Report on Networking

REPORT ON NETWORKING

REPORT ON NETWORKING

SOMIL SAHAI PUNIT RATHEE ANKIT GUPTA AVDHESH K. SHIVASWAROOP REDDY AASHISH PRATAP RAGHUVANSHI

Report on Networking

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DEFINATION DEFINA TION OF NETWORKING: Networking is simply two or more computers connected together so that they can exchange information. A small network can be as simple as two computers linked together by a single cable.

INTRODUCTION OF NETWORKING:A computer network allows sharing of resources and informationamong information among devices connected to the network. The Advanced Research Projects Agency (ARPA) ARPA) funded the design of the Advanced Research P rojects Agency Network (ARPANAT) (ARPANAT) for the United States St ates Department of Defence. It was the first operational computer network in the world. Development of the network began in 1969, based on designs developed during the 1960s.

Types of networks :-

(1) Personal Area Network:A personal area are a network (PAN) is a compu ter network used for communication co mmunication among a mong computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless connections between d evices. The reach of a PAN typically extends extend s to 10 meters. A wired PAN is usually constructed with USB and Fire wire connections while technologies technologie s such as Bluetooth and infrared communication typically form a wireless Pan.

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(2) Loc l A A lo c l area ne

i

N t o

3

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ork (LAN) is a ne

ork that connects computers and devi ces in a limit ed

geographical area such as hom e school, comput er laboratory, office building, or closely positioned group of building s Ea ch computer or device on th e network is a node Current wir ed LANs are most likely to be based on Eth ernet t echnolog y, although n ew standards like ITU- T G.hn al so provid e a way to creat e a wired LAN using e isting hom e wir es (coaxial cables , phone lines and pow er lines).

Th e defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transf er rates, smaller geographic rang e, and no n eed for leased telecommunication lines. Current Eth ernet or other IEEE IEEE 802.3 LAN technologi es operat e at speeds up to 10 Gbit/ s. This is the data transf er rate. IEEE ha s pro jects investigating the

tandardization of 40 and 100 Gbit/ s . standardization

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(3) Hom A

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N t o

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:-

A Hom e ar ea n etwork (HAN) i s a residential LAN whi ch i s used for communi cation b etween digital d evices typically deployed in the hom e, usually a small numb er of personal computers and a ccessories, su ch as printers and mobil e computing d evi ces. An important

function is the sharing of Int ernet access, often a broadband servi ce through a CATV or Digital Subsc riber Line (D SL) provider. It can also be ref err ed as Offi ce area network (OAN).

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(4) C mpus N t o

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:

A campus n etwork is a computer network made up of an int erconnection of local area networks (LANs) within a limit ed g eographical area. The networking equipm ents (switches, rout ers) and transmission m edia (opti cal fiber, copper plant, Cat5 cabling etc.) ar e almost unive rsity, governm ent etc.). entir ely own ed (by the campus tenant / owner: an ent erprise, uni In the case of a uni versity campus-ba sed campus n etwork, the n etwork is lik ely to link a variety of  campus building s in cluding; a cademi c departm ents, the universit y librar y and stud ent residen ce halls.

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(5) Wide

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ea Network:Ar ea

A wid e area n etwork (WAN) is a computer n etwork that covers a larg e g eographic area such as a city, countr y, or span s even intercontin ental distances, using a communication s chann el that combines man y types of media such as telephone lin es, cables, and air waves . A WAN often uses transmission fa ciliti es pro vided by common carriers, su ch as telephon e compani es. WAN technologi es generally function at th e low er thr ee la ye rs of the OSI

ref erence mod el : the phys ical laye r, the data link la yer, and the network layer.

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(6) Glob l A

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N t o

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A global area network (GAN) i s a network used for supporting mobil e communications across an arbitrar y numb er of wir eless LAN s, satellite cove rag e areas, etc. Th e key chall enge in mobile communi cations is handing off th e user communication s from on e lo cal coverag e area to the n ext. In IEEE Pro ject 802, this involves a succession of t errestrial trial wirel ess lo cal area n etworks (WLAN).

(7) Ent

p is Pr iv t N t ork:-

An Enterprise Privat e Network is a network build by an enterprise to int erconnect the variou s company sites (produ ction sites, head offi ces, r emot e offices , shops etc.) in ord er to shar e computer r esour ces ove r the n etwork.

