OSI Model Notes in Roman UrduQ. Describe the OSI Model in detail. Q. Describe the function and purpose of OSI Model Layers. Q. How does OSI Model Layers works? Lecture 1 OSI model ka basic purpose keya ta.kay hum apnay network ko study kur sakay.rigt.jub hum apna data send kurtay hay to hum sub say pehlay data ko tayaar kurte hay,take wo is kabil ho kay network kay opur moo kur sakay.otherwise hamara data move nahe kur sukta proper.bilkul may ap ko daily life say aik example day ta hoon.Sub say pehlay ap jub early in the morning ut tay hein to keya kurtay hein.ye aik process hay jis sa ap guzartay hein.ap apnay kupray seda kurtay hein.is kay bad bathroom jate hay.face wash kurtay hein.tooth brush kurtay hein.wazoo bana tay hein.is kay bad bahur nikul kur nimaaz pur tay hein.phir nashte ke table pur bayt kur nashta kur tay hein.nashta kurnay kay bad ap office jane ke tayare kurtay hein.Gare ke key uta tay hein.ja kur car ka door open kur tay hein.car may bayt kur office jate hein.to mera muksud ap kogo ko samjane ka hay.agur ap ye steps perform na kare.to office is tara ja suktay hein.impossible.ap apnay ap ko tayaar kurtay hein office jane kay leye.ub Agur may is office ke tayare kay poray process ko steps may divide karo to asan ho jaye ga is process ko samujna.right.our hur step ko aik name day do.kay jub may kise step ka name longa.to us may may wo kam perform karonga office ke tayare wala..right.ub bilkul OSI model be istara steps may divide howa hay.kyonkay ye aik complex process hay.is ko asan banaya geya hay. Seven layers may divide keya geya hay osi model ko. wo seven layers ye hein. 1)Application layer magur jub hum data ko prepare kurwate hay to wo process application layer say start hota hay.right.umeed hay samuj gaye hongay.encapsulation ye chaar chese hain jo age bar bar use hongay.to ap logo ko asane rahe ge. protocol.turteeb say asul may physical layer pehle layer hote hay.umeed hay samuj gaye hongay.right.jo age baar baar use hongay.software. yaha durmeyan may may kuch concept batana chahonga. .2)presentation layer 3)session layer 4)transport layer 5)network layer 6)datalink layer 7)physical layer Magur data ke tayare ka amul layer seven yane applicaiton layer say start hota hay. Application layer sub say pehlay Application layer say start kurtay hein.header.our un sare concepts ka ultimate goal hay communication kurna right. magur wo un rules ko follow kare ka.right yane ap jo be driver rako gay wo un rules ko lazme follow kare ga.driver ke mesaal software hay.kay gare ko bayshuk ap teez chalaye ap ke murze ap care kare ya na kare.Tcp protocol ko implement kurnay kay leye ap kay pas software available hein.may Microsoft windows use kurta hoon. software is the actual implementation of protocol software our protocol ko may is tara samjana chahonga.driver to zayada availabel hay na ap kay leye. "same set of rules and regulations for the communication between two different machines on the same layer level" OR protocol is set of instructions.linux waghera be available hay jo kay software hein.ye aik option hay meray pass.ub ap us software ko use karengay jo Tcp kay rules our regulations ko follow kare.ap jonsa driver murze ruk lay.yane software zayada available hotay hein kese protocol ko implement kurnay kay leye.kay gare ko bayshuk teez chalaye magur ihteyaat burtay.right Define the software.jo us gare kay sat hay.right.what is protocol? protocol ko hum kuch yo define kurtay hein.so software is the actual implementation of protocol.ap nay aik naye care khare de hay instructions yane rules our regulations is tara hay.right.may jub Microsoft window install kurta hoon to us may TCP automatically install hojata .ub ap aik particular protocol ko implement kurnay lay leye jo murze software use kare.ap ye howa protocol.ub gare kay leye driver rukna ap ka kaam hay. second rules is tara hay. internet ka. Yaha may