Top Banner
Data Communication & Networking Data Communication & Networking
46
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Data Communication & Networking

Data Communication & NetworkingData Communication & Networking

Page 2: Data Communication & Networking

IntroductionIntroduction

Data Communication & Networking are changing the way we do business and the way we live.

For better business decision we require immediate access to accurate information.

Technological advances are making it possible for communication links to carry more & faster signals.

When we communicate we share information, this sharing can be local or remote.

The term telecommunication which includes telephony, telegraphy & television means communication at a distance (Tele is Greek for “far”)

Page 3: Data Communication & Networking

Data CommunicationsData Communications

DataData Information presented in whatever form is agreed upon by the Information presented in whatever form is agreed upon by the

parties creating and using the dataparties creating and using the data Data communicationData communication

Exchange of data between two devicesExchange of data between two devices Via some form of transmission medium such as wire cableVia some form of transmission medium such as wire cable

Fundamental characteristics of data communicationFundamental characteristics of data communication Delivery : System must deliver the data to the correct Delivery : System must deliver the data to the correct

destination.destination. Accuracy: System must deliver the data accurately. Accuracy: System must deliver the data accurately. Timeliness:Timeliness: Jitter: Refer to the Variation in the packet arrival time For Ex Jitter: Refer to the Variation in the packet arrival time For Ex

assume that video packet are sent every 30 ms. If some of the assume that video packet are sent every 30 ms. If some of the pocket arrive with 30 ms delay and others with 40 ms delay, an pocket arrive with 30 ms delay and others with 40 ms delay, an uneven quality in the video is the resultuneven quality in the video is the result.. ..

Page 4: Data Communication & Networking

Five Components of Data Five Components of Data CommunicationCommunication

Page 5: Data Communication & Networking

Five Components of Data Five Components of Data CommunicationCommunication

Message: Information(data) to be communicatedMessage: Information(data) to be communicated

Sender : Device that sends the data message. It can be computer, telephone handset, Sender : Device that sends the data message. It can be computer, telephone handset,

video camera & so onvideo camera & so on

Receiver: That receive the message . It can be computer, telephone handset, video Receiver: That receive the message . It can be computer, telephone handset, video

camera & so on camera & so on

Transmission medium: Physical path by which a message travels. Ex. Twisted pair, Transmission medium: Physical path by which a message travels. Ex. Twisted pair,

coaxial cable, fiber-optical cable, radio waves. coaxial cable, fiber-optical cable, radio waves.

Protocol: A set of rules that govern data communication without a protocol device may be Protocol: A set of rules that govern data communication without a protocol device may be

connected but not communicating, just as speaking French cannot be understand by a connected but not communicating, just as speaking French cannot be understand by a

person who speak only Japanese person who speak only Japanese

Page 6: Data Communication & Networking

Direction of Data FlowDirection of Data Flow

Page 7: Data Communication & Networking

Data FlowData Flow SimplexSimplex

UnidirectionalUnidirectional As on a one-way streetAs on a one-way street Ex: Keyboard, MonitorEx: Keyboard, Monitor

Half-duplexHalf-duplex Both transmit and receive possible, but not at the same timeBoth transmit and receive possible, but not at the same time Like a one-lane road with two-directional trafficLike a one-lane road with two-directional traffic Walkie-talkieWalkie-talkie

Full-duplex (Duplex)Full-duplex (Duplex) Transmit and receive simultaneouslyTransmit and receive simultaneously Like a two-way street, telephone networkLike a two-way street, telephone network Channel capacity must be divided between two directionsChannel capacity must be divided between two directions

Page 8: Data Communication & Networking

NetworkNetwork

Network: A set of devices (nodes) connected by communication linksNetwork: A set of devices (nodes) connected by communication links Node: Computer, printer, or any device capable of sending and/or Node: Computer, printer, or any device capable of sending and/or

receiving datareceiving data To be considered effective and efficient, a network must meet a To be considered effective and efficient, a network must meet a

number of criterianumber of criteria

Page 9: Data Communication & Networking

NetworkNetwork Performance : can be measure by transit time & Response time.Performance : can be measure by transit time & Response time.

Transit time is the amount of time required for a message to travel from one device to Transit time is the amount of time required for a message to travel from one device to

another.another.

Response Time: is the elapsed time between an inquiry and response.Response Time: is the elapsed time between an inquiry and response.

