networking & nms project

8/3/2019 networking & NMS project

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Project Report

On

Networking and NMS(Network Management Protocol)

In

Sai Infosystem (India) Ltd.

Submitted by:Adit Pareek

Er no:A20405108008

B.Tech (E&C), IV Semester

Under the Guidance of

Mr. Tejas Shah

L3 Engineer, NOC,

S.I.S. (India) Ltd.


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Amity School of Engineering

AMITY UNIVERSITY RAJASTHAN

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ACKNOWLEDGEMENT

I wish to express my gratitude to Mr. Tejas Shah (L3 Engineer, NOC- S.I.S. (India)Ltd.) and Ashutosh Tripathi (Professor, Amity Jaipur) under whose guidance I was

able to work, gain knowledge and understand Networking Systems and its

implementation.

I also want to thank entire N.O.C team of Sai Infosystems India Ltd. who all acted as

a sounding board all the time.

Adit Pareek

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1. INTRODUCTION

THEPROJECTGIVESABRIEFINTRODUCTIONTONETWORKANDTHE OSI LAYER MODEL .

ITALSOEXPLAINSTHE SNMP(SIMPLE NETWORKMANAGEMENT PROTOCOL ) INBRIEF ,

ITSAPPLICATION , NEED & UTILITY .

THEPROJECTALSOGIVESANINTRODUCTIONTO NOC(NETWORKOPERATIONS

CENTER ).THEPRACTICALWORKINGOFA NMS OPMANAGER ISALSOBEEN

EXPLAINED .

THEMETHODOLOGYADOPTEDFORPROJECTWORKISKNOWLEDGEBYEXPERIENCING ,

LEARNINGANDDISCUSSING.

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INTRODUCTIONTO ORGANIZATION

SAI INFOSYTEM (INDIA) LTD., IS A LARGEST

INFORMATION TECHNOLOGY (IT) COMPANY OF

GUJARAT HAVING A NATIONWIDE PRESENCE.

POPULARLY KNOWN AS A SIS, IS AN ISO

9001,ISO 14001 AND ISO 27001 CERTIFIED

COMPANYHAVINGAGROUPTURNOVEROFAROUND RS.

416 CRORES. SIS HAS PAN INDIA PRESENCE WITH

10 BRANCHOFFICESANDOVER 90 SUPPORTSERVICE

CENTERS, ONE MANUFACTURING UNIT AND HAVING ON

BOARD OVER 600+ IT PROFESSIONALS . SIS IS

MOVING GLOBAL STARTING OVERSEAS OPERATIONS IN

MIDDLE EAST.

SIS OFFERSTOTAL IT SOLUTIONTO VARIOUS GOVERNMENT AGENCIES, DEPARTMENT,

PSUS, STATE GOVERNMENTS AND CORPORATE AS WELL AS SCIENTIFIC INSTITUTIONSHAVING MORETHAN 600+ PROFESSIONALS ACROSSTHE INDIATO ENSURE RELIABLE,

EFFICIENTANDTIMELYSERVICESTOITSCUSTOMERS.

PROMOTED BY TECHNOCRAT-ENTREPRENEURS, SHRI SUNIL KAKKAD AND SHRI

VIJAY MANDORA, WHO ARE WELL EXPERIENCED IN THE FIELD OF INFORMATION

TECHNOLOGY, SIS WASORIGINALLYSET-UPIN 1992 ASAPROPRIETARYCONCERN AND

SUBSEQUENTLY ITWAS INCORPORATEDASAPRIVATELIMITED COMPANYON JANUARY 1,

2003 ANDLATERONCONVERTED INTOAPUBLICLIMITEDCOMPANYIN JANUARY 2008.

SIS ISINTHEBUSINESSOFASSEMBLINGANDTRADINGOF COMPUTERHARDWAREAND SOFTWARE, PROVIDING SYSTEM INTEGRATION SOLUTIONS AND RUNNING OF PC-

BASED GAMING STATIONS AND CALL CENTRE. IT ALSO PROVIDES AMC (ANNUAL

MAINTENANCE CONTRACTS) SERVICESFORITSCLIENTS. HOWEVER, THEBASICTHRUSTOF

SIS ITTO PROVIDETOTAL IT SOLUTION RATHERTHAN SUPPLY HARDWARE PRODUCTS.

SIS HAS ITSASSEMBLINGUNIT LOCATEDAT PARWANOO IN HIMACHAL PRADESHWHICH

ENJOYS FISCALBENEFITS (TAX EXEMPTIONS) WHICH ENABLESTHECOMPANYTO ENHANCE

THE COST COMPETITIVENESS OF ITS PRODUCTS. SIS PLANSTO ENTERTHE FIELD OF

TELECOMTHROUGHTHE LAUNCHOFVIDEOTELEPHONYSERVICE (VVOBB) ACROSSTHE

NORTHERN

AND

WESTERN

REGIONS

OF

INDIA

UNDER

FRANCHISEE

AGREEMENT

WITH

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BSNL. ITALSOHASPLANSTOPROVIDEDATACENTRESERVICESUNDERTIE-UPWITH ITI

LTD. ITALSOHASA 100% SUBSIDIARYCOMPANY, E-MALL INFOTECH PVT. LTD. (E-

MALL), WHICH IS RUNNING A CHAIN OF RETAIL ELECTRONIC STORES WITH OPERATIONS

MAINLYFOCUSEDIN GUJARAT.

SIS IS RANKED 7TH LARGEST COMPANY OF INDIA UNDER IT COMPANY

PROVIDINGCOMPLETESOLUTION CATEGORYFORYEAR 2006-07 BY DATA QUESTAND

WAS RANKED 15TH INYEAR 2005-06. RECENTLY SIS DESKTOPS GET REGISTERED

WITH DGS & D ALSO AND HAVE MANY INNOVATIVE SOLUTIONS AND AS WELL AS

ACHIEVEMENTSUNDEROURBELT.

SIS ISONEOFTHEFOUR ESAA (ENABLED SERVER ACCELERATION ALLIANCE)

PARTNERSOF INTELIN INDIA, ONEOFTHE 20 STAR PARTNERSOF MICROSOFT, LARGEST

CALL CENTER SOLUTION PROVIDER TO BSNL AS WELL AS LARGEST DOT SOFT

IMPLEMENTERFOR BSNL IN INDIA.SIS HASALSOBAGGEDTHESINGLELARGEST ORDER

FOR XEON BASED SERVERSIN ASIA PACIFICFOR INTEL.

SIS ISFOCUSEDONPROVIDINGTOTALSOLUTIONSTOFOUR BUSINESS VERTICALS

NAMELY TELECOM, POWER, DEFENSEANDE-GOVERNANCEFORSTATEGOVERNMENTSAND

PSUS. DURING SIS'SJOURNEY OF GROWTH IT HAD DEVELOPED MANY CUSTOMIZED

SOLUTIONS SUITABLETO EACH OFTHESE VERTICALS LIKE SYSTEM INTEGRATION, CALL

CENTER SOLUTIONS, WAN, THINCLIENTANDE-PROCUREMENT SOLUTIONS.

SIS BUSINESS INCLUDES TOTAL IT SOLUTIONS, TECHNOLOGY INTEGRATION,

MANUFACTURINGVARIOUSHARDWAREPRODUCTSLIKE SERVERS , DESKTOPS , LAPTOPS ,

NETWORKINGPRODUCTSANDMARKETINGTHEMUNDERBRAND SIS, RETAILINGOF IT

PRODUCTS WITH CHAIN OF FOCUSED IT MALLS E-MALL, PROVIDING WORLD CLASS CALL

CENTRE SOLUTIONS WITH EBRAIN, AND GAMINGTHRILLS WITH HIGH ENDTECHNOLOGY

BASEDWORKSTATIONSFROME-FUN.

SIS GROUP IS SERVING ENTIRE IT NEEDS , FROM LARGE IT PROJECTSTO GAMMINGSTATION FOR KIDS, FROM HARDWARE TO SOFTWARE, FROM GOVERNMENT TOINDIDIVIDUAL. ORGANISATIONOF SIS GROUP:

SIS IS THE FASTEST GROWING TOTAL INFORMATION TECHNOLOGY SOLUTION PROVIDINGCOMPANY OF GUJARAT, PROUD TO BE LEADING IN SYSTEM INTEGRATION, CALL CENTER

SOLUTIONS, CRM & E-PROCUREMENT IMPLEMENTATION AND ERP DEVELOPMENT PRESENT

ACROSS INDIA.

ACROSS INDIA, SIS HAVEDIRECTOPERATIONSIN 17 STATESANDEMPLOYMORE

THAN 600 ASSOCIATES. INADDITION, SIS REACHESCUSTOMERSWITHOWN IT

PRODUCTSRANGINGFROM PERSONAL COMPUTERS, LAPTOPS, SERVERS, POWER

PRODUCTS, NETWORKINGEQUIPMENTSETC.

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TOMEETTHEDEMANDFORTHE

PRODUCTS, SIS OPERATESTATE-OF-THE-ART

MANUFACTURINGAND

DISTRIBUTIONFACILITIESIN

PARWANOO (HIMACHAL

PRADESH), GOAAND JAIPUR.

ACROSS INDIA, SIS ISCOMMITTEDTOASSISTSITS

CUSTOMERSWITH ANNUAL MAINTENANCE CONTRACT

OFTHE SOFTWAREAND HARDWARESUPPORTEDROUND

THECLOCKBYPROMISINGRESIDENCE ENGINEERS. ITIS

THEIRDEDICATIONANDPASSIONOFPROTECTINGBRAND

THATHASMADE SIS THECOMPANYTHATITISTODAY.

SIS ISAKNOWNNAMEIN INDIAFOR INFORMATION

TECHNOLOGY SERVICESAND SOLUTIONS COMPANY

HAVINGPRESENCEACROSSIndia. We deliver theprecision thinking and relentless execution

that drives our clients' business

transformation.

* SIS Announces

First Video Phone

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2.1 PRODUCTS

SIS OFFERSAWIDERANGEOFPRODUCTSANDSERVICES INTHEAREAOF INFORMATION

TECHNOLOGY. THEIRPRODUCTSCANBECATEGORIZEDINTOTHEFOLLOWINGCATEGORIES.

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2.2 SERVICES

SIS OFFERINGCOMPLETERANGEOF IT AND COMMUNICATION SERVICESADDRESSESTHE NEEDS OF BOTHTECHNOLOGY AND BUSINESS REQUIREMENTSTO HELPORGANIZATIONSLEVERAGELEADING-EDGETECHNOLOGIESFORBUSINESSIMPROVEMENT.

SIS HELPORGANISATIONS INTHEIR IT NEEDSOFTHE ENTIRE ENTERPRISE. THESERVICES EXTENDS FROM SIMPLE OFFICE AUTOMATION TO ENTERPRISE APPLICATIONSERVICES LIKE CRM, E-PROCUREMENT,ERP, CALL CENTER SOLUTIONS. SISSENTERPRISESOLUTIONSHAVESERVEDANDCONTINUETOSERVECLIENTSFROMARANGEOFINDUSTRIES INCLUDING TELECOM , ENERGYAND UTILITIES IN GOVERNMENT, PSUSANDPRIVATESECTOR.

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2.3 ASSOCIATES

APC - FOR ENTIRE RANGEOF UPS

CANON - ENTIRE RANGEOF PRINERSAND SCANNERS

HP - FOR INTEL BASED AND RISC BASED HIGH ENDSERVERS , DESKTOPS AND LAPTOPS, PERIPHERALS AND

STORAGE DEVICES SOLUTIONS.