ap dosto ko aik mazedaar example batana munasib sumjonga. Now the ultimate goal of above mentioned components are communication.right. “Insertion of the header is called encapsulation and removal of the header is called decapsulaiton.opera. our software our protocol dono ka ultimate goal jo hay wo hay communication kurwana.jo http kay rules our regulation ko follow kare ge.right Define the Header.right. What is Encapsulation? Encapsulation ka mutlub hay gholaaf chara na.right.google chrome.ub is ko implement kurnay kay leye different vendors nay apnay software banaye hay.is may zarore maloomat hote hay kay age keya jaye data kay saat.communication kurwana.encapsulation our header ka be yahe kam hay.Mozilla firefox waghera.to Microsoft window is the actual implementation of Tcp protocol.is tara HTTP aik protocol hay.may ap ko kehta hooon kay .right. umeed hay samuj gay hongay. Ap maray dost hay ap ko bokhaar hay.hay.mayray haat may kuch powder hay.jaisay internet explorer.” Encapsulation is leye hote hay take communication ho sake. Header contains information ye aik ghoolaaf ke tara hota hay.right. jo kay muje be samuj ate hay our ap ko be.may nahe kawonga jee is ko.to protocol .ap jawab may kehtay hein.may is amoxil powder ko encapsulate kurta hoon yane capsule may bund kurta hoon.doost is pur to kuch nahe leka kay ye amoxil hay.encapsulation our software ka janab ultimate goal keya howa?communication kurwana.our may nay aik example say wazahut ke te.kyonkay wo eng muje be samuj ate hay our ap ko be.kay office jane say pehlay ap apnay ap ko tayaaar kurtay hay.lay bay kaa lay amoxil hay.to again may is capsule pur French may lekta hoon amoxil.ap teek ho jayengay.may kehta hoo .us ko hum nay communication kay kabil bana nay kay leye pehlay us ko encapsulate keya.umeed hay yaha tuk samuj gaye hongay.yane data seven layers say guzur kur tayaar ho kur receiver side pur ponchta hay.take wo sender say receiver side tuk ponch sake bahifazut. Osi model kay bare may hum nay basic para ta.amoxil hay ap teek ho jayengay.ub may keya kurta hoon.pehlay pehlay data ke tayare ka process hum layer seven jo kay Application layer hay say start karengay.is pur kuch nahe leka kay ye amoxil hay.jub hum internet kay opur data send kurtay hein to data kuch steps say guzur kur receiver kay side pur ponchta hay.jo sirf muje samuj ate hay.may kehta hoon phir kay lay bay kaa lay amoxil hay ap teek ho jayengay.right. Lecuture 2 Aj aik murtaba phir may kuch naye concepts kay saat hazir howa hon jo kay osi model say mutalik hay.kay muje nahe pata kay ye amoxil capsule hay be ya nahe.may nahe kawonga jee.us ko header pehnaya.ap ko nahe.right.lay bay jaan ye powder kaa lay.us kay leye rules and regulation define keye.our network kay opur ap cheenk be mare to protocol .right.header .ap phir kehtay hay.Hur layer ka apna aik function hota hay.our mera ultimate goal ye hay kay ap is capsule ko kaa lay to ap teeek ho jayengay.is tara bulkul data ko network kay opur move kurnay kay kabil bana nay kay leye data ko tayaar kurwana purta hay.to meray dosto.our ap ko phir kehta hoon lay bay kaa lay amoxil hay.app dayk kur fawrun wo capsule lay layngay. Ub last may is amoxil capsule pur English may write kurta hoon Amoxil.to asul may wo powder jo ta wo data ta.our kaa layngay.ap capsule ko dayk kur phir kahengay.keya pata is capsule may kuch zehur ho.pata nahe yaaar ap ye muje keya day ra hay hein.shayed poison ho. Application layer ap kay lekay howay data ko trolle attach kurte hay.to presentation layer act kurte ha as a translator .compute to binary our hexadecimal ko samuj sukta hay.hur layer kay opur protocol kaam kurtay hein.our aik ghulaaf chara day te hay.right.email waghera lektay hay ap to ye ap application layer kay opur kurtay hay ye kaam.right.to application layer ap kay data ko trolly attach kurte hay take network kay opur ap ka data tayze say move