Fundamentals of Computer Networks: Sharing Resources and Communication, Assignments of Database Management Systems (DBMS)

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Unit 1: Fundamentals of

Computer Network

Need Of Computer Network  (^) Computer networks help users on the network to share the resources and in communication.  (^) File sharing: Networking of computers helps the network users to share data files.  (^) Information exchange To exchange data and information between different individual users, it is necessary to interconnect the individual users' computers  (^) Hardware sharing: Users can share devices such as printers, scanners, CD- ROM drives, hard drives etc. Without computer networks, device sharing is not possible.  (^) Application sharing: Applications can be shared over the network, and this allows to implement client/server applications  (^) User communication: Networks allow users to communicate using e-mail, newsgroups, and video conferencing etc.  (^) Network gaming: A lot of network games are available, which allow multi- users to play from different locations.

 Benefits/Advantages Of Computer

Network:1. Resource Sharing:

 (^) The goal is to make all programs, equipment's (like printers etc.), and especially data, available to anyone on the network without regard to the physical location of the resource and the user.  (^) Types of resources are:

1. Hardware: A network allows users to share many hardware devices such as printers , modems, fax machines, CD ROM, players, etc. 2. Software: sharing software resources reduces the cost of software  installation, saves space on hard disk. 2. Centralized Management of Resources:  (^) It is also known as client-server Network. In this type of system, multiple computers are joined to one powerful mainframe computer.  (^) The server or mainframe computer has huge storage and processing capabilities.  (^) The computers that are connected to the mainframe or server are called Clients or Nodes.  (^) These nodes are not connected to each other; they are only connected to server.

3. File sharing: A network makes it easy for everyone to access the same file and prevents people from accidentally creating different versions. 4.Increasing storage capacity: you can access files and multimedia, such as images and music, which you store remotely on other machines or network- attached storage devices.

a) LAN (Local Area

Network): •^ A LAN is a network that is used for communicating among computer

devices, usually within an office building or home.

• (^) LAN’s enable the sharing of resources such as files or hardware devices that

may be needed by multiple users.

• (^) Is limited in size, typically spanning a few hundred meters, and no more

than a mile.

• (^) Is fast, with speeds from 10 Mbps to 10 Gbps.
• (^) Requires little wiring, typically a single cable connecting to each device.
• (^) LAN’s can be either wired or wireless. Twisted pair, coaxial or fiber optic

cable can be used in wired LAN’s.

• (^) Every LAN uses a protocol – a set of rules that governs how packets

are configured and transmitted.

• (^) Has lower cost compared to MAN’s or WAN’s.
• (^) Nodes in a LAN are linked together with a certain topology.

These topologies include: Bus, Ring, Star.

• (^) Requires little wiring, typically a single cable connecting to each

device.

2) HAN (Home Area Network ):

 (^) A Home Area Network (HAN) is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices.  (^) An important function is the sharing of Internet access, often a broadband service through a Digital Subscriber Line (DSL) provider.

b) MAN (Metropolitan Area Network):

• (^) MAN Covers a larger geographical area than is a LAN.
• (^) A metropolitan area network (MAN) is a large computer network that usually spans a city or a large campus.
• (^) A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities.
• (^) A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations.
• (^) A MAN often acts as a high speed network to allow sharing of regional resources.
• (^) A MAN typically covers an area of between 5 and 50 km diameter.
• (^) Examples of MAN: Telephone company network that provides a high speed DSL to customers and cable TV network.

c) WAN (Wide Area Network):

• (^) WAN covers a large geographic area such as country, continent or even whole of the world.
• (^) A WAN is two or more LANs connected together. The LANs can be many miles apart.
• (^) To cover great distances, WANs may transmit data over leased high-speed phone lines or wireless links such as satellites.
• (^) Multiple LANs can be connected together using devices such as bridges, routers, or gateways, which enable them to share data.
• (^) The worlds most popular WAN is the Internet.