Performance depends up number of users ,types of transmission medium, capacity of Performance depends up number of users ,types of transmission medium, capacity of

hardware, efficiency of the softwarehardware, efficiency of the software

Performance also evaluated using Performance also evaluated using Throughput and DelayThroughput and Delay

Network throughput is the average rate of successful message delivery over a Network throughput is the average rate of successful message delivery over a

communication channel.communication channel. The throughput is usually measured in The throughput is usually measured in bits per second (bit/s per second (bit/s

or bps), and sometimes in or bps), and sometimes in data packets per second or data packets per per second or data packets per time slot. .

Page 10: Data Communication & Networking

NetworkNetwork

Reliability : can be measure frequency of failure, the time it takes a Reliability : can be measure frequency of failure, the time it takes a

link to recover from failure.link to recover from failure.

Security: It include protecting data from unauthorized access, Security: It include protecting data from unauthorized access,

protecting data from damage and development and implementing protecting data from damage and development and implementing

policies and procedures for recovery from breaches and data policies and procedures for recovery from breaches and data

losses.losses.

Page 11: Data Communication & Networking

Uses of Computer NetworksUses of Computer Networks

Business ApplicationsBusiness Applications Home ApplicationsHome Applications Mobile UsersMobile Users Social IssuesSocial Issues

Page 12: Data Communication & Networking

Uses of Computer NetworksUses of Computer NetworksBusiness ApplicationsBusiness Applications Many companies have a substantial number of Many companies have a substantial number of

computerscomputers the issue here is resource sharing, and the goal the issue here is resource sharing, and the goal

is to make all programs, equipment, and is to make all programs, equipment, and especially data available to anyone on the especially data available to anyone on the network without regard to the physical location network without regard to the physical location of the resource and the user. of the resource and the user.

An example is having a group of office workers An example is having a group of office workers share a common printer, scanners, and CD share a common printer, scanners, and CD burnersburners

more important, is sharing informationmore important, is sharing information

Page 13: Data Communication & Networking

Uses of Computer NetworksUses of Computer NetworksBusiness ApplicationsBusiness Applications Most companies have customer records, Most companies have customer records,

inventories, accounts receivable, financial inventories, accounts receivable, financial statements, tax information, and much more statements, tax information, and much more online.online.

If all of its computers went down, a bank could If all of its computers went down, a bank could not last more than five minutes. A modern not last more than five minutes. A modern manufacturing plant, with a computer-controlled manufacturing plant, with a computer-controlled assembly line, would not last even that long. Even assembly line, would not last even that long. Even a small travel agency or three-person law firm is a small travel agency or three-person law firm is now highly dependent on computer networks for now highly dependent on computer networks for allowing employees to access relevant information allowing employees to access relevant information and documents instantly.and documents instantly.

Page 14: Data Communication & Networking

Uses of Computer NetworksUses of Computer NetworksBusiness ApplicationsBusiness Applications Most companies have customer records, Most companies have customer records,

inventories, accounts receivable, financial inventories, accounts receivable, financial statements, tax information, and much more statements, tax information, and much more online.online.

If all of its computers went down, a bank could If all of its computers went down, a bank could not last more than five minutes. A modern not last more than five minutes. A modern manufacturing plant, with a computer-controlled manufacturing plant, with a computer-controlled assembly line, would not last even that long. Even assembly line, would not last even that long. Even a small travel agency or three-person law firm is a small travel agency or three-person law firm is now highly dependent on computer networks for now highly dependent on computer networks for allowing employees to access relevant information allowing employees to access relevant information and documents instantly.and documents instantly.

Page 15: Data Communication & Networking

Business Applications of Business Applications of NetworksNetworks

A network with two clients and one server.A network with two clients and one server.

Page 16: Data Communication & Networking

Business Applications of Networks Business Applications of Networks as Communication Mediumas Communication Medium

A computer network can provide a powerful communication medium among employees.

Virtually every company that has two or more computers now has e-mail (electronic mail)

Yet another form of computer-assisted communication is videoconferencing

A third goal for increasingly many companies is doing business electronically with other companies

A fourth goal that is starting to become more important is doing business with consumers over the Internet. Called e-commerce

Page 17: Data Communication & Networking

Business Applications of Business Applications of Networks as Communication Networks as Communication

MediumMedium The client-server model involves requests The client-server model involves requests

and replies.and replies.

Page 18: Data Communication & Networking

Home Network ApplicationsHome Network Applications

• Access to remote informationAccess to remote information• It can be surfing the World Wide Web for It can be surfing the World Wide Web for

information or just for fun. information or just for fun. • Information available includes the arts, Information available includes the arts,

business, cooking, government, health, business, cooking, government, health, history, hobbies, recreation, science, sports, history, hobbies, recreation, science, sports, travel, and many others.travel, and many others...

