Networking Fundamentals © Ed Green Penn State University

Networking Networking FundamentalsFundamentals

© Ed Green© Ed Green Penn State UniversityPenn State University All Rights ReservedAll Rights Reserved

04/12/2304/12/23 Networking FundamentalsNetworking Fundamentals 22

AgendaAgenda ObjectivesObjectives Basic Terms and ConceptsBasic Terms and Concepts Network TopologiesNetwork Topologies DevicesDevices Network ArchitecturesNetwork Architectures MessagesMessages


ObjectivesObjectives Introduce Introduce networks networks and and networkingnetworking

as conceptsas concepts Introduce common network typesIntroduce common network types Introduce different types of network Introduce different types of network

devicesdevices Introduce different types of network Introduce different types of network

architecturesarchitectures Introduce messages and message Introduce messages and message

structuresstructures


Networks and Networks and NetworkingNetworking NetworkNetwork - a group of interconnected - a group of interconnected

computerscomputers. Networks may be . Networks may be classified according to a wide variety classified according to a wide variety of characteristics. of characteristics. (Source: (Source: www.wikipedia.orgwww.wikipedia.org ) )

PAN – Personal Area NetworkPAN – Personal Area Network LAN – Local Area NetworkLAN – Local Area Network MAN – Metropolitan Area NetworkMAN – Metropolitan Area Network WAN – Wide Area NetworkWAN – Wide Area Network

NetworkingNetworking – the set of processes and – the set of processes and devices involved in the use of a devices involved in the use of a networknetwork


Classifying NetworksClassifying Networks Network typesNetwork types

OpenOpen Network – a network that exists in the public Network – a network that exists in the public space space

Based on designs existing in the public domainBased on designs existing in the public domain Available to everyoneAvailable to everyone

ClosedClosed Network – a network that exists Network – a network that exists onlyonly in a in a non-public spacenon-public space

Proprietary – available to authenticated usersProprietary – available to authenticated users May or may not be based on designs existing in May or may not be based on designs existing in

public domainpublic domain StandardsStandards

TCP/IPTCP/IP EthernetEthernet


Classifying Networks - Classifying Networks - TopologyTopology Bus TopologyBus Topology Star TopologyStar Topology

Distinction Distinction Not representationNot representation Communications techniqueCommunications technique


Methods of Methods of CommunicationCommunication Bus TopologyBus Topology

From source to From source to destinationdestination

Star TopologyStar Topology

Through a central Through a central computer (computer (access point)access point)


ProtocolsProtocols Set of rules governing activities on a networkSet of rules governing activities on a network Purpose – promote compatibility of network applications Purpose – promote compatibility of network applications

using products from different vendors.using products from different vendors. Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with Collision Detection

(CSMA/CD) – bus topology(CSMA/CD) – bus topology Dictates that a message Dictates that a message must bemust be broadcast to every other broadcast to every other

machine on the networkmachine on the network Process –Process –

Wait for inactivity on the busWait for inactivity on the bus Dispatch messageDispatch message

Carrier Sense Multiple Access with Collision Avoidance Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) – star topology(CSMA/CA) – star topology Encompassed by IEEE 802.11 standards <WiFi>Encompassed by IEEE 802.11 standards <WiFi> Dispatch messages when readyDispatch messages when ready Retransmit when collisions occurRetransmit when collisions occur Give advantage to machines in waitGive advantage to machines in wait

Finds silent channel; Finds silent channel; Waits for a period of time; Waits for a period of time; Then transmitsThen transmits


Networking DevicesNetworking Devices Repeater – a device that passes signals back and Repeater – a device that passes signals back and

forth between two bussesforth between two busses Bridge – a device that passes signals back and forth Bridge – a device that passes signals back and forth

between two busses based on identified destination between two busses based on identified destination of messagesof messages

Switch – a bridge with multiple connections that Switch – a bridge with multiple connections that passes signals back and forth among several busses passes signals back and forth among several busses based on identified destination of messagesbased on identified destination of messages

Router – a special purpose computer used for Router – a special purpose computer used for forwarding messagesforwarding messages

iinternet – a network of networks; not nternet – a network of networks; not IInternetnternet Forwarding Table – a structure held by the network Forwarding Table – a structure held by the network

manager that keeps track of where each message manager that keeps track of where each message has been forwardedhas been forwarded

Gateway – internet connection pointGateway – internet connection point


Inter-process Inter-process CommunicationsCommunications The interchange of information The interchange of information

between two processesbetween two processes Clearly defined and described interfaceClearly defined and described interface Exchange of data between two processing Exchange of data between two processing

entitiesentities ConversationConversation

Message sent/acknowledgedMessage sent/acknowledged Response replied/acknowledgedResponse replied/acknowledged

Process 1Process 1 Process 2Process 2

Initiating MessageInitiating Message

Acknowledgement Acknowledgement

Reply MessageReply Message

Acknowledgement Acknowledgement


Inter-process Inter-process Communications ModelsCommunications Models Client/serverClient/server

