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Why using Network

• Networks help users on the network to share the resources and in communication. Can you imagine a world now without emails, online news papers, blogs, chat and the other services offered by the internet?

• The following are the important benefits of a computer network.• File sharing: Networking of computers helps the users to share data

files. • Hardware sharing: Users can share devices such as printers,

scanners, CD-ROM drives, hard drives etc.• 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.

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What is a Network?

• A network is a group of computers or devices connected together to share the resources like file, printer, services etc.

• A typical network contains users working at workstations (also known as client), running client operating systems like Windows 7 and store their files on a central server.

• The server computer has more resources like memory, disk space and more processing power compared with client computers. The server machine also run an Operating System, which has more processing capabilities compared with the client machine.

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Network Topologies

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Ring Network TopologyA ring topology sends messages clockwise or counterclockwise through the shared link.A failure in any cable or device breaks the loop and can take down the entire network.

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Bus Network TopologyA bus topology uses a single communication backbone for all devices.Bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result.

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Star Network TopologyA star topology typically uses a network hub or switch and is common in home networks.

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Tree Network TopologyThis diagram illustrates the tree network topology. A tree topology integrates the star and bus topologies in a hybrid approach to improve network scalability.

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Mesh Network TopologyA mesh topology provides redundant communication paths between some or all devices (partial or full mesh). Mesh topologies involve the concept of routes.

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LAN, MAN and WAN

• Local Area Network (LAN) is a network, which is limited to a single building, college campus etc.

• A Wide Area Network (WAN) spans over multiple geographic locations, which is composed of multiple LANs.

• A Metropolitan Area Network (MAN) refers to a network, which is located in a city or metropolitan area. If an organization has multiple offices in a city, the term that refers the network is called MAN.

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Types of Networks

• Peer-to-Peer (P2P) • A Peer-to-Peer network has no dedicated servers.• Number of workstations are connected together for

the purpose of sharing information or devices.• All the workstations are considered as equal. Any

one computer can act as client or server at any instance.

• This network is ideal for small networks where there is no need for dedicated servers, like home network or small business.

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Peer to Peer Network

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P2P Advantages• 1)  It is easy to install and so is the configuration of computers on this

network, 2)  All the resources and contents are shared by all the peers, unlike server-client architecture where Server shares all the contents and resources.3)  P2P is more reliable as central dependency is eliminated. Failure of one peer doesn’t affect the functioning of other peers. In case of Client –Server network, if server goes down whole network gets affected.4)  There is no need for full-time System Administrator. Every user is the administrator of his machine. User can control their shared resources. 5)  The over-all cost of building and maintaining this type of network is comparatively very less.

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P2P Disadvantages

1) In this network, the whole system is decentralized thus it is difficult to administer. That is one person cannot determine the whole accessibility setting of whole network.2)

Lack of security in this system. Viruses, spywares, trojans, etc malwares can easily transmitted over this P-2-P architecture.3)

Data recovery or backup is very difficult. Each computer should have its own back-up system

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Client-Server Networks

• The client/server model consists of high-end servers serving clients continuously on a network, by providing them with specific services upon request.

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Client-Server Advantage

• Centralized - Resources and data security are controlled through the server.

• Scalability - Any or all elements can be replaced individually as needs increase.

• Flexibility - New technology can be easily integrated into system.

• Accessibility - Server can be accessed remotely and across multiple platforms.

• security - Resources and data security are controlled through the server.

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Client-Server Advantage

• Network will run far better as data and resources are handled by a dedicated machine

• Backup - as all data is stored centrally it is easy to backup

• Support and management - as the server controls the majority of settings on the network etc, the job of support is far easier than P2P.

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Client-Server Disadvantages

• More expensive than a peer-to-peer network you have to pay for the server cost.

• When the server goes down or crashes all the computers connected to it become unavailable to use.

• When everyone tries to do the same thing it takes a little while for the server to do certain tasks.

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Client/Server

• NOS - Network Operating System that includes special functions for connecting computers and devices into a Local-Area-Network(LAN). Some operating systems, such as UNIX and the Mac OS, have networking functions built in. The term network operating system, however, is generally reserved for software that enhances a basic operating system by adding networking features. Novell Netware, Artisoft's LANtastic, Microsoft Windows Server, and Windows NT are examples of an NOS.

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Network Terms

• Client• Server• NOS (Network Operating System )• NIC (Network Interface Card)• Host• Node• Segment• Backbone• Topology• Protocol

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Network Terms

• Packet• Addressing• Transmission media

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How Networks Are Used

• Network services– Functions provided by a network– E-mail– Printer sharing– File sharing– Internet access and Web site delivery– Remote access capabilities– Voice (telephone) and video services– Network management

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File and Print Services

• File services– Capability of server to share data files,

applications and disk storage space• File server

– Provides file services• File services provide foundation of networking• Print services

– Share printers across network– Saves time and money

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Access Services

• Allow remote user network connection• Allow network users to connect to machines

outside the network• Remote user

– Computer user on different network or in different geographical location from LAN’s server

• Network operating systems include built-in access services

Communications Services

• Mail server– Computer responsible for e-mail storage and transfer– Intercept spam– Handle objectionable content– Route messages according to rules– Provide Web-based client for checking e-mail– Notify administrators or users if certain events occur– Schedule e-mail transmission, retrieval, storage,

maintenance– Communicate with mail servers on other networks

• Mail server runs specialized mail server software25

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Internet Services

• Web server– Computer installed with appropriate software to

supply Web pages to many different clients upon demand

• Other Internet services– File transfer capabilities– Internet addressing schemes– Security filters– Means for directly logging on to other Internet

computers

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Becoming a Networking Professional

• Job market– Many job postings for computer professionals– Expertise levels required vary

• To prepare for entering job market:– Master general networking technologies– Select and study areas of interest– Hone communication and teamwork skills– Stay abreast of emerging technologies– Consider professional certification– Get to know others in your field

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Mastering the Technical Challenges

• Skills to acquire– Installing, configuring, troubleshooting network

server and client hardware and software– Understanding characteristics of transmission media– Understanding network design– Understanding network protocols– Understanding how users interact with network– Constructing a network with clients, servers, media,

and connectivity devices

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Mastering the Technical Challenges

• Pick one or two areas of concentration• Specialties currently in high demand

– Network security– Convergence– In-depth knowledge about one or more NOSs

• UNIX, Linux, MAC OS X Server, Microsoft Windows Server 2008 R2

– Network management– Wireless network design– Configuration of routers and switches– Centralized data storage and management

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Developing Your “Soft Skills”

• Soft skills– Not easily measurable– Important to networking projects

• Examples of soft skills– Customer relations– Oral and written communications– Dependability– Teamwork– Leadership abilities

Pursuing Certification

• Certification process– Mastering specific material

• Hardware system, operating system, programming language, software application

– Proving mastery• Pass exams

• Professional organizations– CompTIA

• Network+

• Vendors– Microsoft , Cisco

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Pursuing Certification (cont’d.)

• Benefits– Better salary– Greater opportunities– Professional respect– Access to better support