Network Fundamentals

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- Networks Classificationnof g i n (Based on Topologies) r f o r

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Bus Topology l • In Bus topology the computers are connected a i t n serially. e d i f • Characteristics : on

C it reaches – Data travels to all the system -before g destination node. n i n – Easy to install. r a e – Cheap less cablingLrequired. f o – Time taken forr data transfer between systems are not e t same. n e – If one cable C fails whole network fails. – Difficult to find a fault and troubleshoot it.

Bus Topology l a ti

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Star Topology • In star topology all the computers are connected lto a central place called HUB/Switch. tia

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•Characteristics :  Easy to install.

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g n Costly lot of cables required. i n r a e Time taken for dataLtransfer between systems are same. f o If one system or r cable fails only the particular system e t will not be accessible in a network. n e C  Easy to find a fault and troubleshoot it.

If hub/switch fail the whole network fails.

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Ring Topology l a i • In ring topology all the computers are connected t in n e round or ring fashion. d i f n o •Characteristics : C Transmission is done only if the system has free token.Also g n ring. i called as Token Passing or token n r a  Easy to install. e L f Cheap o r e t data transfer between systems are not same. Time taken for n e C If one system or cable fails whole network fails. Difficult to find a fault and troubleshoot it.

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FDDI Ring

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FDDI Ring

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Mesh Topology l a • In Mesh topology all the computers are i connected t to each others using separate cables. en id f n •Characteristics : o C All system can communicate with each other g n i rn Costly, (nxn-1)/2 acables required. N is the number of systemsLe in a network f o r If particular ecable fails the systems connected by t nalone will not able to communicate b/w those cable e C but they can communicate with all themselves other systems.

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- Networks Classificationnof g i n (Based on Geographical location) r f o r

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l Local Area Network (LAN) a ti n e d

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• Physical Distance Betweeno the computers C will be around 100 meters. g

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r small area ,such as a •It covers a relatively a e L building ,home or fan office. o r

e t •Used to share printers ,files and other n Ce the LAN. resources over •Example : School Lab

Local Area Network l ia t n (LAN) e d i f n

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Metropolitan Area Network (LAN) al i t n

e d i f • Physical Distance Between the computers will n o range from 100 meters to 10 Kilometers. -C g ,such as a offices •It covers a relatively largein area rn in the same city or to from one place to other aplace e connect near by building L f o r •Used to share printers ,files and other resources e t n over the Network. e C

•Example : University Labs, Sutherland Velachery to Tidel Park.

Metropolitan Area Network (LAN) al g n ni

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l Wide Area Network (WAN) a ti

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• Physical Distance Between thefi range from 10 Kilometers and Above on

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C •It covers a relatively largegarea ,such as a offices in from country to anotherrn country a e •Used to share printers, files and other resources L f o over the Network. r e t n •Example :e Banks in India, Internet, Sutherland C INDIA offices USA, CANADA,

l Wide Area Network (WAN) a ti i f n

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- Networks Classificationnof g iGrouping) n (Based on r f o r

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l a i Peer to Peer Network t n e id f n o • Each computer is attached to - Cthe network in a g to the other units on ring or bus fashion and is equal n i n r the network. a e L •This network is useful f if we have a small network o r and there is no eneed for managing or security. t n e •It can alsoCbe defined as Collection of computers interconnected together to share information and resources without any administration .

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Client / Server Network l a ti

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•In this dependent workstations,referred to e as clients, d i f operate in conjunction with a dedicated n master computer o called a server.

C •Client request the server and sever serves the client if the g n it requested. i client has permission to access what n r ain case we need management •This type of network is need e L and security ,Example f :Office computers in different o departments. r e t n •There are two types of administration : e C •Centralized Administration : One system controls all the other systems. •Distributed

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OSI ModelCo g n ni

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The International Standards Organization (ISO) l data Defines seven layers and the function ofiathe t n flow within each layer call the OSI model e (Open d i f systems interconnection. n

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OSI Model l a ti

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Protocols g n i n

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Protocols 1. A network’s protocol is the “language” thatiaisl used t for data transmission. n e d 2. Set of rules and regulation thatfi governs the communication between systems. on - C protocols, 3. The following are the various network g n • TCP/IP i n r • NetBEUI a e L • IPX/SPX f o • Apple Talk r

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TCP / IP • The most popular protocol l a i t • Used in internet. n e • Provides a logical address calledfidan IP Address

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IP Address l a ti

• Internet Protocol Address. n e • A numeric address that is given toidservers and f n users connected to the Internet. o C • Two versions: IPV4 (32bits) g and IPV6 (128bits)

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IP Address classes Network Class

Address Range of First Field

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1-126

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128-191

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192-223

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Number of Networks Supported