• Person-to-person communicationPerson-to-person communication• Interactive entertainmentInteractive entertainment• Electronic commerceElectronic commerce

Page 19: Data Communication & Networking

Home Network ApplicationsHome Network Applications

• Person-to-person communicationPerson-to-person communication• instant messaging, chat roominstant messaging, chat room• peer-to-peer communication-In this peer-to-peer communication-In this

form, individuals who form a loose form, individuals who form a loose group can communicate with others in group can communicate with others in the groupthe group

• Interactive entertainmentInteractive entertainment• Electronic commerceElectronic commerce

Page 20: Data Communication & Networking

Home Network Applications Home Network Applications (2)(2)

In peer-to-peer system there are no fixed In peer-to-peer system there are no fixed clients and servers.clients and servers.

Page 21: Data Communication & Networking

Home Network Applications Home Network Applications (3)(3)

Some forms of e-commerce.Some forms of e-commerce.

Page 22: Data Communication & Networking

Type of ConnectionType of Connection A network is two or more devices connected through link. A A network is two or more devices connected through link. A

link is communication pathway that transfer data from one link is communication pathway that transfer data from one device to another. Two types connectiondevice to another. Two types connection

Point-to-pointPoint-to-point Dedicated link between two devicesDedicated link between two devices The entire capacity of the channel is reservedThe entire capacity of the channel is reserved Ex) Microwave link, TV remote control Ex) Microwave link, TV remote control

Multipoint also called Multidrop Multipoint also called Multidrop More than two devices share a single linkMore than two devices share a single link Capacity of the channel is eitherCapacity of the channel is either

• Spatially sharedSpatially shared: Several Devices can use the link : Several Devices can use the link simultaneouslysimultaneously

• TimeshareTimeshare: Users take turns: Users take turns

Page 23: Data Communication & Networking

Type of ConnectionType of Connection

Page 24: Data Communication & Networking

Physical TopologyPhysical Topology It refers to the way in which a network is laid out It refers to the way in which a network is laid out

physically.physically. Two or more devices connect to a link; two or more link Two or more devices connect to a link; two or more link

form a topology.form a topology. The topology of a network is the geometric The topology of a network is the geometric

representation of the relationship of all the links and representation of the relationship of all the links and linking device to one another.linking device to one another.

Four basic topologies: Mesh, Star, Bus, RingFour basic topologies: Mesh, Star, Bus, Ring

Page 25: Data Communication & Networking

Mesh TopologyMesh Topology

Page 26: Data Communication & Networking

Mesh TopologyMesh Topology Every device has a dedicated point-to-point link to every other device.Every device has a dedicated point-to-point link to every other device.

To find the number of physical link in a fully connected mesh network To find the number of physical link in a fully connected mesh network

with n nodes.with n nodes.

Each nodes must be connected to every other nodes. Nodes 1 must be Each nodes must be connected to every other nodes. Nodes 1 must be

connected to n-1 nodes, nodes 2 connected to n-1 and finally node n connected to n-1 nodes, nodes 2 connected to n-1 and finally node n

must connected to n-1 nodes.must connected to n-1 nodes.

We need n(n-1) physical link.We need n(n-1) physical link.

However if each physical link allows communication in both direction However if each physical link allows communication in both direction

we can divide the number of link by 2 we can divide the number of link by 2

A mesh network with A mesh network with nn nodes has nodes has n(n-1)/2n(n-1)/2 links. links.

Page 27: Data Communication & Networking

Mesh TopologyMesh Topology Advantages:Advantages:

Use of dedicated links guarantees that each connection can carry its own data Use of dedicated links guarantees that each connection can carry its own data

load. Thus no traffic problems, load. Thus no traffic problems,

Robust If one link become unusable, it does not incapacitate the entire system.Robust If one link become unusable, it does not incapacitate the entire system.

Security, only intended recipient see the message Security, only intended recipient see the message

Easy fault identificationEasy fault identification & isolation & isolation

Disadvantages:Disadvantages:

Amount of cabling and the number of port required. Amount of cabling and the number of port required.