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(8) Virtu l Priv t N t ork:A virtual private network (VPN) is a computer network in whi ch som e of the links betw een nodes ar e carri ed by open conn ections or virtual cir cuit s in som e larger network (e.g., the Internet) instead of by physi cal wires. The data link la yer protocols of the virtual n etwork are said to b e tunnelled through the larger network when this is the case. One common appli cation is sec ure communi cations through the publi c Int ernet, but a VPN n eed not ha ve xam ple, explicit sec urity f eatur es, su ch as authentication or cont ent encryption. VPNs, for exam can be use d to separat e the traffic of diff erent user communities over an und erlying

network with strong security f eatur es. A VPN ma y ha ve best-effort performance, or may have a defined servi ce level agreement (SLA) betw een the VPN cu stom er and the VPN servi ce pro vider. Gen erally, a VPN has a topolog y mor e complex than point -to-point.

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(9) Int rn t ork:An Intern etwork is the connection of two or mor e privat e computer networks via a common L ayer 2) or routing technology (O SI Layer 3) and owned by separate entiti es swit ching (O SI La (publi c or privat e). Th e result is called an int ernetwork. The Internet is an aggregation of  man y int ernetworks; h ence it s nam e wa s shortened to Internet. Any interconn ection betw een public, privat e, comm ercial, industrial, or gove rnm ental networks ma y also b e defined as an int ernetwork or (mor e often) an extranet.

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(10) Int rn t:Th e Internet i s a global sys tem of interconn ected gove rnm ental, acad emic, corporate, public, and private computer networks. It is base d on the networking technologi es of the Internet. It is the su ccessor of the Advan ced Research Pro jects Ag en cy N etwork (ARPANET) developed by DARPA of the U.S. Departm ent of D ef ence . The Internet is also the communi cation s ba ckbon e und erlying the World Wide Web (WWW). Th e 'Internet' is mo s t commonl y sp elled with a capital 'I' as a proper noun, for hi storical r easons and to distingui sh

it from other g eneric intern etworks. Participant s in the Int ernet u se a di verse array of m ethod s of  several hundred do cum ented, and often standardized, protocols compatible with the Int ernet Protocol Suite and an addr essing sys tem (IP Addresses) administered by the Int ernet Assign ed Numb ers Authorit y and addr ess registries . Servi ce providers and larg e ent erprises exchang e information about th e reachability of their addr ess spa ces through the Bord er Gateway Protocol ( BGP), forming a redundant worldwid e mesh of tran smission path s.

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(11) Intran t and Ex tran t:Intranets and extranets ar e parts or ext en sions of a computer n etwork, usuall y a lo cal ar ea network. An intranet i s a set of networks, u sing the Internet Protocol and IP -ba se d tools such as w eb browsers and fil e transf er application s, i. e., are under the control of a single admini strative entit y. That admini strative entity clo ses the intranet to all but sp ecifi c, authoriz ed users.

Mo st commonly, an intranet i s the int ernal n etwork of an organization. A larg e intranet will typically ha ve at least one web server to provide users with organizational information. An extranet is a network that is limited in scope to a single organization or entity and also has limited conn ections to the networks of one or more oth er usuall y, but not necessarily, trusted org anization anizations or entiti es ( e.g., a company's custom ers ma y be give n a ccess to som e part of its intranet creating in this wa y an extranet, while at the sam e time the custom ers ma y not be considered 'trusted' from a securit y standpoint). T echnically, an extranet may also b e cat egorized a s a CAN, MAN, WAN, or other type of n etwork , although, although, by d efinition, an extranet cannot consist of a singl e LAN; it must have at least one conn ection with an external network.

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(12) Ov rlay N t ork :An o ve rlay network is a computer n etwork that is built on top of anoth er n etwork. Nodes in the overlay can be thought of a s being connected by virtual or logi cal link s, each of whi ch twor k. corresponds to a path, perhaps through many phys ical links, in the underl ying networ A sample overlay network: IP o ver SONET o ver Optical Nodes in the overlay can b e thought of as being connected b y virtual or logi cal links, each of  whi ch corr espond s to a path, p erhaps through man y phys ical link s, in the underlying network. For exampl e, many peer-to-peer n etworks ar e overla y networks because they run on top of th e Internet. Internet wa s built as an o ve rlay on the tel ephon e n etwork

[6]

.

Ove rlay n etworks ha ve been around sin ce the invention of n etworking when computer ing modem, before any data network sys tems were conn ected over telephon e lines using existed.