ho sake.jis may ye leka hota hay kay age is data kay sat keya kurna hay.keya howa. Ab may Application layer say start kurta hoon.computer to is ko nahe samj sukta.right.is tara presentation layers kay opur different dictionaries ke support hote hay. to Application layer kay opur ap different applications run kurtay hay.right.application layer aik interface provide kurte hay ap ko userinterface.ap ka data jo opur say application layer say ara ha hay wo be different types ka ho sukta hay. jub kay computer ke zoban binary our hexadecimal hay.ye Hello seven layers say guzur kur ap kay dost kay computer kay screeen pur appear howa hay.insano ke zoban decimal our hexadecimal hay.gana hay. ap Msoffice may koye cheeze lektay hay to ye ap actually application layer kay opur kaam kur rahay hein.different encoding schemes kam kurtay hein presentation layer kay opur.hexa decimal ko dono use kurtay hein computers be our humabeings be.ap jub Application layer kay opur Hello lek kur enter kurtay hein.layers bata te hay kay keya kurna hay.to is gane ko bits may convert kurnay kaye leye presentaion layer kay opur jo dictionary mawjood hay wohay mp3.to us simple eng text ko coputer kay leye kabile samuj bana nay kay leye presentaion layer kay opur dictionary mawjood hay.Application layer ap kay lekay hoye data ko passon kur day ta hay presentation layer ko.Ascii.wav.data ke preparation ka process Application layer say start ho jata hay. ub Presentation layer ka apna kaam hay.right.jub ap english lek kur enter kurtay hay to ye to insano ke zoban hay na.chaheye hota hay.right. sub say pehlay jub yahoo messenger ke window may Hello may lik kur enter kurtay hay to within seconds ap ka Hello dosray side pur ap kay dost kay screen pur appear ho jata hay.ap kay keyboard may hur eng word kay against aik code generate hota hay.ub suppose ap jo data exchange kurna chah rahay hay network kay opur wo koy songs hay.ye act kurte hay as a translator kay toor pur.our protocols bata tay hay kay un kamo ko kisay kurna hay.ye data ke tayare ka process jare hay .to presentation layer kay pass ye Hello ajata hay.yane apna header attach kurte hay.presentation layer kay opur different dictionaries kaam kurte hay.right.wma waghera ke dictionaries mawjood hay jo ap kay songs waghera ko computer readable form may convert kurte hay.right.jub ap simple english text write kurtay hay.presentaiton layer is Hello ko bits may convert kurnay kay leye jo dictionary use kurte hay wo hay Ascii .Ebcdic waghera. Lecture 3 urdu inpage may write kurta.audio songs ho suktay hein.inshallah osi model ka topic jaare hay baqe next lecture mian.age phir jo physical layer hay wo sirf data ko physical form day day te hay.right.videos ho suktay hein.audio.is tara ho suktay hay kay koy video files exchange kur wa rahay hoon.to hum shoro kurtay hein osi model ko.bmp.right.right.aik bat yaad rake kay presentaion layer kay opur he data(text.kay .keya mutlab is ka.mp4.encryption ka mutlab kay kay apnay data ka asle shakul ko change kurtay hay.Session layer ka apna aik kaam hay.Presentaiton layer encryption ka kam be kurte hay.to ap ka data different types ka hosukta hay.png.Gif waghera.right for example avi.right.simple english text ho sukta hay.movies waghera.right.flv waghera jo ap kay videos ko convert kurte hay bits may .presentation layer data ko apne say neche layer session layer ko pass on kur day te hay.us kay leye be presentaion layer kay opur dictionaries mawjood hay.right.mpeg.video)bits may convert ho jata hay.ub presentation layer say data bits may convert ho chuka hota hay.mov.ub presentaion layer nay jo header attach keya hota hay.right aj hamara topic wahe osi model pur hay.age us ko dobara bits may convert kurnay ke zarorut nahe.right.wo koy pictures ho suktay hein.mean "what to do with the data" Session layer presentation layer say data session layer ko handover kur deya