Every device must be connected to every device therefore difficult Every device must be connected to every device therefore difficult

installation/reconfiguration, space, costinstallation/reconfiguration, space, cost

Page 28: Data Communication & Networking

Star TopologyStar Topology Dedicated point-to-point link Dedicated point-to-point link only toonly to a central controller, called a a central controller, called a hubhub Devices are not directly linked to one another. Devices are not directly linked to one another. Hub acts as an exchange: No direct traffic between devicesHub acts as an exchange: No direct traffic between devices Advantages: Less expensive, robust, easy to install and reconfigureAdvantages: Less expensive, robust, easy to install and reconfigure Disadvantages: dependency of the whole on one single point, the hubDisadvantages: dependency of the whole on one single point, the hub Example LAN Example LAN

Page 29: Data Communication & Networking

Bus TopologyBus Topology One long cable that links all nodesOne long cable that links all nodes Nodes are connected to the bus cable by tap and drop line Nodes are connected to the bus cable by tap and drop line As signal travels along the backbone some of its energy is transferred into heat. As signal travels along the backbone some of its energy is transferred into heat.

Therefore there is limit on the number taps a bus can support and on the distance Therefore there is limit on the number taps a bus can support and on the distance between those tapsbetween those taps

Advantages: Easy installation, cheapAdvantages: Easy installation, cheap Disadvantages: Difficult reconfiguration, no fault isolation, a fault or break in the bus Disadvantages: Difficult reconfiguration, no fault isolation, a fault or break in the bus

stops all transmissionstops all transmission

Page 30: Data Communication & Networking

Ring TopologyRing Topology Dedicated point-to-point link only with the two nodes on each sidesDedicated point-to-point link only with the two nodes on each sides A signal is passed along the ring in one direction, from device to device, A signal is passed along the ring in one direction, from device to device,

until it reaches its destination.until it reaches its destination. Each device in the ring incorporate a repeater.Each device in the ring incorporate a repeater. Advantages: Easy reconfiguration, fault isolationAdvantages: Easy reconfiguration, fault isolation Disadvantage: Unidirectional traffic, a break in the ring cab disable the Disadvantage: Unidirectional traffic, a break in the ring cab disable the

entire networkentire network

Page 31: Data Communication & Networking

Hybrid TopologyHybrid Topology Example: Main star topology with each branch connecting several stations in Example: Main star topology with each branch connecting several stations in

a bus topologya bus topology To share the advantages from various topologiesTo share the advantages from various topologies

Page 32: Data Communication & Networking

Hybrid TopologyHybrid Topology

Page 33: Data Communication & Networking

Categories of NetworksCategories of Networks

Page 34: Data Communication & Networking

LANLAN Usually privately ownedUsually privately owned A network for a single office, building, or campus A network for a single office, building, or campus a few Km a few Km Common LAN topologies: bus, ring, starCommon LAN topologies: bus, ring, star An isolated LAN connecting 12 computers to a hub in a closetAn isolated LAN connecting 12 computers to a hub in a closet

Page 35: Data Communication & Networking

MANMAN Designed to extend to an entire cityDesigned to extend to an entire city Cable TV network, a company’s connected LANsCable TV network, a company’s connected LANs Owned by a private or a public companyOwned by a private or a public company

Page 36: Data Communication & Networking

WANWAN Long distance transmission, e.g., a country, a continent, the worldLong distance transmission, e.g., a country, a continent, the world Enterprise network: A WAN that is owned and used by one companyEnterprise network: A WAN that is owned and used by one company

Page 37: Data Communication & Networking

Wired Network Transmission MediaWired Network Transmission Media Twisted-pair cable Twisted-pair cable

Pairs of wires twisted togetherPairs of wires twisted together Used for telephone and network Used for telephone and network

connectionsconnections Coaxial cableCoaxial cable

Thick center wireThick center wire Used for computer networks, short-run Used for computer networks, short-run

telephone transmissions, cable television telephone transmissions, cable television deliverydelivery

Fiber-optic cableFiber-optic cable Glass or fiber strands through which light Glass or fiber strands through which light

can passcan pass Used for high-speed communicationsUsed for high-speed communications

Page 38: Data Communication & Networking

Wired Network Transmission MediaWired Network Transmission Media

Page 39: Data Communication & Networking

InternetworkInternetwork

Internetwork (internet) : two or more networks are Internetwork (internet) : two or more networks are connected by internetworking devicesconnected by internetworking devices

Internetworking devices: router, gateway, etc.Internetworking devices: router, gateway, etc. The Internet: a specific worldwide networkThe Internet: a specific worldwide network

Page 40: Data Communication & Networking

The InternetThe Internet The Internet has revolutionized many aspects of our daily lives. It The Internet has revolutionized many aspects of our daily lives. It

has affected the way we do business as well as the way we has affected the way we do business as well as the way we

spend our leisure time. The Internet is a communication system spend our leisure time. The Internet is a communication system

that has brought a wealth of information to our fingertips and that has brought a wealth of information to our fingertips and

organized it for our use.organized it for our use.