Ove rlay networks ha ve also been proposed as a wa y to improve Int ernet routing, such as through quality of  servi ce guarantees to achieve high er-quality streaming m edia. Pr evious proposals such as Int Serv, Diff Se h ave not seen wide acceptance largely Serv, and IP Multi cast ha because they requir e modifi cation of all rout ers in the network. On th e oth er hand, an overla y n etwork can be in crementally deployed on end -hosts running the overla y protocol software, without cooperation from I SPs. Th e ove rla y has no control ove r how packets are

rout ed in the underlying network betw een two ove rlay nodes , but it can control, for example, the sequence of overla y nod es a m ess age tra verses before reaching it s

destination.

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NETWORK TOPOLOGY:Network topolog y is defined as the interconnection of th e various elements (links, nodes, etc.)

of

a computer

network.

N etwork

Topologies

can

be

physi cal

or

logical.

Physi cal Topolog y m eans the physical design of a n etwork including th e devi ces , location and cable installation. tallation. Logi cal topolog y ref ers to the fact that how data a ctually transf ers in a network as opposed to its physi cal d esign.

(1) BUS TOPOLO GY:In local area networks wh ere bus topolog y is used, each ma chine is connected to a singl e cable. Ea ch computer or serve r is connected to the single bus cabl e through som e kind of  connector. A terminator is r equir ed at each end of th e bus cabl e to prevent the signal from

bouncing back and forth on th e bus cabl e. A signal from th e source tra vel s in both dir ections to all ma chines conn ected on th e bus cable until it find s the MAC address or IP addr ess on the network that is the int ended recipient. If the ma chine addr ess does not match the intended addr ess for the data, the ma chine ignores the data. Alt ernative ly, if th e data does mat ch the ma chine address, the data is acce pted. Sin ce the bus topolog y consists of only one wir e, it is rather inexpensive to implement when compar ed to oth er topologi es. How ever, the low cost of impl ementing the technolog y is off se se t by the high cost of  managing the network. Additionall y, since only one cable is utiliz ed, it can be th e single point of failur e. If th e network cable break s, the entir e network will be down.

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(2) STAR TOPOLOGY:In local area n etworks with a star topology, each network host is connected to a central hub. In contrast to the bus topolog y, th e star topology connects each nod e to the hub with a point -to-point conn ection. All traffi c that transverse s the network passes through th e central hub. Th e hub a cts as a signal boo s ter or repeat er. Th e star topolog y is consid ered

the easiest topolog y to design and impl ement. An advantag e of th e star topology is the simpli cit y of adding additional nod es. The primar y disad vantage of th e star topology is that

the hub r epresents a single point of failure.

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(3) RING TOPOLO GY:In local area networks where the ring topology is used, each computer i s conn ected to the network in a closed loop or ring. Ea ch ma chine or computer ha s a unique addr ess that is used for id entification purposes. The signal pa sses through each ma chine or computer connected to the ring in on e dir ection. Ring topologi es typically utilize a token pa ssing schem e, used to control access to the network. By utilizing thi s scheme, only one ma chine can transmit on th e network at a tim e. The ma chines or computers conn ected to the ring

act as signal boo sters or repeat ers whi ch strength en the signals that transve rse the network. The primary disad vantage of ring topology is the failur e of one ma chine will cause the entir e network to fail.

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(4) MESH TOPOLO GY:Th e valu e of fully mesh ed networks is proportional to th e expon ent of the numb er of  subscrib ers, a ssuming that communicating groups of any two endpoint s, up to and in cluding

all th e endpoints, is approximated by Reed's Law.

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(5) T REE TOPOLOGY :Th e typ e of n etwork topolog y in whi ch a central 'root' node (the top level of th e hierar chy) is conn ected to one or more oth er nodes that are one level lower in th e hierar chy (i.e., the second leve l) with a point -to-point link b etw een each of th e sec ond level nodes and the top

level central 'root' node, while each of th e second level nodes that are connected to the top level central 'root' nod e will al so ha ve one or more oth er nodes that are one l eve l low er in in the hierar chy (i.e., the third level) connec ted to it, also with a point -to-point link, th e top level central 'root' nod e b eing the only nod e that has no oth er node above it in the hierar chy (Th e hi erar chy of th e tree is symm etrical.) Ea ch node in the n etwork having a specific fix ed numb er, of nodes connected to it at the next low er level in th e hierar chy, th e

numb er, b eing ref err ed to as the 'branching factor' of the hierar chical tree.