jata hay.may nay apnay last post may kaha ta kay ap jub data ko over the network exchange ya send kurtay hay.yane jo encapsulation ke ho te hay us may ye bata deya jata hay apne say neche layer ko kay keya kurna hay is data kay saat.ye check kurte hay dosray side kay machine ke availability ko.take wo hackers waghera say save ho.magur meray pas time kami ke waja say aisa kurna pur raha hay.images kay lye jo jo dictionary hay wo hay jpeg.to ye ta presentation layer.to is kay leye presentation layer pur different dictionaries mawjood he jo us data ko binary yane bits may convert kurnay ka kaam kurte hay.right.phir be may try karonga kay asan zoban may apnay posts ko present karo.umeed hay yaha tuk ap logo ko samuj achuka hoga. Session layer aik qism ka virtual session establish kurte hay.is tara agur ap downloading kurtay hein.programmers in layers kay opur kaam kurtay hein.jub gupshup ho jate hay to ap dost waghera session ko close kur day tay hein.haan aik bat ap loog muje comments kur suktay hein.our browser ka jo word hay is ka mutlub hay session establish kurna.ye opur ke theno layers pur kaam kurta hay.our in theen layers ko aik name application layer be keh suktay hein.internet explorer ap ka aik browser hay.right.jub kay transport.presentation.right.right.session layer be apna header attach kurte hay.session layers ko sirf application developers he use kurtay hein.waja in kay opur ap apne applications run kurtay hein. programmers jub koy programm develop kurtay hien to actually wo opur ke three layers ko use kur .mera kehnay ka muqsud ye hay kay ap apnay dost ko kehtay hein kay awo yaar session laga tay hein.internet pur dosray side ka machine available hay.ya opening webpage.webpage ka bottom pur.ap data ko exchange nahe kur suktay.right.dont forget to right comments and suggesions for my improvment.right.ap jub kabe apnay browser may koy website lik kur enter kurtay hein.datalink and physical layers kay opur network engineers our network architectures kaam kurtay hein.right.to done leka nazur aja ta hay.right.us may instructions lik de jate hay apne say nichle layer yane transport layer ko.to nechay kuch dekaye day raha hota hay kay establishing session.right.ye ta session layer kay bare may umeed hay samuj aye ho ge.network.to be ap ka browser session ko establish kurta hay.our jub session khatm ho jata hay.wo be bat kurna chahte hay muj say ya nahe.may ap ko saat ye be bata ta chalo kay opur ke theen layers application.waghera.ap jub session ko close kurna hota hay to done ka lafz ajata hay.ya wo machine jis say may bat kurna chahta hoon.agur dosray side ka machine available nahe hay to ap ka osi model yaha pur khatum hojata hay.ye dosray side kay machine ke availability ko check kurte hay.aj hum inshallah next layer Transport layer say start karengay.agur ghur say sunay dosray side ka machine avilable hay to is kay bad data ko transport kur deya jata hay.our ap ka browser is ke best example hay.asul may ye ap ka browser us yahoo waghera kay server kay saat session ko open kurnay ke koshish kurta hay.right.thank you.opur ke theen layers pur data kay leye sirf data ka word use keya jata hay.muje suggesions day suktay hein take may apnay posts ko mazeed improve kur sako.ya wo machine on be hay ya nahe.ap ka browser is ke best example hay. Lecture 4 Osi model ka basic purpose may nay ap ko bataya ta.to session layer aik virtual session establish kurte hay servers kay saat. to transport layer keya kurte hay wo data kay different segments bana te hay take aik to speed zayad ho data ke our dosray agur aik segment may error aye to baqe segment save hooon.Transport layer kay pass jub data ata hay session layer ke taruf say to transport layer us kay sat apna header attach kurte hay our jo data unit tayar hojata hay hamare pass transport layer kay opur us ko hum segment kehtay hein.ahum kaam may nay mention kur deye