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16,777,214

65,534

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Network devices g n ni

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The Devices Used in Networking are : • NIC – Network Interface Card

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• Hub

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• Switch • Router • Modem

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l Network Interface Card a ti n e d

i to a network. f • Required for connecting systems n o The NIC cards depend on the topology used in C the network. g n i n

r Token ring or FDDI ring • It may use Ethernet, a technologies Le f o r

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Network Interface Cards l a ti

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Ethernet NIC With RJ-45 and BNC

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FDDI Card

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Token Ring NIC With RJ-45 and AUI

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n e C Layer 1 device which operates on the physical layer of the OSI model

Switch l a ti

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n e C Layer 2 device which operates on the data link layer of the OSI model

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Device used to re generate weak signal for retransmission across large distance.

Modem l a ti

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e Used to connect thetcomputer to an ISP (Internet service provider) n e Via analog transmission (telephone) line C

Router l a ti

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Layer 3 deviceen which works on the network layer of the C OSI model.

Cables There are different types of cable used depending l a i t upon the type of network. n • Coaxial cable • Twisted Pair cable

g n i • OFC –Optical fiber cable n r a e L f o r e t n Ce

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Coaxial Cable Widely used in CATV networks. Types, • Thick-net

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• Thin-net

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- of the copper core. As Classifications are based on the gauge gaxis of cables one inner n the name suggest co-axial has two i n r conductor and again a conductor , insulator ,outer mesh a e L overall insulator. f o r

e as 10 Base 5 thicknet,10 Base 2 t These cable are called n e thinnet. C

Cables Plenum/PVC cable

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3. Most commonly used coaxial cablesenuse a PVC outer sheath to protect the cable. fid n o 4. PVC is not fire resistant and cannot, by code, be C used in overhead or plenumgareas in offices. n i 5. Plenum cable uses a special fire-resistant outer n r burn as quickly as PVC. sheath Teflon that willea not L more but is required in most 6. Plenum cables costs f o areas. r

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Coaxial Cable l a ti

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Twisted Pair Cables

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Twisted-pair

cable contains pairs of wires that are o C twisted around each other.Twists are for g n preventing data attenuation. i

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e Twisted Pair cables There are two typesLof

f o • Shielded Twisted r Pair (Extra shielding to reduce e t EMI) n e C • Unshielded Twisted Pair

Twisted-Pair Cable Standards l a i t n e

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Twisted Pair Cables

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UTP

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Optic Fiber Cable • Fiber-optic cabling offers the prospect of very l high performance links for LAN implementation. a i • •

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t n e It can handle much higher data-transfer rates d i f than copper conductors. n o Handle longer distances between - C stations before g signal deterioration (attenuation) becomes a n i n problem. r a e L It offers a high degree of security for data f communications.r oBecause it does not radiate e t electro magnetic field that can be detected n e outside theCconductor.

• It shows a decided signal loss when it is tapped into.

Optic Fiber Cable

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Connectors l a ti

BNC Connector

T Connector

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RJ-45 Connector

RJ-45 Connector with cable

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RJ-11 Connector

Connectors IDC/UDC Connectors

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The IBM-type Data Connector and the Universal Data Connector (UDC)onare two types of - C computer systems. cable connectors used by IBM g These connectors were designed n to be universal i ncommunications networks. r data connectors for IBM a e Neither of these types L of connectors is commonly f o found in PC systems r

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o Way to Network PCs C g n ni

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Way to Network PCs l a ti

• Ethernet • Token Passing

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• Dial-Up Networks • Direct Connection • ISDN Connection • DSL Connection

• Cable Connection fL

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• Satellite Connection te

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• Wireless Connections • Connecting LAN’s

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Dial-up Slow speed internet connection preferable for home l users. Cheap to install. a i

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Direct Connection Used to connect two computers in a peer-to-peer style without l a i t any need for specialized network devices. n - COM COM LPT - LPT

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ISDN Connection Ideal for home and small business. Two types of services offered, BRI – Basic Rate Interface PRI – Primary Rate Interface

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DSL Connection Telephone companies have begun to offer la new ia and high-bandwidth connection service to home t n e business customers in the formid of Digital Subscriber Lines (DSL). nf

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This technology provides high-speed g communication links by in using the existing n r telephone lines to generate bandwidths ranging a e L up to 9Mbps or more.f o r

e limitations and line-quality However, distance t nreduce the actual throughput that e conditions can C can be achieved with these connections.

DSL Connection l a ti

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Cable Connection Type of internet connection offered via coaxial cable. Services offered, l a CATV signals i t Internet en

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Satellite Connection Expensive type of internet connection but not restricted to any geographic location. al

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Wireless Connection Easy to install, provides mobility within an organization. Ideal for l SOHO environments. a i

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