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A VANTAGES OF NETWORK ING:-

Most

of

the

benefits

of

networking

can

be

divid ed

into

two

generic

cat egories: connectivity  and sharing . Networks allow computers, and hen ce their use rs, to

be connected tog ether. They al so allow for th e easy sharing of information and r es ources , and coop eration betw een the d evi ces in other wa ys. Here, in no parti cular order, are som e of the specific ad vantag es generally ass ociat ed with n etworking :  Conn ctivity and Communic ation : - N etworks conn ect computers and th e

users of those computers. Indi vidual s within a building or work group can be connected into l oca ocal  area networks (LANs) ; LANs in distant locations can be

interconn ected into larg er wide area networks (WANs) . On ce connected, it is possible for network user s to communi cat e with each other using technologi es such as electroni c mail. Thi s mak es th e transmission of busin ess (or non-business)

information easier, more effi cient and l ess expensive than it would b e without the network.  Data Sharing : - One of the most important uses of n etworking i s to allow the sharing of data. Befor e networking was common, an a ccounting employee who

wanted to pr epar e a report for her manager would have to produ ce it on hi s PC, put it on a flopp y disk, and then walk it o ver to the manag er, who would tran sf er th e data to her PC's hard disk. (This sort of shoe -ba sed network was som etimes sar casti cally called a sn eak er net.)  Hard are Sharing : - N etworks fa cilitat e the sharing of hardwar e d evi ces. For example, in stead of gi ving each of  10 emplo yees in a departm ent an expensive colour

printer (or resorting to the sneak er net again), one print er can be placed on the network for everyone to shar e.  Internet Access: The Intern et is itself an enormou s network, so wheneve r you

access the Int ernet, you ar e using a n etwork. The signifi cance of the Internet on modern soci ety is hard to exaggerat e, especially for those of us in t echnical fi elds.  Internet Access Shar ing: - Small computer networks allow multipl e users to shar e a single Int ernet connection. Sp ecial hardwar e devices allow the bandwidth of 

the connection to be easily allocat ed to various individuals as they need it, and p ermit an organization to pur cha se one high -speed connection instead of many slow er on es.

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DISADV ANTAG ES OF

NETWORK ING:-

Now that I ha ve portraye d the gr eat valu e and many use ful benefits of networking, I must bring you crashing back to earth with that old nemesis of th e realistic: TAN STAA FL. For those who are not H einlein fan s, this acronym stands for Th ere Isnt No Su ch Thing as a Free Lun ch. Even though networking really does represent a whol e that is gr eat er than the sum of its parts, it does have som e real and signifi cant costs and drawba cks associat ed with it. Here are a f ew of the items that balance against the ad vantag es of networking.  Net

ork

Hard

are, Soft are and Setup Costs :

- Computers don't  ju st

magi cally network themse lves , of  course. Setting up a network requir es an investm ent in hardwar e and software, as well as funds for planning, d esigning and implementing the n etwork. For a home with a small network of two or three PCs, this is relative ly inexpensive, po p o ssibly amounting to less than a hundr ed dollar s with toda y's low pri ces for network hardware, and operating sys tems already design ed for networks. For a larg e company, cost can easily run into t ens of thousands of  dollars or more.  Hard are and Soft

are Management and Administ ration Costs : - In all

but th e smallest of impl ementations, ongoing maintenan ce and manag ement of the network requires the car e and att ention of an IT prof ess essional. In a smaller organization that alr eady has a sys tem admini strator, a network may fall within thi s person's  job responsibiliti es, but it will tak e time awa y from other tasks. In mor e substantial organization s, a network adminis trator may need to be hir ed, and in

larg e compani es an entir e department may be necess ary.  Undesirable Sharing : - With the good com es the bad; while n etworking allows

the easy sharing of u seful information, it al so allows the sharing of und esirable data. One signifi cant sharing probl em in this r egard has to do with viru ses , which are easily spr ead ove r networks and the Internet. Mitigating these eff e cts costs more

time, money and admini strative effort.  Illegal or Undesirable Behaviour: - Similar to the point above, networking

facilitat es useful connectivity and communication, but also brings diffi culti es with it. Typical problems in clude abuse of  company res ources , distra ctions that reduce productivity, downloading of ill egal or illi cit materials, and even software pira cy. In larg er organizations, these iss ues mu st be managed through explicit poli cies and monitoring, which again, furth er increases management costs.