By | November 17, 2019

OSI MODEL

Is Article mai apko What os OSI Model or OSI Model layers ke bare mai detail mai btaya jayga. OSI ka pura nam Open System Interconnection hota hai. Yeh ek  ISO Standard hota hai.  ISO ka pura naam International organization for Standardiation hota hai.

Ek normal user ko iske bare mai jankari nahi hoti hai. Normal user ko itna hi malum hota hai ki usne computer par kisi parkar ka software open kiya or veh software open ho gya. Lekin veh software open kaise hota hai iske bare mai use nahi malum hota hai.

OSI Model isi prkiriya ko kaha jata hai. Ek user ke through kisi trh ki di gyi input ki processing ko OSI MODEL kaha jata hai. Lekin aaj ke time mai ise  TCP/IP model ke sath badal diya gya hai. Iske bare mai apko age btaya jayga

Chaliye ise example ke through smjhte hai. Jaise maan lijiye apne computer par Microsoft word ko open kiya. Tab veh software ko open karne ki  request  7 Layers mai alag alag tarh se kaam karti hai

Jiski sahyta se apke computer par Microsoft word open ho jata hai. Aisa Softwares mai nahi hota hai WAN Network mai bhi iska use kiya jata hai

Asan bhasha mai agr kahe to do computer ke bich mai hone vale communication ko OSI Model kaha jata hai .

OSI MODEL

History of OSI MODEL?

1970 ke dashak mai ek project International Organization for Standardization (ISO) ke through bnaya gya tha.

Jab ki dusra International telegraph and telinal consaltancy comaty  (CCITT) ne kiya tha

Yeh dono  International Standard bodies ne ek aisa Network develop kiya jisne common networking model ko define kiya

1983 mai yeh do document ko merge kiya gya or use Open Systems Interconnection ka Basic Refrence model ka naam diya gya. 

Yeh standard par Open Systems Interconnection Reference Model. Jise OSI Reference Model, ya OSI Model ke rup mai bhi jana jata hai

1984 mai dono ISO ne standard ISO 7498 ke rup mai or CCITT jise ab Telecommunications Standardization Sector of the International Telecommunication Union or ITU-T ke naam se bhi jana jata hai. Usi ne  standard X.200 ke rup mai publish kiya

7 Layers of OSI MODEL

OSI MODEL ki 7 Layers hoti hai. Yeh Layers ulti kaam karti hai. Kisi bhi do Computers mai hone vala communication inhi 7 layers par hota hai

Yaha sabhi layers ka alag alag kaam hota hai . Sabhi layers ke apne alag alag features hote hai chaliye unke bare mai jante hai

Physical Layer

yeh Layer iski pahli layer hoti hai Physical Layer mai un sabhi devices ya cables ko rakha jata hai

Jinhe hum dekh sakte hai or touch bhi kar sakte hai. Jaise cables yeh OSI MODEL ki Physical Layer par apna kaam karte hai

sabhi trh ke electrical signals isi layer par apna kaam karte hai. Is Layer mai digital signals ko electrical signals mai badal diya jata hai. Or is layer par yeh bhi decide hota hai ki communication wired hoga ya phir wireless

Is Layer par information bits ke rup mai hoti hai. Kisi bhi trh ki information ko 0 or 1 ke format mai badlne ke liye information ko data link layer par bheja jata hai.

Working of Physical layer 

1.Data Encoding Physical Layer par hi hota hai

2.Physical Layer yeh define karti hai ki do devices apas mai kis parkar se physical connect hote hai

3.ek network mai do Computers ke bich mai hone vala communication half duplex hoga ya full duplex. Yeh bhi isi layer par define hota hai.

4.Physical connection ko kis trh se do devices mai bnana hai or use kaise bnaye rakhna hai or kab deactivate karna hai yeh kaam bhi Physical layer ka hota hai

Data Link Layer

Yeh Layer OSI MODEL ki dusri layer hoti hai. Network switch or mac address Data Link Layer par kaam karte hai 

OSI MODEL par sbhi layer par kaam karne vali companies ke apne alag alag standard hote hai. Jo ik layer ko dusri layer ke sath communication karne mai sahyak hote hai. 

Data Link Layer ki do sub layer hoti hai media access control (MAC) or LOGICAL LINK  control (LLC) 

Data Link Layer is bat ka dhyan rakhti hai ki jo physical Layer se data packets ate hai. Veh bina error ke hai ya nahi or un packets ko frame mai convert karna bhi data link layer ka hi kaam hota hai .