1967: ARPANET proposed by DoD’s ARPA(Advanced Research Project 1967: ARPANET proposed by DoD’s ARPA(Advanced Research Project

Agency)Agency)

1969: ARPANET in a reality: UCLA, UCSB, SRI, U. of Utah1969: ARPANET in a reality: UCLA, UCSB, SRI, U. of Utah

1973: Vint Cerf and Bob Kahn propose TCP, 1973: Vint Cerf and Bob Kahn propose TCP,

To split TCP into two protocols TCP and IPTo split TCP into two protocols TCP and IP

Page 41: Data Communication & Networking

Internet Internet TodayToday

• ISP (Internet service providers)

• NISP (national ISP)

• NAP (network access point)

Page 42: Data Communication & Networking

ProtocolsProtocols Protocol : ruleProtocol : rule

A set of rules that govern data communicationA set of rules that govern data communication For communication to occur, entities must agree upon a protocolFor communication to occur, entities must agree upon a protocol A protocol define what is communicated, how it is A protocol define what is communicated, how it is

communicated, and when it is communicatedcommunicated, and when it is communicated.. Key elements of a protocolKey elements of a protocol

Syntax: structure or format of dataSyntax: structure or format of data Semantics: meaning of each section of bits. How is a particular Semantics: meaning of each section of bits. How is a particular

pattern to be interpreted,& what action is to be taken based on pattern to be interpreted,& what action is to be taken based on that interpretation?.that interpretation?.

Timing: Timing: whenwhen and and how fasthow fast data should be sent data should be sent

Page 43: Data Communication & Networking

Standards: agreed-upon rulesStandards: agreed-upon rules Standards is essential inStandards is essential in

Creating/maintaining open and competitive markets for equipment Creating/maintaining open and competitive markets for equipment

manufacturersmanufacturers

Guaranteeing national/international interoperability of data & technologyGuaranteeing national/international interoperability of data & technology

Two categoriesTwo categories

De jure (“by law” or “by regulation’) standardsDe jure (“by law” or “by regulation’) standards

De facto (“by fact” or ‘by convention’) standardsDe facto (“by fact” or ‘by convention’) standards

• Proprietary standards: closed standardsProprietary standards: closed standards

• Nonproprietary standards: open standardsNonproprietary standards: open standards

Page 44: Data Communication & Networking

Standards OrganizationsStandards Organizations Standards are developed byStandards are developed by

Standards creation committeesStandards creation committees ForumsForums Regulatory agenciesRegulatory agencies

Standards committees & forumsStandards committees & forums Standards committees are slow movingStandards committees are slow moving Forums are made up of interested corporationsForums are made up of interested corporations Forum are able to speed acceptance of a Forum are able to speed acceptance of a

particular technologyparticular technology

Page 45: Data Communication & Networking

Standards CommitteesStandards Committees

ISO( International Organisation for Standardization)ISO( International Organisation for Standardization) Voluntary international organization Voluntary international organization

ITU-T ( International Telecommunication Union- ITU-T ( International Telecommunication Union- Telecommunication standards SectorTelecommunication standards Sector

Formerly, CCITT (Consultative Committee for International Formerly, CCITT (Consultative Committee for International Telegraphy & Telephony formed by UNTelegraphy & Telephony formed by UN

ANSI ( American National Standards Institute)ANSI ( American National Standards Institute) Private non-profit corporation in the USPrivate non-profit corporation in the US

IEEE( Institute of electrical & electronic engg.)IEEE( Institute of electrical & electronic engg.) The largest engineering society in the worldThe largest engineering society in the world

EIA( electronic Industries AssociationEIA( electronic Industries Association Non-profit organization in the USNon-profit organization in the US

Page 46: Data Communication & Networking

Internet StandardsInternet Standards

IETF (Internet Engineering Task Force)IETF (Internet Engineering Task Force) Internet DraftInternet Draft

working document with no official statusworking document with no official status with a 6-month lifetimewith a 6-month lifetime

RFC (Request for Comment)RFC (Request for Comment) Edited, assigned a number, and made Edited, assigned a number, and made

available to all interested partiesavailable to all interested parties