Computer Networking
SYNOPSIS
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Computer Networking
“COMPUTERNETWORK TECHNOLOGIES”
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KARNATAKA STATE OPEN UNIVERSITY Manasagangotri, Manasagangotri, Mysore
For The Partial Fulfillment of Technology In Information Technology
Submitted By:-............................. Enrollment No:-............................ 20
Computer Networking
Table of Content
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Title of of th the Di Dissertation Appr Approv oval al by the the In Inter ternal and and Ext Extern ernal Supervisors(Annexure-1) 3. Bio Bio data data of the the Inter ternal and and Ext Extern ernal Supervisors 4. Introduction an and ob objectives of of th the Dissertation. 5. Components of a Network 6. Types of Networks 7. Topology of Networks 8. Scope of the solution 9. Analysis 10. Future Future scope scope and and furth further er enh enhan ancem cemen ent t Of the Dissertation. 11.Bibliography
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ANNEXURE -1
Approval by Internal Supervisor
This is to certify that the project entitled, “Com “Compu pute tern rnet etwo work rk Tech Techno nolo logi gies es”i ”iss the the bona bonafi fide de work work carr carrie ied d out out by ....... .......... ....... ....... ... studen studentt of M.Tech M.Tech during during the year year 2009-20 2009-2011,i 11,impa mparti rtial al fulfillment of the requirements for the award of the Degree of Master of Tech Techno nolo logy gy in Info Inform rmat atio ion n Tech Techno nolo logy gy from from Karn Karnat atak aka a Stat Statee Open Open University that the Project has under the th e guidance of mine Supervision.
Place:...................... Date:....................
)
Full Name& Signature of the Internal Supervisor
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ANNEXURE-1
Approval by External Supervisor
This is to cerity that project entitled “Computernetwork Technologies” is the bonafide work carried out by ..............................a student of M.Tech,during the year 20092011, inpartial fulfillment of the requirement for the award of the Degree of Master of Techonolgy in Information Technology from Karnataka State Open University, that the project has under my guidance and that the project has not formed the basis for the award previously of any degree, diploma, associateship, fellowship or any other similar title.
Full Name & Signature Of the External Supervisor Place: Date:20
Computer Networking
Table of Content
1. 2.
Title of of th the Di Dissertation Appr Approv oval al by the the In Inter ternal and and Ext Extern ernal Supervisors(Annexure-1) 3. Bio Bio data data of the the Inter ternal and and Ext Extern ernal Supervisors 4. Introduction an and ob objectives of of th the Dissertation. 5. Components of a Network 6. Types of Networks Topology of Networks 8. Scope of the solution 9. Analysis Future scope and furtherenhancement Of the Dissertation. 11.Bibliography 7.
10.
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Introduction A computer network, often simply referred to as a network, is a collection of computers of computers and devices connected by communications channels that facilitates communications among users and allows users to share resources with other users. Networks may be classified according to a wide variety of characteristics. A computer network allows sharing of resources and information among devices connected to the network. Computer networks can be used for several purposes: •
Facilitating Communications Communications
Using a network, people can communicate efficiently and easily via e-mail, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing. •
Sharing Hardware
In a networked environment, each computer on a network can access and use hardware on the network. Suppose several personal computers on a network each require the use of a laser printer. If the personal computers and a laser printer are connected to a network, each user can then access the laser printer on the network, as they need it. •
Sharing files, data and information
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In a network environment, any authorized user can access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks. •
Sharing Software Users connected to a network can access application programs on the network.
Fig 1 gives an example of a network in a school comprising of a local area network or LAN connecting computers with each other, the internet, and various servers.
Access to: Internet content & learning resources, Scoilnet etc Email communication
File and Print Server CD or Multimedia Servers Printers , Scanners etc
Users computers Cache, Proxy, Filtering, Firewall Server
School ‘Local Area Network’ (LAN) Modem or Router
Other users, computers
Fig 1: Representation of Network in a school.