IBM - FOR INTEL BASED AND RISC BASED HIGH END

SERVERS, DESKTOPSAND LAPTOPS

INGRAM MICRO - TO SELL SUPPLY AND INSTAALL ENTIRE

RANGE OF MICROSOFT , CALDERA , ORACLE, AUTODESK,

SYMENTAC , IBM, LENOVEO, HP, ACER, HCL, EPSON,

TVSE, SUN ACCROSSTHECOUNTRY

INTEL - GENUINE INTEL DEALER, TOTAL RANGE OF

SERVERS & DESKTOPSOF SIS PRODUCTS.

INTEX - For Complete Range of Peripherals

LENOVO - FOR LENOVO BUSINESS PARTNER

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MICROSOFT - FOR NETWORK OPERATING SYSTEM, DESKTOPOPERATING SYSTEMS, SQL RDBMS AND OTHERDEVELOPMENT TOOLS.

ORACLE - DATABASEAND TOOLS

SUN - FOR RISC BASED HIGH END SERVER

MILESTONES

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NETWORKAND CONTACTDETAILS

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3.WHATISNETWORK ?

A COMPUTERNETWORK, OFTENSIMPLYREFERREDTOASANETWORK, ISA

COLLECTIONOFCOMPUTERSANDDEVICESCONNECTEDBYCOMMUNICATIONSCHANNELS

THATFACILITATESCOMMUNICATIONSAMONGUSERSANDALLOWSUSERSTOSHARE

RESOURCESWITHOTHERUSERS.

PURPOSE

COMPUTERNETWORKSCANBEUSEDFORSEVERALPURPOSES:

FACILITATINGCOMMUNICATIONS. USINGANETWORK, PEOPLECANCOMMUNICATEEFFICIENTLYANDEASILYVIAE-MAIL, INSTANTMESSAGING, CHATROOMS,TELEPHONE, VIDEOTELEPHONECALLS, ANDVIDEOCONFERENCING.

SHARINGHARDWARE. INANETWORKEDENVIRONMENT, EACHCOMPUTERONANETWORKCANACCESSANDUSEHARDWAREONTHENETWORK. SUPPOSESEVERALPERSONALCOMPUTERSONANETWORKEACHREQUIRETHEUSEOFALASERPRINTER. IFTHEPERSONALCOMPUTERSANDALASERPRINTERARECONNECTEDTOANETWORK, EACHUSERCANTHENACCESSTHELASERPRINTERONTHENETWORK,ASTHEYNEEDIT.

SHARINGFILES, DATA, ANDINFORMATION. INANETWORKENVIRONMENT, ANYAUTHORIZEDUSERCANACCESSDATAANDINFORMATIONSTOREDONOTHERCOMPUTERSONTHENETWORK. THECAPABILITYOFPROVIDINGACCESSTODATAANDINFORMATIONONSHAREDSTORAGEDEVICESISANIMPORTANTFEATUREOFMANYNETWORKS.

SHARINGSOFTWARE. USERSCONNECTEDTOANETWORKCANACCESSAPPLICATIONPROGRAMSONTHENETWORK

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4. TYPES OF NETWORK

LAN LOCAL AREA NETWORK IS A SMALL

GEOGRAPHICAL AREA SUCH AS OUR SCHOOL

BOARD.

MAN METROPOLITAN AREA NETWORK IS A

NETWORK OVER A LARGER GEOGRAPHICAL AREA

SUCH AS THE PROVINCIAL GOVERNMENT.

WAN WIDE AREA NETWORK IS A NETWORK USED

OVER AN EXTREMELY LARGE GEOGRAPHICAL AREA

SUCH AS THE FEDERAL GOVERNMENT

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5.BASIC NETWORK TOPOLOGIES

BUSNETWORK

STARNETWORK

RINGNETWORK

MESHNETWORK

5.1 BUS TOPOLOGY

A BUSNETWORKTOPOLOGYISANETWORKARCHITECTUREINWHICHASETOF

CLIENTSARECONNECTEDVIAASHAREDCOMMUNICATIONSLINE, CALLEDABUS

ADVANTAGES

EASYTOIMPLEMENTANDEXTEND. EASYTOINSTALL. WELL-SUITEDFORTEMPORARYORSMALLNETWORKSNOTREQUIRINGHIGHSPEEDS

(QUICKSETUP). CHEAPERTHANOTHERTOPOLOGIES. COSTEFFECTIVE; ONLYASINGLECABLEISUSED. EASYIDENTIFICATIONOFCABLEFAULTS.

REDUCEDWEIGHTDUETOFEWERWIRES.

DISADVANTAGES

LIMITEDCABLELENGTHANDNUMBEROFSTATIONS. IFTHEREISAPROBLEMWITHTHECABLE, THEENTIRENETWORKBREAKSDOWN. MAINTENANCECOSTSMAYBEHIGHERINTHELONGRUN. PERFORMANCEDEGRADESASADDITIONALCOMPUTERSAREADDEDORONHEAVY

TRAFFIC (SHAREDBANDWIDTH). PROPERTERMINATIONISREQUIRED (LOOPMUSTBEINCLOSEDPATH). SIGNIFICANT CAPACITIVE LOAD (EACHBUSTRANSACTIONMUSTBEABLETO

STRETCHTOMOSTDISTANTLINK).

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ITWORKSBESTWITHLIMITEDNUMBEROFNODES. SLOWERDATATRANSFERRATETHANOTHERTOPOLOGIES. ONLYONEPACKETCANREMAINONTHEBUSDURINGONECLOCKPULSE.

FIG: 2.2.1(BUSTOPOLOGY)

5.2 STAR TOPOLOGY

ASTARNETWORKCONSISTSOFONECENTRALSWITCH, HUBORCOMPUTER, WHICH

ACTSASACONDUITTOTRANSMITMESSAGES. THUS, THEHUBANDLEAFNODES,

ANDTHETRANSMISSIONLINESBETWEENTHEM, FORMAGRAPHWITHTHETOPOLOGY

OFASTAR

ADVANTAGES

BETTERPERFORMANCE: THESTARTOPOLOGYPREVENTSTHEPASSINGOFDATAPACKETSTHROUGHANEXCESSIVENUMBEROFNODES. ATMOST, 3 DEVICESAND2 LINKSAREINVOLVEDINANYCOMMUNICATIONBETWEENANYTWODEVICES.ALTHOUGHTHISTOPOLOGYPLACESAHUGEOVERHEADONTHECENTRALHUB,WITHADEQUATECAPACITY, THEHUBCANHANDLEVERYHIGHUTILIZATIONBYONEDEVICEWITHOUTAFFECTINGOTHERS.

ISOLATIONOFDEVICES: EACHDEVICEISINHERENTLYISOLATEDBYTHELINKTHATCONNECTSITTOTHEHUB. THISMAKESTHEISOLATIONOFINDIVIDUALDEVICES

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STRAIGHTFORWARDANDAMOUNTSTODISCONNECTINGEACHDEVICEFROMTHEOTHERS. THISISOLATIONALSOPREVENTSANYNON-CENTRALIZEDFAILUREFROMAFFECTINGTHENETWORK.

BENEFITSFROMCENTRALIZATION: ASTHECENTRALHUBISTHEBOTTLENECK,

INCREASINGITSCAPACITY, ORCONNECTINGADDITIONALDEVICESTOIT, INCREASESTHESIZEOFTHENETWORKVERYEASILY. CENTRALIZATIONALSOALLOWSTHEINSPECTIONOFTRAFFICTHROUGHTHENETWORK. THISFACILITATESANALYSISOFTHETRAFFICANDDETECTIONOFSUSPICIOUSBEHAVIOR.

SIMPLICITY: THISTOPOLOGYISEASYTOUNDERSTAND, ESTABLISH, ANDNAVIGATE.ITSSIMPLICITYOBVIATESTHENEEDFORCOMPLEXROUTINGORMESSAGEPASSINGPROTOCOLS. ALSO, ASNOTEDEARLIER, THEISOLATIONANDCENTRALIZATIONITALLOWSSIMPLIFYFAULTDETECTION, ASEACHLINKORDEVICECANBEPROBEDINDIVIDUALLY.

EASYTOINSTALLANDWIRE. EASYTODETECTFAULTSANDTOREMOVEPARTS. NODISRUPTIONSTOTHENETWORKWHENCONNECTINGORREMOVINGDEVICES.

DISADVANTAGES

THEPRIMARYDISADVANTAGEOFASTARTOPOLOGYISTHEHIGHDEPENDENCEOFTHESYSTEMONTHEFUNCTIONINGOFTHECENTRALHUB.

THEFAILUREOFTHECENTRALHUBRENDERSTHENETWORKINOPERABLE,IMMEDIATELYISOLATINGALLNODES.

NETWORKSIZEISLIMITEDBYTHENUMBEROFCONNECTIONSTHATCANBEMADETOTHEHUB, ANDPERFORMANCEFORTHEENTIRENETWORKISCAPPEDBYITSTHROUGHPUT.

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5.3 RING TOPOLOGY

A RINGNETWORKISANETWORKTOPOLOGYINWHICHEACHNODECONNECTSTO

EXACTLYTWOOTHERNODES, FORMINGASINGLECONTINUOUSPATHWAYFOR

SIGNALSTHROUGHEACHNODE - ARING. DATATRAVELSFROMNODETONODE,

WITHEACHNODEALONGTHEWAYHANDLINGEVERYPACKET

ADVANTAGES

VERYORDERLYNETWORKWHEREEVERYDEVICEHASACCESSTOTHETOKENANDTHEOPPORTUNITYTOTRANSMIT

PERFORMSBETTERTHANASTARTOPOLOGYUNDERHEAVYNETWORKLOAD CANCREATEMUCHLARGERNETWORKUSING TOKEN RING DOESNOTREQUIRENETWORKSERVERTOMANAGETHECONNECTIVITYBETWEEN

THECOMPUTERS

DISADVANTAGES

ONEMALFUNCTIONINGWORKSTATIONORBADPORTINTHE MAU CANCREATEPROBLEMSFORTHEENTIRENETWORK

MOVES, ADDSANDCHANGESOFDEVICESCANAFFECTTHENETWORK NETWORKADAPTERCARDSAND MAU'SAREMUCHMOREEXPENSIVETHAN

ETHERNETCARDSANDHUBS MUCHSLOWERTHANAN ETHERNETNETWORKUNDERNORMALLOAD

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5.4 MESH TOPOLOGY

MESHNETWORKINGISATYPEOFNETWORKINGWHEREINEACHNODEIN

THE NETWORKMAYACTASANINDEPENDENTROUTER, REGARDLESSOF

WHETHERITISCONNECTEDTOANOTHERNETWORKORNOT.

ITALLOWSFORCONTINUOUSCONNECTIONSANDRECONFIGURATIONAROUND

BROKENORBLOCKEDPATHSBY HOPPING FROMNODETONODEUNTILTHE

DESTINATIONISREACHED.

A MESHNETWORKWHOSENODESAREALLCONNECTEDTOEACHOTHERISA

FULLYCONNECTEDNETWORK.

FULLYCONNECTEDMESH mesh

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http://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_networkhttp://en.wikipedia.org/wiki/Fully_connected_network


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OSI MODEL (O.S.I. - OPEN SYSTEM

INTERCONNECTION)

THE O.S.I. MODEL (O.S.I. - OPEN SYSTEM INTERCONNECTION) ISA

WAYOFSUB-DIVIDINGA SYSTEMINTOSMALLERPARTS (CALLEDLAYERS)

FROMTHEPOINTOFVIEWOFCOMMUNICATIONS. AN OSI LAYERISA

COLLECTIONOFCONCEPTUALLYSIMILARFUNCTIONSTHATPROVIDESERVICES

TOTHELAYERABOVEITANDRECEIVESSERVICESFROMTHELAYERBELOWIT.

