductor also used for electric power transmission.


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The HomePNA Alliance is an incorporated non-profit industry association ofcompanies that develops and standardizes technology for home networking over theexisting coaxial cables and phone wires within the home.

2. Scale

Networks are often classified as Local Area Network (LAN), Wide AreaNetwork (WAN), Metropolitan Area Network (MAN), Personal Area Network (PAN),Virtual Private Network (VPN), Campus Area Network (CAN), Storage Area Network(SAN), etc. depending on their scale, scope and purpose. Usage, trust levels andaccess rights often differ between these types of network - for example, LANs tendto be designed for internal use by an organization's internal systems and employeesin individual physical locations (such as a building), while WANs may connectphysically separate parts of an organization to each other and may includeconnections to third parties.

3. Functional relationship (network architecture)

Computer networks may be classified according to the functional relationshipswhich exist among the elements of the network, e.g., Active Networking, Client-server and Peer-to-peer (workgroup) architecture.

a. Active networking

Active networking is a communication pattern that allows packets flowingthrough a telecommunications network to dynamically modify the operationof the network.

b. Client-server Network

The client-server software architecture model distinguishes client systemsfrom server systems, which communicate over a computer network. Aclient-server application is a distributed system comprising both client andserver software. A client software process may initiate a communicationsession, while the server waits for requests from any client.

Client-server describes the relationship between two computer programsin which one program, the client program, makes a service request toanother, the server program. Standard networked functions such as emailexchange, web access and database access, are based on the client-server model. For example, a web browser is a client program at the usercomputer that may access information at any web server in the world.

Figure 11.1: Client-server Network


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c. Peer-to-peer (workgroup) Networking

A peer-to-peer (or P2P) computer network uses diverse connectivitybetween participants in a network and the cumulative bandwidth ofnetwork participants rather than conventional centralized resources where

a relatively low number of servers provide the core value to a service orapplication.

P2P networks are typically used for connecting nodes via largely ad hocconnections. Such networks are useful for many purposes. Sharingcontent files (see file sharing) containing audio, video, data or anything indigital format is very common, and real time data, such as telephonytraffic, is also passed using P2P technology.

4. Network topology

Computer networks may be classified according to the network topology uponwhich the network is based, such as bus network, star network, ring network,mesh network, star-bus network, tree or hierarchical topology network. Acomputer network topology is the physical communication scheme used byconnected devices.

Figure 11.2: Peer-to-peer Network

Figure 11.3: Network Topology


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a. Bus Topology

Bus networks use a common backbone to connect all devices. A singlecable, the backbone functions as a shared communication medium thatdevices attach or tap into with an interface connector. A device wanting to

communicate with another device on the network sends a broadcastmessage onto the wire that all other devices see, but only the intendedrecipient actually accepts and processes the message.

b. Ring Topology

In a ring network, every device has exactly two neighbors forcommunication purposes. All messages travel through a ring in the samedirection (either "clockwise" or "counterclockwise"). A failure in any cableor device breaks the loop and can take down the entire network.

c. Star Topology

Many home networks use the star topology. A star network features acentral connection point called a "hub" that may be a hub, switch or router.Devices typically connect to the hub with Unshielded Twisted Pair (UTP)Ethernet.

Compared to the bus topology, a star network generally requires morecable, but a failure in any star network cable will only take down onecomputer's network access and not the entire LAN. (If the hub fails,however, the entire network also fails.)

d. Tree Topology

Tree topologies integrate multiple star topologies together onto a bus. Inits simplest form, only hub devices connect directly to the tree bus, andeach hub functions as the "root" of a tree of devices. This bus/star hybridapproach supports future expandability of the network much better than abus (limited in the number of devices due to the broadcast traffic itgenerates) or a star (limited by the number of hub connection points)alone.

e. Mesh Topology

Mesh topologies involve the concept of routes. Unlike each of the previoustopologies, messages sent on a mesh network can take any of severalpossible paths from source to destination. (Recall that even in a ring,although two cable paths exist, messages can only travel in one direction.)Some WANs, most notably the Internet, employ mesh routing.

A mesh network in which every device connects to every other is called afull mesh. As shown in the illustration below, partial mesh networks alsoexist in which some devices connect only indirectly to others.


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1. A _______is the physical communication scheme used by connected devices.

2. ______ uses physical wiring to connect devices

11.3 Types of Network Hardware

Below is a list of the most common types of computer networks in order ofscale.

1. Personal area network

A personal area network (PAN) is a computer network used forcommunication among computer devices close to one person. Some examples ofdevices that are used in a PAN are printers, fax machines, telephones, PDAs andscanners. The reach of a PAN is typically about 20-30 feet (approximately 6-9meters), but this is expected to increase with technology improvements.