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Objectives of Dissertation •
To study how implement a functional networking. Many challenges must be faced especially in the Areas of connectivity,reliability,network management And flexibility.
To study how connecting systems to support communication among disparate technologies using different-different internet services •
To provide centralized support and troubleshooting in an internetwork •
To provide security within an internetwork for an internetwork to function smoothly and secure form the perpective of protecting the private network from viruses And outside attacks. •
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To differentiate leased line & dail up Network with Cable Network.
Components of a Network A computer network comprises the following components: 20
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A minimum of at least 2 computers • Cables that connect the computers to each other, although wire wireles lesss commu communi nica catio tion n is beco becomi ming ng more more commo common n (see (see Advice Sheet 20 for more information) • A network interface device on each computer (this is called a network interface card or NIC) A ‘Sw ‘Switch’ used to switch the data from one point to • anot anothe her. r. Hubs Hubs are are outda outdated ted and and are littl littlee used for new new installations. • Network operating system software •
Structured Cabling The two most popular types of structured network cabling are twisted-pair (also known as 10BaseT) and thin coax (also known as 10Base2). 10BaseT cabling looks like ordinary telephone wire, except that it has 8 wires inside instead of 4. Thin coax looks like the copper coaxial cabling that's often used to connect a Video Recorder to a TV.
10BaseT Cabling When 10BaseT cabling is used, a strand of cabling is inserted between each computer and a hub. If you have 5 computers, you'll need 5 cables. Each cable cannot exceed 325 feet in length. Because the cables from all of the PCs converge at a common point, a 10BaseT network forms a star configuration. Fig 4a shows a Cat5e cable, with a standard connector, known as an RJ-45 connector. Fig 4b shows a standard Cat5e Wall Outlet socket which the cables are connected to. 20
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Fig 4c shows a standard Cat5e Patch Panel Wall Outlet socket which is used to terminate the cables from various points in the school bank to a central point. Fig 4d shows a wall mounted cabinet used to house and protect patch panel cables and connectors.
Fig 4a: Cat5e Cable and a close up of RJ-45 connector
Fig 4b: Cat5e Wall Outlets
Fig 4c: Cat5e Patch Panel
Fig4d: Wall Mounted Cabinet
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10BaseT cabling is available in different grades or categories. Some grades, or "cats", are required for Fast Ethernet networks, while others are perfectly acceptable for standard 10Mbps networks--and less expensive, too. All new networks use a minimum of standard unshielded twisted-pair (UTP) Category 5e 10BaseT cabling because it offers a performance advantage over lower grades.
Network Interface Card (NIC) A NIC (pronounced 'nick') is also known as a network card. It connects the computer to the cabling, which in turn links all of the computers on the network together. Each computer on a network must have a network card. Most modern network cards are 10/100 NICs and can operate at either 10Mbps or 100Mbps. Only NICs supporting a minimum of 100Mbps should be used in new installations schools. Computers with a wireless connection to a network also use a network card (see Advice Sheet 20 for more information on wireless networking).
Fig 5: Network Interface Cards (NICs) Hub and Switch
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A hub is a device used to connect a PC to the network. The function of a hub is to direct information around the network, fac facil ilit itat atin ing g comm commun unic icat atio ion n betw betwee een n all all conn connec ecte ted d devi device ces. s. However However in new installations installations switches should should be used instead of hubs as they are more effective and provide better performance. A switch, which is often termed a 'smart hub'. Switch tches and hubs are techn chnolog logies ies or ‘boxes’ to which ich computers, printers, and other networking devices are connected. Switches are the more recent technology and the accepted way of building today's networks. With switching, each connection gets "dedicated bandwidth" and can operate at full spe speed ed.. In cont contra rast st,, a hub hub shar shares es band bandwi widt dth h acro across ss mult multip iple le connections such that activity from one PC or server can slow down the effective speed of other connections on the hub.