ANDITSUSEISTOPROVIDEA

COMMONPLATFORMFORCOMMUNICATIONSOTHATDIFFERENTDEVICESBY

DIFFERENT MANUFACTURERS CAN COMMUNICATEAMONGTHEM

SELVES.

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6.1 APPLICATION LAYER

APPLICATIONPROTOCOLSAREDEFINEDATTHISLAYER, WHICHIMPLEMENTSPECIFICUSERAPPLICATIONSANDOTHERHIGH-LEVELFUNCTIONS. SINCETHEYAREATTHETOPOFTHESTACK, APPLICATIONPROTOCOLSARETHEONLYONESTHATDONOTPROVIDESERVICESTOAHIGHERLAYER; THEYMAKEUSEOFSERVICESPROVIDEDBYTHELAYERSBELOW. ONEOFTHE APPLICATIONLAYERFUNCTIONISFILETRANSFERTHEAPPLICATIONLAYERISTHEONETHATISUSEDBYNETWORKAPPLICATIONS.THESEPROGRAMSAREWHATACTUALLYIMPLEMENTTHEFUNCTIONSPERFORMEDBYUSERSTOACCOMPLISHVARIOUSTASKSOVERTHENETWORK .THESEPROGRAMSAREWHATACTUALLYIMPLEMENTTHEFUNCTIONS

IT'SIMPORTANTTOUNDERSTANDTHATWHATTHE OSI MODELCALLSAN

APPLICATION ISNOTEXACTLYTHESAMEASWHATWENORMALLYTHINKOFAS

AN APPLICATION. INTHE OSI MODEL, THEAPPLICATIONLAYERPROVIDES

SERVICESFORUSERAPPLICATIONSTOEMPLOY. FOREXAMPLE, WHENYOUUSE

YOUR WEBBROWSER, THATACTUALSOFTWAREISANAPPLICATIONRUNNINGON

YOUR PC. ITDOESN'TREALLY RESIDE ATTHEAPPLICATIONLAYER. RATHER, IT

MAKESUSEOFTHESERVICESOFFEREDBYAPROTOCOLTHATOPERATESATTHE

APPLICATIONLAYER, WHICHISCALLEDTHE HYPERTEXT TRANSFER PROTOCOL

(HTTP).

SOMEOFTHEMOSTPOPULARAPPLICATIONLAYERPROTOCOLSARE:

HTTP: HYPERTEXT TRANSFER PROTOCOL HTTP ISAREQUEST-RESPONSEPROTOCOLSTANDARDFORCLIENT-SERVER COMPUTING

FTP: FILETRANSFERPROTOCOL ISASTANDARDNETWORKPROTOCOLUSEDTOCOPYAFILEFROMONEHOSTTOANOTHEROVERA TCP/IP-BASEDNETWORK, SUCHASTHEINTERNET.

SMTP: SIMPLE MAIL TRANSFER PROTOCOL ISAN INTERNETSTANDARDFOR

ELECTRONICMAIL (E-MAIL) TRANSMISSIONACROSS INTERNET PROTOCOL (IP) NETWORKS.

SNMP: SIMPLE NETWORKMANAGEMENT PROTOCOL ISA UDP-BASEDNETWORKPROTOCOL. ITISUSEDMOSTLYINNETWORKMANAGEMENTSYSTEMSTOMONITORNETWORK-ATTACHEDDEVICESFORCONDITIONSTHATWARRANTADMINISTRATIVEATTENTION.DHCP: DYNAMIC HOST CONFIGURATION PROTOCOL (DHCP) ISACOMPUTERNETWORKINGPROTOCOLUSEDBYHOSTS (DHCP CLIENTS) TORETRIEVE IP ADDRESSASSIGNMENTSANDOTHERCONFIGURATIONINFORMATION.

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http://en.wikipedia.org/wiki/Request-responsehttp://en.wikipedia.org/wiki/Request-responsehttp://en.wikipedia.org/wiki/Request-responsehttp://en.wikipedia.org/wiki/Request-responsehttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Client-serverhttp://en.wikipedia.org/wiki/Request-responsehttp://en.wikipedia.org/wiki/Client-server


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NFS: NETWORKFILE SYSTEMALLOWINGAUSERONACLIENTCOMPUTERTOACCESSFILESOVERANETWORKINAMANNERSIMILARTOHOWLOCALSTORAGEISACCESSED

TELNET: TELNET (TELE-NETWORK) ISANETWORKPROTOCOLUSEDONTHE

INTERNETORLOCALAREANETWORKSTOPROVIDEABIDIRECTIONALINTERACTIVETEXT-ORIENTEDCOMMUNICATIONSFACILITYVIAAVIRTUALTERMINALCONNECTION

NNTP : NETWORKNEWS TRANSFER PROTOCOL (NNTP) ISAN INTERNETAPPLICATIONPROTOCOLUSEDFORTRANSPORTING USENETNEWSARTICLES (NETNEWS)BETWEENNEWSSERVERSANDFORREADINGANDPOSTINGARTICLESBYENDUSERCLIENTAPPLICATIONS

6.2 PRESENTATION LAYER

ITDEALSWITHTHEPRESENTATIONOFDATA. MORESPECIFICALLY, THEPRESENTATIONLAYERISCHARGEDWITHTAKINGCAREOFANYISSUESTHATMIGHTARISEWHEREDATASENTFROMONESYSTEMNEEDSTOBEVIEWEDINADIFFERENTWAYBYTHEOTHERSYSTEM. ITALSOTAKESCAREOFANYSPECIALPROCESSINGTHATMUSTBEDONETODATAFROMTHETIMEANAPPLICATIONTRIESTOSENDITUNTILTHETIMEITISSENTOVERTHENETWORK

PRESENTATION LAYER FUNCTIONS

HEREARESOMEOFTHESPECIFICTYPESOFDATAHANDLINGISSUESTHATTHEPRESENTATIONLAYERHANDLES:

TRANSLATION: NETWORKSCANCONNECTVERYDIFFERENTTYPESOFCOMPUTERSTOGETHER: PCS, MACINTOSHES, UNIX SYSTEMS, AS/400 SERVERS ANDMAINFRAMESCANALLEXISTONTHESAMENETWORK. THESESYSTEMSHAVEMANYDISTINCTCHARACTERISTICSANDREPRESENTDATAINDIFFERENTWAYS; THEYMAYUSEDIFFERENTCHARACTERSETSFOREXAMPLE. THEPRESENTATIONLAYERHANDLESTHEJOBOFHIDINGTHESEDIFFERENCESBETWEENMACHINES.

COMPRESSION: COMPRESSION (ANDDECOMPRESSION) MAYBEDONEATTHEPRESENTATIONLAYERTOIMPROVETHETHROUGHPUTOFDATA. (THEREARESOMEWHOBELIEVETHISISNOT, STRICTLYSPEAKING, AFUNCTIONOFTHEPRESENTATIONLAYER.)

ENCRYPTION: SOMETYPESOFENCRYPTION (ANDDECRYPTION) AREPERFORMEDATTHEPRESENTATIONLAYER. THISENSURESTHESECURITYOFTHEDATAASITTRAVELSDOWNTHEPROTOCOLSTACK. FOREXAMPLE, ONEOFTHEMOSTPOPULARENCRYPTIONSCHEMESTHATISUSUALLYASSOCIATEDWITHTHEPRESENTATIONLAYERISTHE SECURE SOCKETS LAYER (SSL) PROTOCOL. NOTALLENCRYPTIONISDONEATLAYER 6, HOWEVER; SOMEENCRYPTIONISOFTENDONEATLOWER

LAYERSINTHEPROTOCOLSTACK, INTECHNOLOGIES SUCHASIPSEC.

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http://en.wikipedia.org/wiki/Presentation_Layerhttp://en.wikipedia.org/wiki/Presentation_Layerhttp://en.wikipedia.org/wiki/Presentation_Layerhttp://en.wikipedia.org/wiki/Presentation_Layerhttp://en.wikipedia.org/wiki/Presentation_Layerhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_IPSecurityIPSecProtocols.htmhttp://www.tcpipguide.com/free/t_IPSecurityIPSecProtocols.htmhttp://www.tcpipguide.com/free/t_IPSecurityIPSecProtocols.htmhttp://en.wikipedia.org/wiki/Presentation_Layerhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_PresentationLayerLayer6.htmhttp://www.tcpipguide.com/free/t_IPSecurityIPSecProtocols.htm


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PROTOCOLS :

MIME = MULTIPURPOSE INTERNET MAIL EXTENSIONS

XDR = EXTERNALDATAREPRESENTATION

TLS= TRANSPORTLAYERSECURITY

SSL= SECURESOCKETLAYER

6.3 SESSION LAYER

THEPRIMARYJOBOFSESSIONLAYERPROTOCOLSISTOPROVIDETHEMEANSNECESSARYTOSETUP, MANAGE, ANDENDSESSIONS. SESSIONLAYERTECHNOLOGIESAREOFTENIMPLEMENTEDASSETSOFSOFTWARETOOLSCALLEDAPPLICATIONPROGRAMINTERFACES(APIS), WHICHPROVIDEACONSISTENTSETOFSERVICESTHATALLOWPROGRAMMERS TODEVELOPNETWORKINGAPPLICATIONSWITHOUTNEEDINGTOWORRYABOUTLOWER-LEVEL

DETAILSOFTRANSPORT, ADDRESSINGANDDELIVERY.

PROTOCOLS:NAMED PIPES

NETBIOS SAP= SESSIONANNOUNCEMENTPROTOCOL

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http://en.wikipedia.org/wiki/MIMEhttp://en.wikipedia.org/wiki/External_Data_Representationhttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Secure_Sockets_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://www.tcpipguide.com/free/t_SessionLayerLayer5-2.htmhttp://www.tcpipguide.com/free/t_SessionLayerLayer5-2.htmhttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/NetBIOShttp://en.wikipedia.org/wiki/NetBIOShttp://en.wikipedia.org/wiki/NetBIOShttp://en.wikipedia.org/wiki/Session_Announcement_Protocolhttp://en.wikipedia.org/wiki/MIMEhttp://en.wikipedia.org/wiki/External_Data_Representationhttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Secure_Sockets_Layerhttp://en.wikipedia.org/wiki/Session_Layerhttp://www.tcpipguide.com/free/t_SessionLayerLayer5-2.htmhttp://en.wikipedia.org/wiki/Named_Pipeshttp://en.wikipedia.org/wiki/NetBIOShttp://en.wikipedia.org/wiki/Session_Announcement_Protocol


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6.4 TRANSPORT LAYER

THETRANSPORTLAYERISSAIDTOBERESPONSIBLEFOREND-TO-ENDORHOST-TO-HOSTTRANSPORT

ANOTHERKEYFUNCTIONOFTHETRANSPORTLAYERISTOPROVIDECONNECTIONSERVICESFORTHEPROTOCOLSANDAPPLICATIONSTHATRUNATTHELEVELSABOVEIT. THESECANBECATEGORIZEDASEITHERCONNECTION-ORIENTEDSERVICESORCONNECTIONLESSSERVICES.