Client – the process making the requestClient – the process making the request Server – the process satisfying the requestServer – the process satisfying the request

Peer-to-peerPeer-to-peer Processes that receive and satisfy requests for Processes that receive and satisfy requests for

each othereach other

Server Server serves many serves many clientsclients

Communicate as equals on a one – to – one basisCommunicate as equals on a one – to – one basis


Client/Server Client/Server ConsiderationsConsiderations

WorkstationWorkstationClientsClients

ProcessingProcessingServerServer

DeviceDeviceServersServers

PrinterPrinter

FilesFiles

NetworkNetwork


Client/Server Client/Server ConsiderationsConsiderations Thin/Thick – refers to the relative amount of Thin/Thick – refers to the relative amount of

processing that occurs on the deviceprocessing that occurs on the device Thin client – handles I/O operations for HCI and Thin client – handles I/O operations for HCI and

little other processinglittle other processing Thick client – handles a significant amount of Thick client – handles a significant amount of

processing in addition to I/O operations for HCIprocessing in addition to I/O operations for HCI Process Server – emphasizes executing Process Server – emphasizes executing

processing instructionsprocessing instructions Print Server – handles all requirements for Print Server – handles all requirements for

hard copy outputhard copy output File Server – handles all requirements File Server – handles all requirements

regarding access to stored dataregarding access to stored data Network Server – handles all requirements Network Server – handles all requirements

regarding communications servicesregarding communications services


Distributed SystemsDistributed Systems Multiple serversMultiple servers Applications execute on more than one serverApplications execute on more than one server Perhaps multiple physical locationsPerhaps multiple physical locations

Mainframe Router

LocalServers

Router

Local ServersWith Clients


Network Connectivity – An Network Connectivity – An Enterprise IT FrameworkEnterprise IT Framework

Application Integrator

. . .. . .

. . .. . .

User Interface

SecuritySecurity

ClientsClients

IndependentIndependentApplicationsApplications

Software thatSoftware thatprovides “commonprovides “commonview” capabilityview” capability

•AuthenticationAuthentication•AuthorizationAuthorization

WEB BrowserWEB Browser

•FinanceFinance•ManufacturingManufacturing•Sales/MarketingSales/Marketing•PersonnelPersonnel•EngineeringEngineering


e-World Concept of e-World Concept of OperationsOperations e-Process begins with a e-Process begins with a

buyer and a sellerbuyer and a seller Goods/services wanted Goods/services wanted

and availableand available GLOBAL EXCHANGE GLOBAL EXCHANGE

facilitates the electronic facilitates the electronic transactiontransaction

Seller’s catalog reviewed Seller’s catalog reviewed by buyerby buyer Needed items availableNeeded items available

Purchase order prepared Purchase order prepared and transmitted to and transmitted to global exchangeglobal exchange

Global exchange routes Global exchange routes to sellerto seller

Order entry preparedOrder entry prepared

Production schedule Production schedule established or updatedestablished or updated

Inventory checked; Inventory checked; replenishment orderedreplenishment ordered

Manufacturing resources Manufacturing resources assignedassigned

Labor availability checkedLabor availability checked Resources assignedResources assigned

OR ORHR to staff preparedHR to staff prepared

Sub-assemblies and other Sub-assemblies and other resources reservedresources reserved

Production package Production package preparedprepared Bill of materialsBill of materials Manufacturing/assembly Manufacturing/assembly

instructionsinstructions Drawings/blueprintsDrawings/blueprints


e-World Concept of e-World Concept of OperationsOperations (continued) (continued)

Production process is Production process is monitoredmonitored

Labor time & attendance Labor time & attendance is recordedis recorded

Test results and quality Test results and quality analysis recordedanalysis recorded

Shipping is scheduledShipping is scheduled Customer Service is Customer Service is

advisedadvised Billing is notifiedBilling is notified

Customer billing is Customer billing is preparedprepared

Order is shippedOrder is shipped

Order is receivedOrder is received Receiving inspection Receiving inspection

conducted; test results conducted; test results recordedrecorded

Bill is receivedBill is received Payment is madePayment is made Questions ariseQuestions arise Supplier customer Supplier customer

service is contactedservice is contacted Call is recordedCall is recorded Question is researched Question is researched

in the product reference in the product reference materialsmaterials

Answer is providedAnswer is provided


Enterprise Inter-Enterprise Inter-connectivityconnectivity


. . .. . .

. . .. . .User Interface

SecuritySecurity


. . .. . .


SecuritySecurity


. . .. . .


SecuritySecurity


. . .. . .


SecuritySecurityApplication Integrator

. . .. . .