Now more affordable than ever, Dual-speed 10/100 autosensing switches are recommended for all school networks. Schools may want want to con conside siderr upgra pgradi ding ng any any hub hub bas based netw networ orks ks with with switch switches es to improve improve networ networkk performan performance ce – i.e. i.e. speed of data data on the network.
Fig 6a: An 8 port Hub
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Fig 6b: 2 Examples of 24 port Switches Switches
Types of Networks There ere are many categ tegories under which ich netwo tworks can be classified into. The following types of network are categorized on the basis of the number of systems or devices that are under the networked area: LAN - Local Area Network
A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not subnet . always implemented as a single IP subnet In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring . 20
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WAN - Wide Area Network
As the term implies, a WAN spans WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth. A WAN is a geographically-dispersed collection of LANs. A network device called a router connects router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address. A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM like ATM , Frame , Frame Relay and X.25 X.25 for connectivity over the longer distances.
Another type of network classification is the following, When a group of two or more computers are linked together, they can broadly be classified into two types of networks: 1.
are more more comm common only ly imple impleme ment nted ed Peer-to-p Peer-to-peer eer networks networks are where less then ten computers are involved and where strict sec secur urit ityy is not not nece necess ssar ary. y. All All comp comput uter erss have have the the same same status, hence the term 'peer', and they communicate with each other on an equal footing. Files, such as word processing or spreadsheet documents, can be shared across the network and all the computers on the network can share 20
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devices, such as printers or scanners, which are connected to any one computer.
Peer to Peer Network
Fig 2: Peer to Peer Networking
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Clien Client/se t/serve rverr ne netwo tworks rks are more suitable for larger netw netwo orks. rks. A cent centra rall com computer uter,, or 'ser 'serve ver' r',, acts cts as the storage location for files and applications shared on the netwo twork. Usually lly the serv erver is a higher than aver verage performance computer. er. The The server also con controls the network access of the other computers which are referred to as the the 'clie 'client nt'' comp comput uters ers.. Typic Typical ally, ly, everyb everybod odyy will will have have access to use the client computers for their work but only the network administrator will have access rights to the server.
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File Server
Other equipment
Fig 3: Client - Server Networking
In addition to these types, the following characteristics are also used to categorize different types of networks: Topology The shape of a local-area network (LAN) or other communications system is known as its topology. There are three principal topologies used in LANs:1.
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Bus topology: All devices are connected to a central cable, called the bus or backbone. Bus networks are relatively inexpensive and easy to install for small networks. Ethernet systems use a bus topology.
Advantages of bus topology:
Easy to implement and extend
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Well suited for temporary networks that must be set up in a hurry Typically the least cheapest topology to implement Failure of one station does not affect others Disadvantages of bus topology:
Difficult to administer/troubleshoot Limited cable length and number of stations A cable break can disable the entire network; no redundancy Maintenance costs may be higher in the long run Performance degrades as additional computers are added Ring topology: All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. Ring topologies are relatively expensive and difficult to install, but they offer high bandwidth and can span large distances.
Advantages of ring topology:
Growth of system has minimal impact on performance All stations have equal access Disadvantages of ring topology: 20
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Most expensive topology Failure of one computer may impact others Complex Star topology: All devices are connected to a central hub. Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub.