THETRANSPORTLAYERISALSOTHEPLACEINTHELAYERSTACKWHEREFUNCTIONSARENORMALLYINCLUDEDTOADDFEATURESTOEND-TO-ENDDATATRANSPORT

PROCESS

-LEVEL

ADDRESSING

: ADDRESSING

AT

LAYER

TWO

DEALS

WITH

HARDWAREDEVICESONALOCALNETWORK, ANDLAYERTHREEADDRESSINGIDENTIFIESDEVICESONALOGICALINTERNETWORK. ADDRESSINGISALSOPERFORMEDATTHETRANSPORTLAYER, WHEREITISUSEDTODIFFERENTIATEBETWEENSOFTWAREPROGRAMS. THISISPARTOFWHATENABLESMANYDIFFERENTSOFTWAREPROGRAMSTOUSEANETWORKLAYERPROTOCOLSIMULTANEOUSLY, ASMENTIONEDABOVE. THEBESTEXAMPLEOFTRANSPORT-LAYERPROCESS-LEVELADDRESSINGISTHETCP AND UDP PORTMECHANISM USEDIN TCP/IP, WHICHALLOWSAPPLICATIONSTOBEINDIVIDUALLYREFERENCEDONANY TCP/IP DEVICE.

MULTIPLEXINGAND DEMULTIPLEXING: USINGTHEADDRESSES I JUSTMENTIONED,

TRANSPORTLAYERPROTOCOLSONASENDINGDEVICEMULTIPLEXTHEDATARECEIVEDFROMMANYAPPLICATION PROGRAMSFORTRANSPORT, COMBININGTHEMINTOASINGLESTREAMOFDATATOBESENT. THESAMEPROTOCOLSRECEIVEDATAANDTHENDEMULTIPLEXITFROMTHEINCOMINGSTREAMOFDATAGRAMS,ANDDIRECTEACHPACKAGEOFDATATOTHEAPPROPRIATERECIPIENTAPPLICATIONPROCESSES.

SEGMENTATION, PACKAGINGAND REASSEMBLY: THETRANSPORTLAYERSEGMENTSTHELARGEAMOUNTSOFDATAITSENDSOVERTHENETWORKINTOSMALLERPIECESONTHESOURCEMACHINE, ANDTHENREASSEMBLETHEMONTHEDESTINATIONMACHINE. THISFUNCTIONISSIMILARCONCEPTUALLYTOTHEFRAGMENTATION

FUNCTIONOFTHENETWORKLAYER; JUSTASTHENETWORKLAYERFRAGMENTSMESSAGESTOFITTHELIMITSOFTHEDATALINKLAYER, THETRANSPORTLAYERSEGMENTSMESSAGESTOSUITTHEREQUIREMENTSOFTHEUNDERLYINGNETWORKLAYER.

CONNECTION ESTABLISHMENT, MANAGEMENTAND TERMINATION: TRANSPORTLAYERCONNECTION-ORIENTEDPROTOCOLSARERESPONSIBLEFORTHESERIESOFCOMMUNICATIONSREQUIREDTOESTABLISHACONNECTION, MAINTAINITASDATAISSENTOVERIT, ANDTHENTERMINATETHECONNECTIONWHENITISNOLONGERREQUIRED.

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http://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htmhttp://en.wikipedia.org/wiki/Transport_Layerhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_ConnectionOrientedandConnectionlessProtocols.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htmhttp://www.tcpipguide.com/free/t_TCPIPTransportLayerProtocolTCPandUDPAddressingPort.htmhttp://www.tcpipguide.com/free/t_TransportLayerLayer4-2.htm


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ACKNOWLEDGMENTSAND RETRANSMISSIONS: ASMENTIONEDABOVE, THETRANSPORTLAYERISWHEREMANYPROTOCOLSAREIMPLEMENTEDTHATGUARANTEERELIABLEDELIVERYOFDATA. THISISDONEUSINGAVARIETYOFTECHNIQUES, MOSTCOMMONLYTHECOMBINATIONOFACKNOWLEDGMENTSAND

RETRANSMISSIONTIMERS. EACHTIMEDATAISSENTATIMERISSTARTED; IFITISRECEIVED, THERECIPIENTSENDSBACKANACKNOWLEDGMENTTOTHETRANSMITTERTOINDICATESUCCESSFULTRANSMISSION. IFNOACKNOWLEDGMENTCOMESBACKBEFORETHETIMEREXPIRES, THEDATAISRETRANSMITTED. OTHERALGORITHMSANDTECHNIQUESAREUSUALLYREQUIREDTOSUPPORTTHISBASICPROCESS.

FLOW CONTROL: TRANSPORTLAYERPROTOCOLSTHATOFFERRELIABLEDELIVERYALSOOFTENIMPLEMENTFLOWCONTROLFEATURES. THESEFEATURESALLOWONEDEVICEINACOMMUNICATIONTOSPECIFYTOANOTHERTHATITMUST "THROTTLEBACK" THERATEATWHICHITISSENDINGDATA, TOAVOIDBOGGINGDOWNTHERECEIVERWITHDATA. THESEALLOWMISMATCHESINSPEEDBETWEENSENDERANDRECEIVERTOBEDETECTEDANDDEALTWITH.

THETWOMOSTIMPORTANTPROTOCOLSOFTRANSPORTARE : TCP & UDP

TCP (TRANSMISSIONCONTROLPROTOCOL) :TCP (TRANSMISSION CONTROL PROTOCOL) ISTHEMOSTCOMMONLYUSEDPROTOCOLON

THE INTERNET. THE REASONFORTHISISBECAUSE TCP OFFERSERROR

CORRECTION. WHENTHE TCP PROTOCOLISUSEDTHEREISA "GUARANTEEDDELIVERY."

THISISDUELARGELYINPARTTOAMETHODCALLED "FLOWCONTROL." FLOWCONTROL

DETERMINESWHENDATANEEDSTOBERE-SENT, ANDSTOPSTHEFLOWOFDATAUNTILPREVIOUSPACKETSARESUCCESSFULLYTRANSFERRED. THISWORKSBECAUSEIFAPACKET

OFDATAISSENT, ACOLLISIONMAYOCCUR. WHENTHISHAPPENS, THECLIENTRE-

REQUESTSTHEPACKETFROMTHESERVERUNTILTHEWHOLEPACKETISCOMPLETEANDISIDENTICALTOITSORIGINAL.

UDP (USER DATAGRAM PROTOCOL) :

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UDP (USER DATAGRAM PROTOCOL) ISANTHERCOMMONLYUSEDPROTOCOLON

THE INTERNET. HOWEVER, UDP ISNEVERUSEDTOSENDIMPORTANTDATASUCHAS

WEBPAGES, DATABASEINFORMATION, ETC; UDP ISCOMMONLYUSEDFORSTREAMING

AUDIOANDVIDEO. STREAMINGMEDIASUCHAS WINDOWS MEDIAAUDIOFILES

(.WMA) , REAL PLAYER (.RM), ANDOTHERSUSE UDP BECAUSEITOFFERSSPEED!

THEREASON UDP ISFASTERTHAN TCP ISBECAUSETHEREISNOFORMOFFLOW

CONTROLORERRORCORRECTION. THEDATASENTOVERTHE INTERNETISAFFECTEDBY

COLLISIONS, ANDERRORSWILLBEPRESENT. REMEMBERTHAT UDP ISONLYCONCERNED

WITHSPEED. THISISTHEMAINREASONWHYSTREAMINGMEDIAISNOTHIGHQUALITY.

FRAME STRUCTURE

ASDATAMOVESALONGANETWORK, VARIOUSATTRIBUTESAREADDEDTOTHE

FILETOCREATEAFRAME.

THEFRAMESTRUCTUREOFTHESEPACKETSDIFFER

THEIMAGESBELOWSHOWBOTHTHE TCP AND UDP FRAMESTRUCTURES.

TCP FRAME STRUCTURE

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UDP FRAME STRUCTURE

THEPAYLOADFIELDCONTAINSTHEACTUALLYDATA.

TCP HASAMORECOMPLEXFRAMESTRUCTURE. THISISLARGELYDUETOTHE

FACTTHE TCP ISACONNECTION-ORIENTEDPROTOCOL.

THEEXTRAFIELDSARENEEDTOENSURETHE "GUARANTEEDDELIVERY" OFFERED

BY TCP.

6.5 NETWORK LAYER

28 | P a g e
http://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layerhttp://en.wikipedia.org/wiki/Transport_Layer


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THENETWORKLAYERISCONCERNEDWITHCONTROLLINGTHEOPERATIONOFTHE SUBNET. A ROUTER ISUSEDTODETERMININGHOWPACKETSAREROUTEDFROM

SOURCETODESTINATION.IFONEPATHISBUSY, THENTHEROUTERWILLSELECTANOTHERPATHFORTHEPACKETSTOTRAVEL. SOREALLY, THEPACKETSCANALLHAVEDIFFERENTPATHSANDFINDTHEIRWAYTOTHEFINALDESTINATION.

NETWORKLAYER FUNCTIONS

SOMEOFTHESPECIFICJOBSNORMALLYPERFORMEDBYTHENETWORKLAYERINCLUDE:

LOGICAL ADDRESSING: EVERYDEVICETHATCOMMUNICATESOVERANETWORKHASASSOCIATEDWITHITALOGICALADDRESS, SOMETIMESCALLEDALAYERTHREEADDRESS. FOREXAMPLE, ONTHEINTERNET, THE INTERNET PROTOCOL (IP) ISTHENETWORKLAYERPROTOCOLANDEVERYMACHINEHASAN IP ADDRESS. NOTETHATADDRESSINGISDONEATTHEDATALINKLAYERASWELL, BUTTHOSEADDRESSESREFERTOLOCALPHYSICALDEVICES. INCONTRAST, LOGICALADDRESSESAREINDEPENDENTOFPARTICULARHARDWAREANDMUSTBEUNIQUEACROSSANENTIREINTERNETWORK.

ROUTING: MOVINGDATAACROSSASERIESOFINTERCONNECTEDNETWORKSISPROBABLYTHEDEFININGFUNCTIONOFTHENETWORKLAYER. ITISTHEJOBOFTHEDEVICESANDSOFTWAREROUTINESTHATFUNCTIONATTHENETWORKLAYERTOHANDLEINCOMINGPACKETSFROMVARIOUSSOURCES, DETERMINETHEIRFINALDESTINATION, ANDTHENFIGUREOUTWHERETHEYNEEDTOBESENTTOGETTHEMWHERETHEYARESUPPOSEDTOGO. I DISCUSSROUTINGINTHE OSI MODELMORECOMPLETELYINTHISTOPICONTHETOPICONINDIRECTDEVICECONNECTION, ANDSHOWHOWITWORKSBYWAYOFANOSI MODELANALOGY.

DATAGRAM ENCAPSULATION: THENETWORKLAYERNORMALLYENCAPSULATESMESSAGESRECEIVEDFROMHIGHERLAYERSBYPLACINGTHEMINTODATAGRAMS(ALSOCALLEDPACKETS) WITHANETWORKLAYERHEADER.

FRAGMENTATION

AND

REASSEMBLY

: THE

NETWORK

LAYER

MUST

SEND

MESSAGES

DOWNTOTHEDATALINKLAYERFORTRANSMISSION. SOMEDATALINKLAYER

TECHNOLOGIES

HAVELIMITSONTHELENGTHOFANYMESSAGETHATCANBESENT. IFTHEPACKET

THATTHENETWORKLAYERWANTSTOSENDISTOOLARGE, THENETWORKLAYER

MUSTSPLITTHEPACKETUP, SENDEACHPIECETOTHEDATALINKLAYER, AND

THENHAVEPIECESREASSEMBLEDONCETHEYARRIVEATTHENETWORKLAYERON

THEDESTINATIONMACHINE. A GOODEXAMPLEISHOWTHISISDONEBYTHE

INTERNET PROTOCOL.