2. Local area network

A local area network (LAN) is a computer network covering a small physical

area, like a home, office, or small group of buildings, such as a school, or an airport.Current wired LANs are most likely to be based on Ethernet technology, althoughnew standards like ITU-T G.hn also provide a way to create a wired LAN usingexisting home wires (coaxial cables, phone lines and power lines).

3. Campus area network

A campus area network (CAN) is a computer network made up of an

interconnection of local area networks (LANs) within a limited geographical area. It

Figure 11.4 LAN


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can be considered one form of a metropolitan area network, specific to an academicsetting.

In the case of a university campus-based campus area network, the networkis likely to link a variety of campus buildings including; academic departments, the

university library and student residence halls. A campus area network is larger thana local area network but smaller than a wide area network (WAN) (in some cases).

The main aim of a campus area network is to facilitate students accessinginternet and university resources. This is a network that connects two or more LANsbut that is limited to a specific and contiguous geographical area such as a collegecampus, industrial complex, office building, or a military base.

4. Metropolitan area network

A metropolitan area network (MAN) is a network that connects two or more

local area networks or campus area networks together but does not extend beyondthe boundaries of the immediate town/city. Routers, switches and hubs areconnected to create a metropolitan area network.

5. Wide area network

A wide area network (WAN) is a computer network that covers a broad area(i.e. any network whose communications links cross metropolitan, regional, ornational boundaries [1]). Less formally, a WAN is a network that uses routers and

public communications links [1]. Contrast with personal area networks (PANs), localarea networks (LANs), campus area networks (CANs), or metropolitan areanetworks (MANs), which are usually limited to a room, building, campus or specificmetropolitan area (e.g., a city) respectively. The largest and most well-knownexample of a WAN is the Internet.

Figure 11.5 MAN

Figure 11.6 WAN


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6. Global area network

A global area networks (GAN) specification is in development by severalgroups, and there is no common definition. In general, however, a GAN is a modelfor supporting mobile communications across an arbitrary number of wireless LANs,

satellite coverage areas, etc. The key challenge in mobile communications is"handing off" the user communications from one local coverage area to the next.

7. Virtual private network

A virtual private network (VPN) is a computer network in which some of thelinks between nodes are carried by open connections or virtual circuits in somelarger network (e.g., the Internet) instead of by physical wires.

A VPN allows computer users to appear to be editing from an IP addresslocation other than the one which connects the actual computer to the Internet.


3. Current wired LANs are most likely to be based on ______ technology

4. A ______ is a computer network used for communication among computerdevices close to one person.

11.4 Conclusion

In this chapter you have studied the concept of compute network and itsadvantages. You have also learned the types and hardware of computer network.


1. Ethernet

2. PAN


1. Classify the computer network.

2. Explain the types of computer network.


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11.5 Glossary

1. IP (Internet Protocol) a set of protocols that allowcomputers to communicate with each other.

2. IP address (Internet Protocol address) A uniquenumber consisting of 4 parts separated by dots, e.g.222.113.245.80 Every machine that is on the Internethas a unique IP address. If a machine does not havean IP number, it is not really on the Internet. Mostmachines also have one or more Domain Names thatare easier for people to remember. As a user, thenumber assigned may either be static (alwaysremains the same) or may be offered on an asavailable basis each time the individual logs on. Ausers number is assigned by his ISP.

3. IRC (Internet Relay Chat) an online chat systemthat allows users to communicate in realtimeanywhere in the world. What makes ICR unique is it isability to accommodate more than two users at onetime.

4. ISDN (Integrated Services Digital Network) astandard used for the transmission of digital dataincluding voice and video signals over telephone wireswithout a modem at a significantly faster speed.

5. NetMeeting Provides people around the worldwith a whole new way of communicating. WithNetMeeting you can participate in meetings,collaborate in files using NetMeeting features, andshare information over the Internet or your corporateintranet.

6. Netscape Navigator A popular Web browserformerly called Mozilla and developed by NetscapeCommunications Corporation. It is widely felt that the

introduction of Netscape Navigator helped to bring theInternet to the masses.


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LESSON 12 NETWORK HARDWARE

TABLE OF CONTENTS:

12.0 OBJECTIVES

12.1 INTRODUCTION

12.2 NETWORK HARDWARE

12.3 CONCLUSION




12.7 GLOSSARY


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12.NETWORK HARDWARE


12.0 Objectives


Understand Network Hardware

12.1 Introduction

A network is a group of connected computers that allows people to shareinformation and equipment.

12.2 Network Hardware

All networks are made up of basic hardware building blocks to interconnectnetwork nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches,and Routers. In addition, some method of connecting these building blocks isrequired, usually in the form of galvanic cable (most commonly Category 5 cable).Less common are microwave links (as in IEEE 802.12) or optical cable (opticalfiber). An ethernet card may also be required.

1. Computers

A network can connect different types of computers, such as PC, Macintosh

computers, notebook computers. Computers usually come with networkingcapabilities built into the motherboard. Some computers are equipped with aNetwork Interface Card (NIC), which is expansion card inside a computer that offersnetwork capabilities. If a computer does not have network capabilities, you can adda NIC to the computer at any time.