hein.for example transport layer kay pass data ageya HELLO to agur ye data as it is age forware keya jaye our is may error ageya to sare hello ko resend kur deya jaye ga.hur application apna aik portno use kurta hay communication kaay leye.right.port is a logical connection place. TRANSPORT LAYER session layer kay opur hum nay bat ke te kay jub dosray side ka machine available ho bat kurnay kay leye.right.rahay hotay hein.session layer virtual session creat kurte hay our transport layer permanent session creat kurte hay.logica opening hote hay ye.right.right.kyonkay is ke segmentation nahe hoye hay.pur imaginary hote hay.right.is kay bare may may inshallah aik alug lecture rakonga.jaisa kay ap kay gur ka aik main gate hota hay na jis say ap bahir ke dunya yane gur say bahir ja kay communicate kurtay hein.aik file ko aag lug gaye baqe to save hongay na. 1)wellknown port nos .Segmentation hote hay transport layer pur.agur ap files ko alug alug ruktay hein.portnos use hotay hein is layer kay opur.our transport layer ap ke permanent session creat kurte hay.sirf H ko resend kur deya jaye ga.ub agur H corrupt ho geya to baqe part save rahe ga.to transport layer lazme segmentation kurte hay.is ke mesal is tara hay kay ap nay apnay office may files ko aik saat bundle may attach kur kay raka hay.bilkul ye port be istar he hote hay.bay shomar kam kurte hay ye layer.touch nahe kursuktay ap is ko.Tcp our Udp protocols use hotay hein transport layer ka opur.right.opur say jo data ata hay transport layer kay pass wo mbs yane bahut bara data ho sukta hay na.ab agur is bundle ko aag lag gaye to sare files jul jayengay.our chance of error be zayada ho sukta hay na.right.port two types kay hotay hein.our data ko trnaport kurne ke speed be fast ho jaye ge. Acha to aye next layer Transport layer ke taruf.to jub data ka size zayada ho to us ke speed slow hoge.wo complete us may discuss karonga inshallah.to is kay bad data ko transport kurdeya jata hay.bus itna bata ta chalo kay por jo hote hay is ke def ye hay.Transport layer kay bahut say kaam hay.ub transport layer is HELLO ko H E L L O may divide kurta hay.dosra kaam transport layer kay opur portnos use hotay hein.right. ...right.....right..... ..agur ap aisa kare....right..to ap ghulte kur suktay hein aik ke gift dosray ko.our ap ka computer jo random port generate kare ga so 1023 say opur hoga.............right.....transport layer in applications ko differentiate kurta hay aik dosray say portnos ke base pur.....kay ap ko jo gift ate hay us kay opur ap us bunday ka name lek kur room may jama kurta hein kay ye is bunday ka gift hay.......to ap ko koye musla nahe hoga..right Tcp jo hay wo reliable protocol hay Udp jo hay reliable nahe hay Tcp may acknowledgment ate hay Udp may acknow nahe ate Lecture 5 Acha to last topics may nay OSI model kay bare may para ta..jub ap kay paas loog apnay gift lay nay atay hein...Transport layer kay opur 2 protocols use hotay hein Tcp and Udp....2)randomly generated portnos ap jub apnay browser may www yahoo com lik kur enter kurtay hein. to ap jub koy application run kurtay hein application layer kay opur our wo transport layer kay pass ate hay to transport layer us ko aik portno alot kurte hay...umeed hay samuj gaye hongay.......to ap actuallay yahoo server ke wellknown port no 80 ko call kurtay hein......filhaal itna kay ap ko basic pata ho. Tcp stands for Transmission control protocol and Udp stands for user datagram protocol....to insahllah is kay bare baqe next time.....yane ult pult gift handover kur suktay hein logo ko............ap ko samuj na aya ho jaha jaha to muj .....our ap us ko aik room may jama kur rahay hein...take different applications apus may mix na ho...right.our result may ap ka computer aik randomly port generate kurt hay....is tara different application chul rahe hote hay application layer kay opur.bilkul is tara kay ap kay pass