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http://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_DataEncapsulationProtocolDataUnitsPDUsandServiceDa.htmhttp://www.tcpipguide.com/free/t_DataEncapsulationProtocolDataUnitsPDUsandServiceDa.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_IndirectDeviceConnectionandMessageRouting.htmhttp://www.tcpipguide.com/free/t_UnderstandingTheOSIReferenceModelAnAnalogy.htmhttp://www.tcpipguide.com/free/t_DataEncapsulationProtocolDataUnitsPDUsandServiceDa.htmhttp://www.tcpipguide.com/free/t_NetworkLayerLayer3.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htmhttp://www.tcpipguide.com/free/t_IPDatagramSizeMaximumTransmissionUnitMTUFragmentat.htm


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ERROR HANDLINGAND DIAGNOSTICS: SPECIALPROTOCOLSAREUSEDATTHENETWORKLAYERTOALLOWDEVICESTHATARELOGICALLYCONNECTED, ORTHATARETRYINGTOROUTETRAFFIC, TOEXCHANGEINFORMATIONABOUTTHESTATUSOFHOSTSONTHENETWORKORTHEDEVICESTHEMSELVES.

THETWOMOSTIMPORTANTPROTOCOLSOFNETWORKLAYERARE: I.P AND ICPM

6.5.1 IP INTERNETPROTOCOL:

INTERNETPROTOCOLISASSOCIATEDWITHI.PADDRESSWHICHISUNIQUETOEVERYDEVICE

ONTHEINTERNET /ORWECANSAYIPADDRESSISUNIQUE :

I.PVERSIONS:

TWOVERSIONSOF IP TECHNOLOGYEXISTTODAY. ESSENTIALLYALLHOMECOMPUTER

NETWORKSUSE IP VERSION 4 (IPV4), BUTANINCREASINGNUMBEROFEDUCATIONAL

ANDRESEARCHINSTITUTIONSHAVEADOPTEDTHENEXTGENERATION IP VERSION 6

(IPV6).

IPV4 ADDRESSING NOTATION

AN IPV4 ADDRESSCONSISTSOFFOURBYTES (32 BITS). THESEBYTESAREALSOKNOWN

ASOCTETS.

FORREADABILITYPURPOSES, HUMANSTYPICALLYWORKWITH IP ADDRESSESINA

NOTATIONCALLEDDOTTEDDECIMAL. THISNOTATIONPLACESPERIODSBETWEENEACHOF

THEFOURNUMBERS (OCTETS) THATCOMPRISEAN IP ADDRESS. FOREXAMPLE, AN IP

ADDRESSTHATCOMPUTERSSEEAS

00001010 00000000 00000000 00000001

ISWRITTENINDOTTEDDECIMALAS

10.0.0.1

BECAUSEEACHBYTECONTAINS 8 BITS, EACHOCTETINAN IP ADDRESSRANGESINVALUE

FROMAMINIMUMOF 0 TOAMAXIMUMOF 255. THEREFORE, THEFULLRANGEOF IP

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ADDRESSESISFROM 0.0.0.0 THROUGH 255.255.255.255. THATREPRESENTSA

TOTALOF 4,294,967,296 POSSIBLE IP ADDRESES.

IP ADDRESSESCHANGESIGNIFICANTLYWITH IPV6. IPV6 ADDRESSESARE 16 BYTES

(128 BITS) LONGRATHERTHANFOURBYTES (32 BITS). THISLARGERSIZEMEANSTHATIPV6 SUPPORTSMORETHAN

300,000,000,000,000,000,000,000,000,000,000,000,000

POSSIBLEADDRESSES! INTHECOMINGYEARS

EXAMPLE:

E3D7:0000:0000:0000:51F4:9BC8:C0A8:6420

PARTSOFAN IP ADDRESS

THEEXAMPLEBELOWSHOWSTHECOMPONENTSOFTHE CLASS B NETWORK

192.168.1.100.

192.168.1.100------- -----

| |___ (HOSTPART)||____ (NETWORKPART)

NETWORK PARTTHISPARTSPECIFIESTHEUNIQUENUMBERASSIGNEDTOYOURPARTICULARNETWORK. ITITALSOTHEPARTTHATIDENTIFIESTHECLASSOFNETWORKASSIGNED. INTHEABOVEEXAMPLE, THENETWORKPARTTAKESUPTWOBYTESOFTHE IP ADDRESS, NAMELY192.168.

HOST PARTTHISISTHEPARTOFTHE IP ADDRESSTHATYOUASSIGNTOEACHHOST, ANDUNIQUELYIDENTIFIESEACHHOSTONYOURNETWORK. NOTETHATFOREACHHOSTONYOURNETWORK, THENETWORKPARTOFTHEADDRESSWILLBETHESAME, BUTTHEHOSTPARTMUSTBEDIFFERENT

NETWORK CLASSES

CURRENTLY, THEREARETHREECLASSESOF TCP/IP NETWORKS. EACHCLASSUSESTHE32-BIT IP ADDRESSSPACEDIFFERENTLY, PROVIDINGMOREORFEWERBITSFORTHENETWORKPARTOFTHEADDRESS. THESECLASSESARE CLASS A, B AND CLASS C.

CLASS A NETWORKNUMBERSA CLASS A NETWORKNUMBERUSESTHEFIRST 8 BITSOFTHE IP ADDRESSASITS "NETWORKPART". THEREMAINING 24 BITSCOMPRISETHEHOSTPARTOFTHE

IP ADDRESS. (SEEBELOW)

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BITS 0 7-8 15-16 23-24 31+------------+------------+------------+------------+| NETWORK | HOST || PART | PART |

+------------+------------+------------+------------+THEVALUESAREASSIGNEDTOTHEFIRSTBYTEOF CLASS A NETWORKNUMBERSFALLWITHINTHERANGE 0-127. CONSIDERFOREXAMPLETHE IP ADDRESS68.8.1.100. THEVALUE 68 INTHEFIRSTBYTEINDICATESTHATTHEHOSTISONA CLASS A NETWORK. THE INTER NIC ASSIGNSONLYTHEFIRSTBYTEOFACLASS A NUMBER. USEOFTHEREMAININGTHREEBYTESISLEFTTOTHEDISCRETIONOFTHEOWNEROFNETWORKNUMBER. ONLY 127 CLASS ANETWORKSCANEXIST. EACHONEOFTHESENUMBERSCANACCOMMODATEUPTO16,777,214 HOSTS.

CLASS B NETWORKNUMBERS

A CLASS B NETWORKNUMBERCONSISTSOFTHEFIRST 16 BITSFORTHENETWORKNUMBERAND 16 BITSFORHOSTNUMBERS. THEFIRSTBYTEOFACLASS B NETWORKNUMBERISINTHERANGE 128-191. TAKEFOREXAMPLETHE IP ADDRESS 132.168.1.100, THEFIRSTTWOBYTES, 132.168, AREASSIGNEDBYTHE INTERNIC, ANDCOMPRISETHENETWORKADDRESS. THELASTTWOBYTES, 1.100, MAKEUPTHEHOSTPARTOFTHEADDRESS, ANDISASSIGNEDATTHEDISCRETIONOFTHEOWNEROFTHENETWORKNUMBER. (SEEBELOW)BITS 0 7-8 15-16 23-24 31

+------------+------------+------------+------------+| NETWORK | HOST |

| PART | PART |+------------+------------+------------+------------+

CLASS B ISTYPICALLYASSIGNEDTOORGANIZATIONSWITHMANYHOSTSONTHEIRNETWORK.

CLASS C NETWORKNUMBERSA CLASS C NETWORKUSES 24 BITSFORTHENETWORKPARTAND 8 BITSFORTHEHOSTPART. CLASS C NETWORKNUMBERSAREAPPROPRIATEFORNETWORKSWITHFEWHOSTS - THEMAXIMUMBEING 254. A CLASS C NETWORKNUMBEROCCUPIESTHEFIRSTTHREEBYTESOFAN IP ADDRESS. ONLYTHEFOURTHBYTEISASSIGNEDATTHEDISCRETIONOFTHENETWORKNUMBEROWNER. (SEEBELOW)

BITS 0 7-8 15-16 23-24 31+------------+------------+------------+------------+| NETWORK | HOST || PART | PART |+------------+------------+------------+------------+

THEFIRSTBYTESOFACLASS C NETWORKNUMBERCOVERSTHERANGE 192-223. THESECONDANDTHIRDEACHCOVERTHERANGE 1-255. A TYPICALCLASS C ADDRESSMIGHTBE 192.98.1.100. THEFIRSTTHREEBYTES,192.98.1, FORMTHENETWORKNUMBER. THEFINALBYTEINTHISEXAMPLE,100, ISTHEHOSTNUMBER

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PUBLICAND PRIVATE IP ADDRESSES

A PUBLIC IP ADDRESSMAKESYOUREQUIPMENTACCESSIBLETOEVERYONEONTHE

INTERNETANDISNEEDEDFOR VOIP ORIFYOUWANTTOGIVEOTHERSTOACCESS

TOSPECIFICEQUIPMENTONYOURNETWORK.

A PRIVATE IP ADDRESSISFORPRIVATEUSEWITHINTHENETWORKANDALLOWS

MANYMORE PCSTOBECONNECTED. IFACUSTOMERISUSINGAPRIVATE IP AND

LATERWANTS VOIP THEYWOULDNEEDTOCHANGETOAPUBLIC IP ADDRESS.

DHCP

DYNAMIC HOST CONFIGURATION PROTOCOL (DHCP) ISANETWORKPROTOCOLTHATENABLESASERVERTOAUTOMATICALLYASSIGNAN IP ADDRESSTOACOMPUTERFROMADEFINEDRANGEOFNUMBERS (I.E., ASCOPE) CONFIGUREDFORAGIVENNETWORK.

NATDEVELOPEDBY CISCO, NETWORKADDRESS TRANSLATIONISUSEDBYADEVICE(FIREWALL, ROUTER ORCOMPUTER) THATSITSBETWEENANINTERNALNETWORKANDTHERESTOFTHEWORLD. BASICALLYITCONVERTSPRIVATE IP TOPUBLICANDVICEVERSANAT HASMANYFORMSANDCANWORKINSEVERALWAYS:

STATIC NAT - MAPPINGANUNREGISTERED IP ADDRESSTOAREGISTERED IPADDRESSONAONE-TO-ONEBASIS. PARTICULARLYUSEFULWHENADEVICENEEDSTOBEACCESSIBLEFROMOUTSIDETHENETWORK.

DYNAMIC NAT - MAPSANUNREGISTERED IP ADDRESSTOAREGISTERED IPADDRESSFROMAGROUPOFREGISTERED IP ADDRESSES.

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6.6 DATA LINK LAYER

THESECOND-LOWESTLAYER (LAYER 2) INTHE OSI REFERENCE MODELSTACKISTHEDATALINKLAYER.MANYWIREDANDWIRELESSLOCALAREANETWORKING (LAN) TECHNOLOGIESPRIMARILYFUNCTIONINTHISLAYER. FOREXAMPLE, ETHERNET, TOKEN RING, FDDI AND 802.11

DATA LINK LAYER SUBLAYERS: LOGICAL LINK CONTROL (LLC) AND MEDIA ACCESSCONTROL (MAC)

LLC

THISSUBLAYERMULTIPLEXESPROTOCOLSRUNNINGATOPTHE DATA LINK LAYER,ANDOPTIONALLYPROVIDESFLOWCONTROL, ACKNOWLEDGMENT, ANDERRORNOTIFICATION.