SecuritySecurity


MessagesMessages Basic unit of communication on a Basic unit of communication on a

networknetwork Defined structureDefined structure


Message StructureMessage Structure

Message HeaderMessage Header Includes destinationIncludes destination Identifies sourceIdentifies source Identifies message (type)Identifies message (type)

Message TrailerMessage Trailer Indicates end of messageIndicates end of message

Message ContentsMessage Contents Must be defined in such a way that Must be defined in such a way that it is understood by it is understood by BOTHBOTH sender sender ANDAND receiver receiver


Messaging Infrastructure – Messaging Infrastructure – Message Format Message Format

AbstractionAbstractionDestination

Delivery Mode

Message ID

Timestamp

Correlation ID

Reply To

Redelivered

Type

Expiration

Priority

Message Properties


Network ArchitectureNetwork Architecture


Network Architecture – Network Architecture – Backbone of the Backbone of the

ArchitectureArchitecture Explains the communications configurationExplains the communications configuration

What elements will be used for communication?What elements will be used for communication? Defines the topology of the architectureDefines the topology of the architecture

Where will these communications elements be Where will these communications elements be located?located?

Describes the routingDescribes the routing How will data get from one node to the next?How will data get from one node to the next? Considers alternativesConsiders alternatives

Transportation modelTransportation model Addresses protocolsAddresses protocols

What is the communications mechanism?What is the communications mechanism? Are multiple protocols used and is translation Are multiple protocols used and is translation

needed?needed?


Transportation ModelTransportation Model ““Import” from Operations ResearchImport” from Operations Research

Developed originally to optimize routing of freight Developed originally to optimize routing of freight hauling vehicles (trains and trucks)hauling vehicles (trains and trucks)

Represents a realistic algorithm set that directs Represents a realistic algorithm set that directs transports to the path of least obstructiontransports to the path of least obstruction

Minimum TrafficMinimum Traffic Minimum delaysMinimum delays

ExampleExample A shipment of Volkswagens arrives at the Port of A shipment of Volkswagens arrives at the Port of

Baltimore. These cars are to be shipped to various Baltimore. These cars are to be shipped to various locations across the United States, including locations across the United States, including Pittsburgh, Fort Wayne, Kansas City, Denver, and Pittsburgh, Fort Wayne, Kansas City, Denver, and Missoula. What is the optimal route?Missoula. What is the optimal route?

At each city, what is the best route to the next stop At each city, what is the best route to the next stop based on all routing conditions? based on all routing conditions?

TrafficTraffic ConstructionConstruction WeatherWeather


Applying the Applying the Transportation ModelTransportation Model

NORNENORNE, a large energy services company, , a large energy services company, has business centers located in Baltimore, has business centers located in Baltimore, Pittsburgh, Fort Wayne, Kansas City, Pittsburgh, Fort Wayne, Kansas City, Denver, and Missoula. Payroll for the Denver, and Missoula. Payroll for the entire company is processed at the entire company is processed at the Baltimore computer center. Individual Baltimore computer center. Individual time and attendance data is collected for time and attendance data is collected for employees at individual locations and then employees at individual locations and then forwarded to Baltimore. Since payroll is a forwarded to Baltimore. Since payroll is a time critical application, time and time critical application, time and attendance data must arrive in a timely attendance data must arrive in a timely manner.manner.



Which route will the data take?



Route not predictable in advance Route not predictable in advance Will vary based on conditionsWill vary based on conditions

Will follow “path of least resistance”Will follow “path of least resistance” ALLALL network managers work to minimize network managers work to minimize

latency and maximize throughputlatency and maximize throughput Data will depart from a given node Data will depart from a given node withwith

Next node identifiedNext node identified General itineraryGeneral itinerary

General itinerary identified upon arrival at General itinerary identified upon arrival at each destinationeach destination Routing re-planned should conditions warrantRouting re-planned should conditions warrant


Components of Network Components of Network ArchitecturesArchitectures

Routers – a physical or logical device that Routers – a physical or logical device that determines the next network point to which determines the next network point to which a packet should be forwardeda packet should be forwarded Connected to at least two networksConnected to at least two networks Decision based on current understanding of Decision based on current understanding of

network statenetwork state Table of routing alternatives and current Table of routing alternatives and current

conditionsconditions Located at any gatewayLocated at any gateway

Gateway – the place where one network or Gateway – the place where one network or network segment meets anothernetwork segment meets another

Switch – a physical or logical device that Switch – a physical or logical device that redirects a packet from one network redirects a packet from one network segment to anothersegment to another


Components of Network Components of Network ArchitectureArchitecture

Bandwidth – the capacity of a network Bandwidth – the capacity of a network measured in terms of throughput ratemeasured in terms of throughput rate Gigabits per Gigabits per secondsecond

TCP/IP communications language of TCP/IP communications language of the internetthe internet

Packet – the “data unit” that is Packet – the “data unit” that is transported from one node to anothertransported from one node to another


Network Architecture – Network Architecture – Showing the ComponentsShowing the Components

Mainframe Router

LocalServers

Router

Local ServersWith Clients


Network Architecture – Network Architecture – Showing the TopologyShowing the Topology

Mainframe Router

LocalServers

Router Local Servers

With Clients


Networks – Discussion Networks – Discussion ExampleExample

ISPISP

Local W

eb

Sit

es

Local W

eb

Sit

es

Track an Internet searchTrack an Internet search

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Networking Fundamentals © Ed Green Penn State University