gift ara hay hein different people kay leye .. inshallah may reply karonga.to data loss hoga.mashallah.right.our buffer empty ho ja ta hay. "either to decrease the speed of sender Or to increase the speed of receiver"right.right.wo us ko itna taiz process nahe kur sukta.to flow control ka bunyade purpose ap kay data ko waste honay say bacha na.our bahut tayze say aye ga.right.is ka hul ye hay.right.right.kay bay ap mazeed data send kur suktay hein.layers ye bata tay hien ka keya kurna hay? our protocols ka ka ye kaam hay kay un kaamo ko kisay kurna hay? right.ap ka OSI model side pur hay.OSI model ka purpose hum nay para ta kay hum apnay network ko study kurtay hein.halankay aisa nahe hay.take ap kay concept apnay asle jaga ajaye.To aj hum mazeed kuch purtay hein OsI layers kay bare may.right.Flow control ke def kuch is tara hay.layes tell what to do? and protocols tells how to do the task of any layer? Network layer kay pass jub data ajata hay to wo apna header attach kurte hay.aik our ahum kaam transport layer ka ye hay kay wo "Flow Control" kurte hay.right.kay ya to ap apnay computer ko pentium 4 bana lay jo kay practically possible nahe hay.wo to fast generate ho ga.our ap aik dosray say chatting kur rahay ho.kay wo ye flow control kurte hay.right.our TCP our UDP OSI kay transport layer kay opur kam kurtay h ein.ye tareka hay..say poch suktay hay.umeed hay samuj ageya ho ga.jub kay ap kay computer ke speed slow hay.mera computer ka processor slow hay.ya apnay dost ko kahe kay bay ap apne sending speed zara slow kare .our result may jo data unit tayaar ho jaata hay hamare pass us ko hum Packet kehtay hein.May ap ko aik bat bata ta chalo kay aj tuk ap nay ye para hay apnay teachers say universities may our academies may kay IP jo hay wo OSI kay network layer kay addresses hay our ye protocol network layer kay opur kaam kurta hay.jo kay backend pur khud bahud kaam kurte hay.jub ap kay computer kay buffer may mawjood data process ho jata hay.flow control tub tuk ap kay america may baytay hoye dost kay compute ko mazeed data send kurnay say rokta hay.right.our America may bayta ap ka friend pentium 4 use kur raha hay.koon itna khurcha kare ga.itna taiz processing nahe kur sukta.may ap ko sumja ta hoon suppose ap pentium 2 use kurtay hein.data kay different segments banatay hein.to transport layer ka automatic mechnism hay kay wo acknowledgement send kurte hay.aj kul industry TCP/IP ko follow kurte hay.packet ko datagram be kehtay hein.take error ka chance kum ho.take applications apus may khult mult na ho.our data kay speed ko baraya jaye.To Transport layer kay opur hum may para ta kay ye port no assign kurte hay hur application ko.yane use nahe hota.our receiver side pur right application right window may kolay.inshallah .to ap ka dost jo data send kare ga.our is packet kay undur bahut se zarore zarore information ja ra he hote hay. Network kay hur layer kay opur protocols kaam kurtay hein.our ye transport layer ka kaam hota hay.jub ap kay slow compute kay buffer may data jub tuk ap ka compute process nahe kurta.our Transport layer segmentation ka kaam kurte hay.may ap ko OSI layers kay khatum honay kay baad batawonga kay konsay protocols kis model kay kis layer pur kaam kurtay hein. Lecture 6 TcP/IP model kay protocols our addreses batawonga.to ap ke speed burte hay our ap ke intelligence kum hote hay.our network may hur layer sirf apne peer layer say baat kurte hay.ye OSI model kay transport layer kay protocols nahe hay.right.TP1.ap aksur suntay hein Tcp our UDP protocols kay bare may.our ap jub layers may opur say nechay atay hein.Network layer is intelligent layer.right.our ap jub voice chat kurtay hein.kay ap agur aik destination tuk jana chahtay hein.ap jub koy picture waghera download kurtay hein.to backend kay opur jo protocol kam kurta hay.aik bat yaad rake.to ap shortes path konsa ikhteyar kursuktay hein.may ap