PROVIDESADDRESSINGANDCONTROLOFTHEDATALINK

MAC

ITPROVIDESADDRESSINGANDCHANNELACCESSCONTROLMECHANISMS

THE MAC LAYERADDRESSINGMECHANISMISCALLEDPHYSICALADDRESSOR

MAC ADDRESS.

A MAC ADDRESSISAUNIQUESERIALNUMBERASSIGNEDTOAPARTICULARPIECE

OFNETWORKHARDWARE

EACHDEVICEINANETWORKWILLHAVEADIFFERENT MAC ADDRESS

THISMAKESITPOSSIBLEFORDATAPACKETSTOBEDELIVEREDTOADESTINATION

WITHINASUBNETWORK.

CHANNELACCESSCONTROLMECHANISMSPROVIDEDBYTHE MAC LAYERARE

KNOWNASAMULTIPLEACCESSPROTOCOL.

DATA LINK LAYER FUNCTIONS

THEFOLLOWINGARETHEKEYTASKSPERFORMEDATTHEDATALINKLAYER:

LOGICAL LINK CONTROL (LLC): LOGICALLINKCONTROLREFERSTOTHEFUNCTIONSREQUIREDFORTHEESTABLISHMENTANDCONTROLOFLOGICALLINKSBETWEENLOCALDEVICESONANETWORK. ASMENTIONEDABOVE, THISISUSUALLYCONSIDEREDA DLL SUBLAYER; ITPROVIDESSERVICESTOTHENETWORKLAYERABOVEITANDHIDESTHERESTOFTHEDETAILSOFTHEDATALINKLAYERTOALLOWDIFFERENTTECHNOLOGIESTOWORKSEAMLESSLYWITHTHEHIGHERLAYERS.MOSTLOCALAREANETWORKINGTECHNOLOGIESUSETHE IEEE 802.2 LLCPROTOCOL.

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MEDIA ACCESS CONTROL (MAC): THISREFERSTOTHEPROCEDURESUSEDBYDEVICESTOCONTROLACCESSTOTHENETWORKMEDIUM. S INCEMANYNETWORKSUSEASHAREDMEDIUM (SUCHASASINGLENETWORKCABLE, ORASERIESOFCABLESTHATAREELECTRICALLYCONNECTEDINTOASINGLEVIRTUALMEDIUM) ITIS

NECESSARYTOHAVERULESFORMANAGINGTHEMEDIUMTOAVOIDCONFLICTS.FOREXAMPLE. ETHERNETUSESTHE CSMA/CD METHODOFMEDIAACCESSCONTROL, WHILE TOKEN RINGUSESTOKENPASSING.

DATA FRAMING: THEDATALINKLAYERISRESPONSIBLEFORTHEFINALENCAPSULATIONOFHIGHER-LEVELMESSAGESINTOFRAMESTHATARESENTOVERTHENETWORKATTHEPHYSICALLAYER.

ADDRESSING: THEDATALINKLAYERISTHELOWESTLAYERINTHE OSI MODELTHATISCONCERNEDWITHADDRESSING: LABELINGINFORMATIONWITHAPARTICULARDESTINATIONLOCATION. EACHDEVICEONANETWORKHASAUNIQUENUMBER, USUALLYCALLEDAHARDWAREADDRESSOR MAC ADDRESS, THATISUSEDBYTHEDATALINKLAYERPROTOCOLTOENSURETHATDATAINTENDEDFORASPECIFICMACHINEGETSTOITPROPERLY.

ERROR DETECTIONAND HANDLING: THEDATALINKLAYERHANDLESERRORSTHATOCCURATTHELOWERLEVELSOFTHENETWORKSTACK. FOREXAMPLE, ACYCLICREDUNDANCYCHECK(CRC) FIELDISOFTENEMPLOYEDTOALLOWTHESTATIONRECEIVINGDATATODETECTIFITWASRECEIVEDCORRECTLY.

6.7 PHYSICAL LAYERTHELOWESTLAYEROFTHE OSI REFERENCE MODE , ITISWHEREDATAISPHYSICALLYMOVEDACROSSTHENETWORK.

THEFOLLOWINGARETHEMAINRESPONSIBILITIESOFTHEPHYSICALLAYERINTHE OSIREFERENCE MODEL:

DEFINITIONOF HARDWARE SPECIFICATIONS: THEDETAILSOFOPERATIONOFCABLES, CONNECTORS, WIRELESSRADIOTRANSCEIVERS, NETWORKINTERFACECARDSANDOTHERHARDWAREDEVICESAREGENERALLYAFUNCTIONOFTHE

PHYSICALLAYER (ALTHOUGHALSOPARTIALLYTHEDATALINKLAYER; SEEBELOW).

ENCODINGAND SIGNALING: THEPHYSICALLAYERISRESPONSIBLEFORVARIOUSENCODINGANDSIGNALINGFUNCTIONSTHATTRANSFORMTHEDATAFROMBITSTHATRESIDEWITHINACOMPUTER OROTHERDEVICEINTOSIGNALSTHATCANBESENTOVERTHENETWORK.

DATA TRANSMISSIONAND RECEPTION: AFTERENCODINGTHEDATAAPPROPRIATELY, THEPHYSICALLAYERACTUALLYTRANSMITSTHEDATA, ANDOFCOURSE, RECEIVESIT. NOTETHATTHISAPPLIESEQUALLYTOWIREDANDWIRELESSNETWORKS, EVENIFTHEREISNOTANGIBLECABLEINAWIRELESSNETWORK.

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TOPOLOGYAND PHYSICAL NETWORKDESIGN: THEPHYSICALLAYERISALSOCONSIDEREDTHEDOMAIN OFMANYHARDWARE-RELATEDNETWORKDESIGNISSUES,SUCHASLAN AND WAN TOPOLOGY.

CABLES

CABLEISTHEMEDIUMTHROUGHWHICHINFORMATIONUSUALLYMOVESFROMONENETWORKDEVICETOANOTHER

THEFOLLOWINGSECTIONSDISCUSSTHETYPESOFCABLESUSEDINNETWORKSANDOTHERRELATEDTOPICS.

UNSHIELDED TWISTED PAIR (UTP) CABLE SHIELDED TWISTED PAIR (STP) CABLE COAXIAL CABLE FIBER OPTIC CABLE CABLE INSTALLATION GUIDES WIRELESS LANS

Unshielded Twisted Pair (UTP) Cable

THECABLEHASFOURPAIRSOFWIRESINSIDETHEJACKET. EACHPAIRISTWISTEDWITHADIFFERENTNUMBEROFTWISTSPERINCHTOHELPELIMINATEINTERFERENCEFROMADJACENTPAIRSANDOTHERELECTRICALDEVICES. THETIGHTERTHETWISTING, THEHIGHERTHESUPPORTED

TRANSMISSIONRATEANDTHEGREATERTHECOSTPERFOOT. THEEIA/TIA (ELECTRONIC INDUSTRY ASSOCIATION/TELECOMMUNICATIONINDUSTRY ASSOCIATION) HASESTABLISHEDSTANDARDSOF UTP ANDRATEDSIXCATEGORIESOFWIRE (ADDITIONALCATEGORIESAREEMERGING).

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CATEGORIESOF UNSHIELDED TWISTED PAIR

Category Speed Use

1. 1 Mbps Voice Only (Telephone

Wire)

2. 4 Mbps LocalTalk & Telephone(Rarely used)

3. 16 Mbps 10BaseT Ethernet

4. 20 Mbps Token Ring (Rarely

used)

5. 100 Mbps (2 pair)

1000 Mbps (4

pair)

100BaseT Ethernet

Gigabit Ethernet

5e. 1,000 Mbps Gigabit Ethernet

6. 10,000 Mbps Gigabit Ethernet

THESTANDARDCONNECTORFORUNSHIELDEDTWISTEDPAIRCABLINGISAN RJ-45

CONNECTOR

SHIELDED TWISTED PAIR (STP) CABLE

UTP CABLE ARE SUSCEPTIBLETORADIOANDELECTRICALFREQUENCY

INTERFERENCE

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SHIELDEDTWISTEDPAIR IS THE SOLUTION

SHIELDEDCABLESCANALSOHELPTOEXTENDTHEMAXIMUMDISTANCEOFTHE

CABLES

SHIELDEDTWISTEDPAIRCABLEISAVAILABLEINTHREEDIFFERENTCONFIGURATIONS:

1. EACHPAIROFWIRESISINDIVIDUALLYSHIELDEDWITHFOIL.2. THEREISAFOILORBRAIDSHIELDINSIDETHEJACKETCOVERINGALLWIRES (ASAGROUP).3. THEREISASHIELDAROUNDEACHINDIVIDUALPAIR, ASWELLASAROUNDTHEENTIREGROUPOFWIRES (REFERREDTOASDOUBLESHIELDTWISTEDPAIR).

COAXIAL CABLE COAXIALCABLINGHASASINGLECOPPERCONDUCTORATITSCENTER

A PLASTICLAYERPROVIDESINSULATIONBETWEENTHECENTERCONDUCTOR

ANDABRAIDEDMETALSHIELD

THEMETALSHIELDHELPSTOBLOCKANYOUTSIDEINTERFERENCEFROM

CONNECTORUSEDWITHCOAXIALCABLESISTHE BAYONE-NEILL-CONCELMAN

(BNC) CONNECTOR

Fig. 4. BNC connector

FIBER OPTIC CABLE

IT HAS CENTERGLASSCORESURROUNDEDBYSEVERALLAYERSOFPROTECTIVE

MATERIALS

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ITTRANSMITSLIGHTRATHERTHANELECTRONICSIGNALS

IT CAN TRANSMITSIGNALSOVERMUCHLONGERDISTANCES

THECENTERCOREOFFIBERCABLESISMADEFROMGLASSORPLASTICFIBERS

A PLASTICCOATINGTHENCUSHIONSTHEFIBERCENTER

KEVLARFIBERSHELPTOSTRENGTHENTHECABLESANDPREVENTBREAKAGE

THEOUTERINSULATINGJACKETMADEOFTEFLONOR PVC.

Fig. 5. Fiber optic cab

Ethernet Cable Summary

Specifica

tion

Cable Type

10BaseT Unshielded Twisted Pair

10Base2 Thin Coaxial

10Base5 Thick Coaxial

100Base

T

Unshielded Twisted Pair

100Base

FX

Fiber Optic

100BaseBX

Single mode Fiber

100BaseS

X

Multimode Fiber

1000Base

T

Unshielded Twisted Pair

1000Base

FX

Fiber Optic

1000Base Single mode Fiber

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BX

1000Base

SX

Multimode Fiber

WIRELESS LANS

WIRELESS LANSUSEHIGHFREQUENCYRADIOSIGNALS, INFRAREDLIGHTBEAMS, OR

LASERSTOCOMMUNICATEBETWEENTHEWORKSTATIONSANDTHEFILESERVERORHUBS

WIFI (WIRELESS FIDELITY). NETWORKSUSETHE ETHERNETPROTOCOL.