Advantages of star topology:
Easy to add new stations Easy to monitor and troubleshoot Can accommodate different wiring Disadvantages of ring topology:
Failure of hub cripples attached stations More cable required
These topologies can also be mixed. For example, a bus-star network consists of a high-bandwidth bus, called the backbone, which connects a collection of slower-bandwidth star segments. 20
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Protocol An agreed-upon format for transmitting data between two devices. The protocol determines the following: i. The The type type of err error or checki checking ng to be be used used dat data a comp compres ressi sion on method, ii. If any any how how the the send sendin ing g dev device ice will will ind indica icate te tha thatt it has has finished sending a message iii. iii. How How the the rece receiv ivin ing g devi device ce wil willl indi indica cate te tha thatt it it has has received a message. There are a variety of standard protocols from which programmers can choose. Each has particular advantages and disadvantages; for example, some are simpler than others, some are more reliable, and some are faster. From a user's point of view, the only interesting aspect about protocols is that your computer or device must support the right ones if you want to communicate with other computers. The protocol can be implemented either in hardware or in software. Common types of protocols: •
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Internet Protocol Transmission Control Protocol Hypertext Transfer Protocol Post Office Protocol File Transfer Protocol 20
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Importance of Protocol
The protocols in human communication are separate rules about appear appearanc ance, e, speaki speaking, ng, listen listening ing and unders understan tandin ding. g. All these these rules, also called protocols of conversation, represent different layers of communication. They work together to help people successfully communicate. The need for protocols also applies to network devices. Computers have no way of learning protocols, so network engineers have written rules for communicat communication ion that must be strictly followed for successful host-to-host com communica ication. These ese rules apply to diff ifferen rent layers yers of sophistication such as which physical connections to use, how hosts listen, how to interrupt, how to say good-bye, and in short how to communicate, what language to use and many others. These rules, or protocols, that work together to ensure successful communication are grouped into what is known as a protocol suite. suite.
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Dissertation Category
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Computer network Technologies
Tools-Used • • • •
ISP’S Networking Devices Various Networking Technologies Networking protocols
Platform used • •
Proprietary LAN server environment LAN OFC network
Architecture
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The term architecture can refer to either hardware or software, or to a combination of hardware and software. The architecture of a system always defines its broad outlines, and may define precise mechanisms as well. An open architecture allows the system to be connected easily to devices and programs made by other manufacturers. Open architectures use off-the-shelf components and conform to approved standards. A system with a closed architecture, on the other hand, is one whose design is proprietary, making it difficult to connect the system to other systems. The The diff differ eren ence ce betw betwee een n a topo topolo logy gy and and an arch archit itec ectu ture re.. A topology is conc concer erne ned d with with the the phys physic ical al arra arrang ngem emen entt of the the network components. In contrast, an architecture addresses addresses the components themselves and how a system is structured (cable acce access ss me meth thod ods, s, lower ower leve levell proto rotoco cols ls,, topo topolo log gy, etc. etc.). ). An example of an architecture is 10baseT Ethernet which typically uses the start topology.
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Wireless Networks The term 'wireless network' refers to two or more computers communicating using standard network rules or protocols, but without the use of cabling to connect the computers together. Ins Inste tead ad,, the com compute puters rs use use wire wirele less ss radi radio o sign signa als to send end information from one to the other. A wireless local area network (WLAN) consists of two key components: an access point (also called a base station) and a wireless card. Information can be transmitted between these two components as long as they are fairly close together (up to 100 metres indoors or 350 metres outdoors).
Fig 7a: Wireless Access point or Wireless Basestation
Suppliers would need to visit the schools and conduct a site survey. This will determine the number of base stations you need and the best place(s) to locate them. A site survey will also enable each supplier to provide you with a detailed quote. It is important to contact a number of different suppliers as prices, equi equipm pmen entt and and opin opinio ions ns may may vary vary.. When When the the term term 'wir 'wirel eles esss network' is used today, it usually refers to a wireless local area network or WLAN. A WLAN can be installed as the sole network in a school or building. However, it can also be used to extend an existing wired network to areas where wiring would be too difficult or too expensive to implement, or to areas located away from the main network or main building. Wireless networks can 20
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be conf config igur ured ed to prov provid idee the the same same netw networ orkk func functi tion onal alit ityy as wired networks, ranging from simple peer-to-peer con configurations to large rge-sc -scale netw etworks acco ccommodating ing hundreds of users.
Fig 7b: Desktop PC Wireless LAN card Laptop PC Wireless LAN card
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Bibliography •
Computer Networks by Tanenbaum
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All about Computer Network By Manohar Lodia
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Data communication By Ferozon
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http://www.cisco.com
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http://www.networkessential.com
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http://www.google.com
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