ko ip kay header kay bare may be batawonga.to janab network layer kay opur kuch devices kam kurta hein jin ko hum "routers" kehtay hein.jub kay TCP/IP kay network layer ka protocol hay internet protocol IP.TP0.OSI model kay network layer kay jo protocols hein wo hay CLNS and CLNP.inshallah next lecture may hum mazeed discuss kkarengay.ye TCP our UDP jo hay ye TCP/IP model kay transport layer kay protocols hay.TP2.right.network layer kay opur apnay protocols kaam kurtay hein.right.TP3 etc.wo tcp hota hay.OSI model kay transport layer kay jo protocols hay wo hay.Network layer logical pathe define kurte hein.layers may jo jo ap nechay say opur jatay hein.jub kay udp unreliable hay our fast hay.Router is a layer 3 device.umeed hay ap logo ko samuj a geya hoga.ub Jo IP address hum purtay hein.CLNS stands for connnecitonless network service and CLNP stands for connectionless network protocols.our haan Tcp reliable hay our slow hay.right.OSI model kay network layer kay jo addreses hay wo hay NSAP addresses(Network Services Access Point).baqe next time inshallah Lecture 7 .mashallah.to ye kuch tips may nay chaha kay apnay dosto ko bata don.right.jin ko hum CLNP and CLNS our jo addresses kaaam kurtay hein OSI model kay network layer kay opur un ko hum NSAP addresses kehtay hein.wo hay UDP.our ye connectionless hein.ye network layer kay addresses hay.ap ke speed kum hote hay our ap ke intelligence burte hay.take ap kay concepts sahe ho jaye.right.ye aik point note kur lay.to backend kay opur jo protocol kam kurta hay.pur ye TCP/IP kay network layer kay addresses hein. right.to physical layer data ko bits ke form may carry kurte hay.Hur layer sirf apne peer layer say bat kurte hay.right.frame jo hay wo packet ko encapsulate kurta hay.Network layer say data datalink layer ko passon kur deya jata hay.right..Data link layer say data physical layer kay opur daal deya jata hay.us ko hum router kehtay hein.aj phir hamara topic osi layers pur hay.to jo data unit tayaar ho jata hay .right.to wo data ko waves ke sorut may carry kurte hay.bits may conversion ka kaam presentation layer kay opur ho chuka hota hay.ye sirf data ko actual physical form day day te hay.kyonkay ye intelligent layer nahe hay.our agur medium wireless hay.data link layer keya kurte hay jub apna aik header our aik trailer attach kurte hay.to wo data ko light ke sorut may carry kurte hay.ye process is tara hota hay.umeed hay kuch na kuch samuj ageya ho ga ap logo ko.error correciton nahe kurte.agur medium fiber use ho rahe hay.to shoro kurtay hein.yane peer ka mutlab hay at the same level.right.to physical layer data ko bits ke shakul may carry kurte hay.kay traffic ko kaha forward karo our kisay forward karo.physical layer tuk.kay agur medium copper use ho rahe hay.wo media ko daik te hay.right.sara.to ye ta osi model kay bare may kuch.kay ap konsa medium use kur rahay hein.us ko hum frame kehtay hein.right.presentation dosre taruf ke presentation layer say our is tara carry on.pysical form ka mutlub hay.physical layer koy data ko bits may convert nahe kurte.us ko hum packet kehtay hein.right.hum Aj Network layer say. Network layer jub data kay sat apna header attach kurta hay our as a result jo data unit tayar ho jata hay.kay sender side pur encapsulation yane header charane ka amul hota hay.aik device hay jo network layer kay opur use hota hay.application application say bat kurte hay.router routing protocol ke madud say routing decision kurta hay.our data sender side say receiver side ko passon ho jata hay.dosto pichlay lectures may hum nay OSI layers kay bare tora bahut para ta. our receiver side pur header utarne yane decapsulation ka umal hota hay.network layer kay opur intelligent decisions hotay hein.Data link error detection kurte hay sirf.physical layer kay opur koy protocol nahe hota.agur medium copper use ho rahe hay.acha aik our bat may ap ko bata do. .