Standard Max Speed Typical Range

802.11a 54 Mbps 150 feet

802.11b 11 Mbps 300 feet

802.11g 54 bps 300

et

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6.HOW COMMUNICATIONOCCURS O.S.I VIEW

6.1 BETWEEN TWO COMPUTERS:

HERE'SWHATHAPPENS:

A HIGH-LEVELAPPLICATIONON MACHINE 1 DECIDESTOSENDADATAGRAMTOCOMPUTER 2 . THEDATAGRAMISPACKAGED, ANDTHENPASSEDDOWNVERTICALLYTHROUGHTHEPROTOCOLSTACKONTHEORIGINATINGMACHINE. EACHLAYERENCAPSULATESTHEDATAASDESCRIBEDEARLIER. THEDATAGRAMISADDRESSEDTOTHEFINALDESTINATIONDEVICE (IE, THE I.PWEASSIGN). WHENTHEMESSAGEGETSTOTHENETWORKLAYERANDBELOW, HOWEVER, ITIS PACKAGEDFORLOCALDELIVERYDIRECTLYTOITSULTIMATEDESTINATION,THEMESSAGEISPASSEDDOWNTOTHEDATALINKLAYERANDTHENTHEPHYSICALLAYERFORTRANSMISSIONTHROUGHETHERNETPORT.

NOWTHEMESSAGETRAVELSTHROUGHTHE LAN CABLEANDISRECEIVEDATATTHEOTHEREND .

MACHINE 2 RECEIVESTHEMESSAGETHROUGHETHERNETPORTATTHEPHYSICALLAYER. ITISPASSEDUPTOTHEDATALINKLAYER, WHEREITISPROCESSED, CHECKEDFORERRORSANDSOON, ANDTHEDATALINKLAYERHEADERSAREREMOVED. THERESULTINGPACKETISPASSEDUPTOTHENETWORKLAYER. THERE, THECOMPUTER 2DETERMINESIFTHEMESSAGEISFORHIM -> YES, THEMESSAGEISFORWARDEDUP /NO-> THEMESSAGEISREJECTED

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6.2 BETWEENTWOCOMPUTERSONALAN

STEP 1 ISSAMEASTHATINCOMMUNICATIONB/WTWO COMPUTERS

THESWITCHDEVICERECEIVESTHEMESSAGEATTHEPHYSICALLAYER. ITISPASSED

UPTOTHEDATALINKLAYER, WHEREITISPROCESSED, CHECKEDFORERRORSAND

SOON, AND MAC ADDRESSOFDESTINATION & SENDERSARECHECKED . THERE,

THEINTERMEDIATEDEVICEDETERMINESIFTHEDESTINATIONMACHINEISONITSLOCAL

NETWORK IFNOTTHEMESSAGEISREJECTED . ITTHENREPACKAGESTHEMESSAGE

ANDPASSESITBACKDOWNTOTHEPHYSICALLAYERTOBESENTONTHEDESTINATIONMACHINE .

THEDESTINATIONMACHINESAGAINPASSES UPMESSAGETOTHEDATALINKLAYER,WHEREITISPROCESSED, CHECKEDFORERRORSANDSOON, ANDTHEDATALINKLAYERHEADERSAREREMOVED. THERESULTINGPACKETISPASSEDUPTOTHENETWORKLAYER. THERE, THECOMPUTER 2 DETERMINESIFTHEMESSAGEISFORHIM-> YES, THEMESSAGEISFORWARDEDUP / NO-> THEMESSAGEISREJECTED.

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6.3 BETWEENWANNETWORKS

A HIGH-LEVELAPPLICATIONON MACHINE 1 DECIDESTOSENDADATAGRAMTOCOMPUTER 2 . THEDATAGRAMISPACKAGED, ANDTHENPASSEDDOWNVERTICALLYTHROUGHTHEPROTOCOLSTACKONTHEORIGINATINGMACHINE.EACHLAYERENCAPSULATESTHEDATAASDESCRIBEDEARLIER. THEDATAGRAMISADDRESSEDTOTHEFINALDESTINATIONDEVICE (IE, THE I.PWEASSIGN). WHEN

THEMESSAGEGETSTOTHENETWORKLAYERANDBELOW, HOWEVER, ITISPACKAGEDFORLOCALDELIVERYDIRECTLYTOITSULTIMATEDESTINATION,THEMESSAGEISPASSEDDOWNTOTHEDATALINKLAYERANDTHENTHEPHYSICALLAYERFORTRANSMISSIONTHROUGHETHERNETPORT.

THEINTERMEDIATEDEVICE (OFTENCALLEDAROUTER) RECEIVESTHEMESSAGEATTHEPHYSICALLAYER. ITISPASSEDUPTOTHEDATALINKLAYER, WHEREITISPROCESSED, CHECKEDFORERRORSANDSOON, ANDTHEDATALINKLAYERHEADERSAREREMOVED. THERESULTINGPACKETISPASSEDUPTOTHENETWORKLAYER.

THERE, THEINTERMEDIATEDEVICEDETERMINESIFTHEDESTINATIONMACHINEISON

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ITSLOCALNETWORK, ORIFITNEEDSTOBEFORWARDEDTOANOTHERINTERMEDIATEDEVICE. ITTHENREPACKAGESTHEMESSAGEANDPASSESITBACKDOWNTOTHEDATALINKLAYERTOBESENTONTHENEXTLEGOFITSJOURNEY.

AFTERSEVERALPOTENTIALINTERMEDIATEDEVICES HANDLE THEMESSAGE, ITEVENTUALLYREACHESITSDESTINATION. HERE, ITTRAVELSBACKUPTHEPROTOCOLSTACKUNTILITREACHESTHESAMELAYERASTHEONEOFTHEAPPLICATIONTHATGENERATEDTHEMESSAGEONTHEORIGINATINGMACHINE.

7.THETCP/IPMODEL

TCP/IP ISBASEDONAFOUR-LAYERREFERENCEMODEL.

ALLPROTOCOLSTHATBELONGTOTHE TCP/IP PROTOCOLSUITEARELOCATEDINTHETOPTHREELAYERSOFTHIS

MODEL.ASSHOWNINTHEFOLLOWINGILLUSTRATION, EACH

LAYEROFTHE TCP/IP MODELCORRESPONDSTOONEOR

MORELAYERSOFTHESEVEN-LAYER OPEN SYSTEMS

INTERCONNECTION (OSI) REFERENCEMODELPROPOSEDBY

THE INTERNATIONAL STANDARDS ORGANIZATION (ISO).

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8.NMS

A NETWORKMANAGEMENT SYSTEM (NMS) ISACOMBINATIONOFHARDWAREANDSOFTWAREUSEDTOMONITORANDADMINISTERANETWORK.

THENETWORKMANAGEMENTSYSTEMSHOULDDISCOVERTHENETWORKINVENTORY

MONITORTHEHEALTHANDSTATUSOFDEVICES

PROVIDEALERTSTOCONDITIONSTHATIMPACTSYSTEMPERFORMANCE

NMS SOFTWAREISRESPONSIBLEFORIDENTIFICATIONOFTHEPROBLEM.

SNMP PROTOCOLALLOWSITTOSIMPLYGATHERTHEINFORMATIONFROMTHE

VARIOUSDEVICESDOWNTHENETWORKHIERARCHY

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8.1 SNMP (SIMPLE NETWORKMANAGEMENT

PROTOCOL)

SIMPLE NETWORK MANAGEMENT PROTOCOL (SNMP) ISANAPPLICATIONLAYERPROTOCOLDEFINEDBYTHE INTERNET ARCHITECTURE BOARD (IAB)

IN RFC1157 FOREXCHANGINGMANAGEMENTINFORMATIONBETWEEN

NETWORKDEVICES. ITISAPARTOF TRANSMISSION CONTROL PROTOCOL

INTERNET PROTOCOL (TCPIP) PROTOCOLSUITE.

SNMP ISONEOFTHEWIDELYACCEPTEDPROTOCOLSTOMANAGEANDMONITOR

NETWORKELEMENTS. MOSTOFTHEPROFESSIONALGRADENETWORK

ELEMENTSCOMEWITHBUNDLED SNMP AGENT. THESEAGENTSHAVETO

BEENABLEDANDCONFIGUREDTOCOMMUNICATEWITHTHENETWORK

MANAGEMENTSYSTEM (NMS).

HOWCAN SNMP HELPME?

SNMP CANDOAVARIETYOFTHINGS. HEREARESOMEWAYSITHASHELPEDME:

ITCANGRAPH CISCOROUTER/SWITCHBANDWIDTHUTILIZATIONOVERTIME, PERINTERFACE, PERDIRECTION, ETC.

ITCANGRAPHERRORSONNETWORKDEVICES (E.G., CRC ERRORS). ITCANSENDALERTSWHENANINTERFACEGOESUPORDOWN.

WHATISTHEROLEOF NMS?

YOUNEEDSOMEKINDOF NMS (NETWORKMONITORINGSOFTWARE) TOMAKE SNMPUSEFUL. CONFIGURING SNMP ONITSOWNREALLYWONTTELLYOUANYTHING. YOUNEEDAN NMS THATYOUCANCONFIGURETORECEIVE, REPORT, ANDGRAPHTHE SNMPINFORMATION.

SNMP BASIC COMPONENTS

AN SNMP-MANAGEDNETWORKCONSISTSOFTHREEKEYCOMPONENTS:

SNMP MANAGER MANAGED DEVICE SNMP AGENT MANAGEMENT INFORMATION DATABASEALSOKNOWNAS MANAGEMENT

INFORMATIONBASE

SNMP MANAGER

A MANAGERORMANAGEMENTSYSTEMISASEPARATEENTITYTHATISRESPONSIBLETOCOMMUNICATEWITHTHE SNMP AGENTIMPLEMENTEDNETWORKDEVICES. THISIS

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TYPICALLYACOMPUTERTHATISUSEDTORUNONEORMORENETWORKMANAGEMENTSYSTEMS.

SNMP MANAGERSKEYFUNCTIONS

QUERIESAGENTS GETSRESPONSEFROMAGENTS SETSVARIABLESINAGENTS ACKNOWLEDGESASYNCHRONOUSEVENTSFROMAGENTS

MANAGEDDEVICE

A MANAGEDDEVICEORTHENETWORKELEMENTISAPARTOFTHENETWORKTHAT

REQUIRESSOMEFORMOFMONITORINGANDMANAGEMENTE.G. ROUTERS, SWITCHES,

SERVERS, WORKSTATIONS, PRINTERS, UPSS, ETC...

SNMP AGENT

THEAGENTISAPROGRAMTHATISPACKAGEDWITHINTHENETWORKELEMENT.ENABLINGTHEAGENTALLOWSITTOCOLLECTTHEMANAGEMENTINFORMATIONDATABASEFROMTHEDEVICELOCALLYANDMAKESITAVAILABLETOTHE SNMPMANAGER, WHENITISQUERIEDFOR. THESEAGENTSCOULDBESTANDARD (E.G.NET-SNMP) ORSPECIFICTOAVENDOR (E.G. HP INSIGHTAGENT)

SNMP AGENTSKEYFUNCTIONS

COLLECTSMANAGEMENTINFORMATIONABOUTITSLOCALENVIRONMENT STORESANDRETRIEVESMANAGEMENTINFORMATIONASDEFINEDINTHE MIB. SIGNALSANEVENTTOTHEMANAGER. ACTSASAPROXYFORSOMENONSNMP MANAGEABLENETWORKNODE.