2. Cables

Cables are the wires that physically connect computers and equipments on anetwork. There are two main types of computers:


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a. Twisted pair cable

Twisted pair cable is the most commonly used cable and is available inseveral different categories. Each category supports a different speed,which is measured in megabits per second (Mbps).

b. Fiber-optic cable

Fiber-optic cable carries information significantly faster and over longerdistances than twisted pair cable. Fiber-optic cable is also less susceptibleto interference and is more secure since others cannot eavesdrop on thecable. Since Fiber-optic cable can transmit information at a near infinitespeed, you will never need to upgrade the Fiber-optic cable.

Type of Cable SpeedTwisted Pair Category 5 (CAT-5) 100 Mbps

Category 5e (CAT-5e) 1,000 MbpsCategory 6 (CAT-6) 10,000 Mbps

Fiber-optic Near infinite

3. Router

A router is a device that determines the route, or path, along whichinformation is transferred on a network. A router is often used to connect a LAN toanother network or to allow every computer on a network to share one Internetconnection. A router connects to a switch or hub unless the router has built-in switchor hub that can connect all the computers on a network.

Table 12.11: Cable Speeds

Fi ure 12.2 Router

Figure 12.1 Cables


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4. Repeaters

A repeater is an electronic device that receives a signal and retransmits it at ahigher power level, or to the other side of an obstruction, so that the signal can coverlonger distances without degradation. In most twisted pair Ethernet configurations,

repeaters are required for cable which runs longer than 100 meters.

5. Hubs

A hub contains multiple ports. When a packet arrives at one port, it is copiedunmodified to all ports of the hub for transmission. The destination address in theframe is not changed to a broadcast address.

6. Bridges

A network bridge connects multiple network segments at the data link layer

(layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, ashubs do, but learn which MAC addresses are reachable through specific ports. Oncethe bridge associates a port and an address, it will send traffic for that address onlyto that port. Bridges do send broadcasts to all ports except the one on which thebroadcast was received. Bridges come in three basic types:

Local bridges: Directly connect local area networks (LANs)

Remote bridges: Can be used to create a wide area network (WAN) linkbetween LANs. Remote bridges, where the connecting link is slower thanthe end networks, largely have been replaced by routers.

Wireless bridges: Can be used to join LANs or connect remote stations toLANs.

7. Switches

A switch is a device that forwards and filters OSI layer 2 datagrams (chunk ofdata communication) between ports (connected cables) based on the MACaddresses in the packets. This is distinct from a hub in that it only forwards thepackets to the ports involved in the communications rather than all ports connected.Strictly speaking, a switch is not capable of routing traffic based on IP address (OSI

Layer 3) which is necessary for communicating between network segments or withina large or complex LAN. Some switches are capable of routing based on IPaddresses but are still called switches as a marketing term. A switch normally hasnumerous ports, with the intention being that most or all of the network is connecteddirectly to the switch, or another switch that is in turn connected to a switch.

Figure 12.3 Switch


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1. A _____ is a device that determines the route, or path, along which information istransferred on a network

2. A _______ connects multiple network segments at the data link layer

12.3 Conclusion

In this chapter you have studied the network hardware and its functions.


1. Router

2. Bridge


1. Describe the hardware components of computer network.





12.7 Glossary

1. Network Adapter The hardware that allows thecomputers that is part of a network to communicatewith each other.

2. Newsgroup an online discussion forum existingon any network, however, the term most often refers

to forums that use the Internet. There are literallythousands of topics for newsgroups


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3. NFS (network file system) a protocol used toaccess files over a network regardless of machine,operating system, or architecture.

4. Node an individual computer or hardware device

functioning as part of a network.

5. Noise any type of interference such as static thathinders communications. Telephone, cable, and radiotransmissions are all subject to noise.

6. NT File System (NTFS) File system developed for theWindows NT operating system. NTFS supports largedisks and files more efficiently than the FAT filesystem. NTFS adds many features that make itsuitable for even high-end corporate file systems.

Some of these are: 1. Built-in data security 2.Redundant data storage capabilities providing faulttolerance and data recoverability 3. Data compression4. More efficient data storage and retrieval for largedisks and files

7. Offline not connected, either to one of a computerssupportive hardware devices such as a printer orscanner, or to the Internet.

8. Online i) operational or connected, either to

one of a computers supportive hardware devicessuch as a printer or scanner, or to the Internet.

ii) to be actively connected to a network, such as theInternet.

9. Proxy server. existing between a client Webbrowser and a real server, a computer that cachescommon and often requested Web pages and holdsthem for easier access by users. Proxy servers allowfor faster access to Web pages for groups of users in

a particular area. For example, quick access topopular online services such as America Online isprovided by AOLs many proxy servers, which arepositioned regionally.

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