MANAGEMENTINFORMATIONBASE

EVERY SNMP AGENTMAINTAINSANINFORMATIONDATABASEDESCRIBINGTHE

MANAGEDDEVICEPARAMETERS. THE SNMP MANAGERUSESTHISDATABASETOREQUESTTHEAGENTFORSPECIFICINFORMATIONANDFURTHERTRANSLATESTHEINFORMATIONASNEEDEDFORTHE NETWORKMANAGEMENT SYSTEM (NMS).THISCOMMONLYSHAREDDATABASEBETWEENTHE AGENTANDTHE MANAGERISCALLED MANAGEMENT INFORMATION BASE (MIB).

TYPICALLYTHESE MIB CONTAINSSTANDARDSETOFSTATISTICALANDCONTROLVALUESDEFINEDFORHARDWARENODESONANETWORK. SNMP ALSOALLOWSTHEEXTENSIONOFTHESESTANDARDVALUESWITHVALUESSPECIFICTOAPARTICULARAGENTTHROUGHTHEUSEOFPRIVATE MIBS.

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INSHORT, MIB FILESARETHESETOFQUESTIONSTHATA SNMP MANAGERCANASKTHEAGENT. AGENTCOLLECTSTHESEDATALOCALLYANDSTORESIT, ASDEFINEDINTHE MIB. SO, THE SNMP MANAGERSHOULDBEAWAREOFTHESESTANDARDANDPRIVATEQUESTIONSFOREVERYTYPEOFAGENT.

BASIC SNMP COMMANDS

GET: THE GET OPERATIONISAREQUESTSENTBYTHEMANAGERTOTHEMANAGED

DEVICE. ITISPERFORMEDTORETRIEVEONEORMOREVALUESFROMTHEMANAGED

DEVICE.

GET NEXT: THISOPERATIONISSIMILARTOTHE GET. THESIGNIFICANTDIFFERENCE

ISTHATTHE GET NEXT OPERATIONRETRIEVESTHEVALUEOFTHENEXT OID INTHE

MIB TREE.

GET BULK: THE GETBULKOPERATIONISUSEDTORETRIEVEVOLUMINOUSDATA

FROMLARGE MIB TABLE.

SET: THISOPERATIONISUSEDBYTHEMANAGERSTOMODIFYORASSIGNTHEVALUEOF

THE MANAGEDDEVICE.

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TRAPS: UNLIKETHEABOVECOMMANDSWHICHAREINITIATEDFROMTHE SNMP

MANAGER, TRAPS AREINITIATEDBYTHE AGENTS. ITISASIGNALTOTHE SNMP

MANAGERBYTHE AGENTONTHEOCCURRENCEOFANEVENT.

INFORM: THISCOMMANDISSIMILARTOTHE TRAP INITIATEDBYTHE AGENT,ADDITIONALLY INFORM INCLUDESCONFIRMATIONFROMTHE SNMP MANAGERON

RECEIVINGTHEMESSAGE.

RESPONSE: ITISTHECOMMANDUSEDTOCARRYBACKTHEVALUE(S) ORSIGNALOF

ACTIONSDIRECTEDBYTHE SNMP MANAGER.

SNMP VERSIONS

SINCETHEINCEPTION SNMP, HASGONETHROUGHSIGNIFICANTUPGRADES. HOWEVER

SNMP V1 ANDV2CARETHEMOSTIMPLEMENTEDVERSIONSOF SNMP. SUPPORTTO

SNMP V3 HASRECENTLYSTARTEDCATCHINGUPASITISMORESECUREDWHEN

COMPARETOITSOLDERVERSIONS, BUTSTILLITHASNOTREACHEDCONSIDERABLE

MARKETSHARE.

SNMPV1:

THISISTHEFIRSTVERSIONOFTHEPROTOCOL, WHICHISDEFINEDIN RFCS 1155 AND

1157

SNMPV2C:

THISISTHEREVISEDPROTOCOL, WHICHINCLUDESENHANCEMENTSOF SNMPV1 INTHE

AREASOFPROTOCOLPACKETTYPES, TRANSPORTMAPPINGS, MIB STRUCTUREELEMENTS

BUTUSINGTHEEXISTING SNMPV1 ADMINISTRATIONSTRUCTURE ("COMMUNITYBASED"

ANDHENCE SNMPV2C). ITISDEFINEDIN RFC 1901, RFC 1905, RFC 1906,

RFC 2578.

SNMPV3:

SNMPV3 DEFINESTHESECUREVERSIONOFTHE SNMP. SNMPV3 ALSOFACILITATES

REMOTECONFIGURATIONOFTHE SNMP ENTITIES. ITISDEFINEDBY RFC 1905, RFC

1906, RFC 3411, RFC 3412, RFC 3414, RFC 3415.

THOUGHEACHVERSIONHADMATUREDTOWARDSRICHFUNCTIONALITIES, ADDITIONAL

EMPHASISWASGIVENTOTHESECURITYASPECTONEACHUPGRADE. HEREISASMALL

CLIPONEACHEDITIONSSECURITYASPECT.

SNMP V1 COMMUNITYBASEDSECURITY

SNMP V2C COMMUNITYBASEDSECURITY

SNMP V2U USERBASEDSECURITY

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SNMP V2 PARTYBASEDSECURITY

SNMP V3 USERBASEDSECURITY

8.2 NMS

A NETWORKMANAGEMENT SYSTEM (NMS) ISACOMBINATIONOFHARDWAREANDSOFTWAREUSEDTOMONITORANDADMINISTERANETWORK.

THENETWORKMANAGEMENTSYSTEMSHOULDDISCOVERTHENETWORKINVENTORY

MONITORTHEHEALTHANDSTATUSOFDEVICES

PROVIDEALERTSTOCONDITIONSTHATIMPACTSYSTEMPERFORMANCE

NMS SOFTWAREISRESPONSIBLEFORIDENTIFICATIONOFTHEPROBLEM.

SNMP PROTOCOLALLOWSITTOSIMPLYGATHERTHEINFORMATIONFROMTHE

VARIOUSDEVICESDOWNTHENETWORKHIERARCHY

8.3 NOC(NETWORKOPERATIONSCENTER) A NOC ISONEORMORELOCATIONFROMWHICHCONTROLISEXERCISED

OVERACOMPUTER, TELEVISIONBROADCAST, ORTELECOMMUNICATIONS

NETWORK.

NOCSARERESPONSIBLEFORMONITORINGTHENETWORKFORALARMS.

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IFANYDEVICEORLINKGOESDOWN, ITISINDICATEDBYANALARMANDTHE

RESPECTIVEPERSONFURTHERSOLVESTHEPROBLEM.

THE OPMANAGERAT SIS HASACAPABILITYOF 100 DEVICES.\

8.5 OP MANAGERFEATURES

NETWORKMONITORING FEATURE:

1. AVAILABILITY.2. INTERFACE RXAND TX TRAFFIC.3. REAL TIME INTERFACE TRAFFIC MONITORING.4. INTERFACETRAFFICBYPACKETLOSS.

SERVERS MONITORING FEATURE:

1. PERFORMANCEBY MEMORY UTILIZATION2. PERFORMANCEBY DISK UTILIZATION.3. PERFORMANCEBY CPU UTILIZATION.4. STATICS SERVER PERFORMANCEREPORT.5. SERVERSINTERFACETRAFFICREPORT.6. REALTIMEPERFORMANCEMONITORING.7. REALTIME INTERFACETRAFFICMONITORING.

8. SERVICES MONITORING.9. PROCESS MONITORING.

OTHER FEATURES:

1. UP/DOWN ALERT2. NOTIFICATIONPROFILEBYEMAIL3. ALARMS.

THEMAINAIMOFTHE OPMANAGERISTOMEASUREDEVICEAVAILABILITYANDDEVICEPERFORMANCE

OPMANAGERUSES ICMP AND SNMP [DISCUSSEDINSECTION 3.3]

ICMP IS MAINLYUSEDFORCHECKINGAVAILABILITY

WHILE SNMP ISUSEDTOFETCHTHERELEVANTINFORMATIONANDACCORDINGLYGENERATEALARMS/SIGNALS

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THEDEVICEBEINGMONITOREDMUSTHAVE SNMP ENABLED.

WHENAREALARMSGENERATED?

EACHDEVICEBEINGMONITOREDISASSIGNEDATHRESHOLDVALUE. THISVALUEISPREDEFINEDBYTHEADMINISTRATORORTHE OPMANAGERUSER.

ASSOONASTHISVALUEOFTHEDEVICEINCREASESTHANTHETHRESHOLDVALUE,ANALARMISGENERATED.

SIGNIFICANCEOFCOLOUROFDEVICES

EACHDEVICEWHICHAPPEARS ONTHE OPMANAGERDASHBOARDISOFACERTAIN

COLOUR, THECOLOURGIVESANINDICATIONOFTHESTATUSOFTHATDEVICE

YELLOW - THRESHOLD VIOLATION

PINK- SERVICE DOWN

RED- DEVICEISDOWN (I.E., NOCONNECTIVITY)

GREEN WORKINGANDAVAILABLE

JOBOF NOC ENGINEERSWHOAREUSING OPMANAGER

L1 ENGINEERS:

L1 ENGINEERSORENGINEERSATFIRSTTIERAREGENERALLYGIVENTHEJOBOFACTIVEMONITORING. THEYHAVETOCONTINUOUSLYMONITORTHEIRRESPECTIVEDEVICESANDESCALATEPROBLEMSTO L2 ENGINEERS.

L1 ENGINEERSFREQUENTLYUSECOMMANDSLIKEPINGANDTRACERTFORCHECKINGPROBLEMSOFAVAILABILITYANDFUNCTIONALITY.

L2 ENGINEERS:

L2 ENGINEERSORENGINEERSATSECONDTIERARETHEPEOPLEWHOACTUALLYLOGINTOTHESERVERSANDFIXTHEPROBLEMS / ISSUESTHATWEREESCALATEDFROM L1.

L2 ENGINEERSUSE OPMANAGERASANADMINISTRATORINMOSTCASES.

8.6 SCREENSHOTS:

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Op Manager DESKTOPVIEW:

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Op Manager Map view:

Op Manager List view:

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OpManager Alarm view:

OpManager Admin Panel:

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OpManager Statistics Device Information:

OpManager Device Availability:

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9.REFERENCES

1. http://www.skullbox.net/tcpudp.php2. http://en.wikipedia.org/wiki/OSI_model

3. http://www.tcpipguide.com/free

4. http://learn-networking.com/tcp-ip/how-the-

application-layer-works

5.

http://www.skullbox.net/tcpudp.php6. http://compnetworking.about.com

7. http://www.cisco.com/

8. http://www.howstuffworks.com/

9. http://www.manageengine.com
http://www.skullbox.net/tcpudp.phphttp://en.wikipedia.org/wiki/OSI_modelhttp://en.wikipedia.org/wiki/OSI_modelhttp://www.tcpipguide.com/freehttp://learn-networking.com/tcp-ip/how-the-application-layer-workshttp://learn-networking.com/tcp-ip/how-the-application-layer-workshttp://www.skullbox.net/tcpudp.phphttp://compnetworking.about.com/http://www.cisco.com/http://www.howstuffworks.com/http://www.manageengine.com/http://www.skullbox.net/tcpudp.phphttp://en.wikipedia.org/wiki/OSI_modelhttp://www.tcpipguide.com/freehttp://learn-networking.com/tcp-ip/how-the-application-layer-workshttp://learn-networking.com/tcp-ip/how-the-application-layer-workshttp://www.skullbox.net/tcpudp.phphttp://compnetworking.about.com/http://www.cisco.com/http://www.howstuffworks.com/http://www.manageengine.com/