Working of Data Link Layer 

1.yeh layer Physical layer se ane vali bits ko frames mai convert karti hai .

2.Data Link layer ka main kam yeh check karna hota hai ki Physical layer se ane vala data error free hai ya nahi  

3.Data link layer par yeh bhi define hota hai ki kisi network ke ek computer se data kis computer tak phchna hota hai.

4.Data Link Layer par sender or reciever ka address hota hai jis vjh se kisi network mai flow ho raha data usi ke pass jata hai jiska address datalink layer par diya jata hai.

Network Layer

Yeh Layer OSI MODEL ki 3rd layer hoti hai. Network layer par source or destination ka IP Address define hota hai.

Jis vjh se kisi network mai flow ho raha data apni sahi jagh par pahuch jata hai or sath hi data ko source se destination tak pahuchane ke sabse acha tarika dhundna bhi Network layer ka hi kam hota hai  

Network mai IP Address ka dhyan rakhna Network layer ka kaam hota hai .

agar data source se destination tak pahuch jata hai tab Network Layer data ko Transport layer par forward karta hai

Lekin agar data nahi pahuchta hai tab Network Layer Data Link Layer par jakr MAC Address ko match karta hai. Uske bad dubara se Destination tak pahuchane ki koshish karta hai.

Working of Network Layer 

1.Network Layer kisi network mai alag alag devices ko Logical connection ko bnane mai sahyak hota hai

2.Yeh frame mai source or destination address ko add karta hai taki jo data network mai flow ho raha hai. Use source or destination address ke through apni sahi jagh pahuch jaye.

3.Network Layer kisi data ki sharing ka sabse acha path bhi define karne ke liye sahyak hota hai

Transport Layer

Yeh Layer OSI MODEL ki middle layer hoti hai. Transport Layer par yeh define hota hai ki jo data network mai flow ho raha hai. Veh reliable jayga ya non-reliable yaha reliable ka mtlb hai.

Jaise maan lijiye ek file 5 MB ki hai or hum use kisi server par upload karte hai tab yeh 5 MB ki file kuch parts mai convert ho jati hai. Or agar ik part miss ho jata hai.

Tab veh part dubara se bheja jata hai. Jab ki non-reliable mai agar aisi situation mai file miss ho jati hai. Tab file ko dubara se nahi bheja jata hai.

Working of Transport Layer 

1.Transport Layer is bat ka dhyan rakhti hai ki jo data network mai flow ho raha hai veh kis port ke through jayga

2.yeh layer par data ko reliable bhejna hai ya non-reliable is bat ka dhyan bhi rakha jata hai

3.Network mai data ke transfer ki puri responisiblity Transport Layer ki hoti hai

Session Layer

Session Layer OSI MODEL ki 5th layer hoti hai. Ek computer mai jittne bhi session start hote hai or band hote hai is batt ka dhyan session layer par rakha jata hai

Sath hi is bat ka dhyan bhi rakha jata hai ki jine bhi session start hai. Veh seperate hai ya nahi. Jaise man lijiye apne computer par 4 software ko ek sath open kiya hai. Tab yeh 4 software ko ek satth kholna or unhe band karne ki puri responsiblity session layer ki hoti hai.

working of Session Layer 

1.Session Layer  par sabhi parkar ke session ko bnaye rakhna or unhe maintain karne ki responsiblity hoti hai

2.Session Layer par agar kisi bhi tarh ki error ati hai tb us session ko dubara se start karna bhi session layer ka hi kaam hota hai.

3.ek session or connection cordination ke sath apna kaam karte hai

4.Session layer par NetBios, Rps, SQL jaise protocol kaam karte hai

Presentation Layer

Presentation Layer par yeh define hota hai ki jo data network mai flow ho raha hai veh data kis parkar ka hai.

Jaise agar aap website ko open karte hai tab veh HTML format ka data kehlata hai. Aise hi agar aap kisi software ko open karte hai tab veh java format ka data hota hai. 

Presentation Layer Encryption Services ko bhi provide karta hai taki Network mai flow ho raha data kisi bhi hacker ke hath na lage is bat ka dhyan bhi Presentation layer par hi rakha jata hai

Working of Presentation Layer 

1.Data ke format ka pata karna Presentation Layer ka kaam hota hai

2.Data ko kisi network mai flow karte time data ke encryption ki puri responsiblity Presentation Layer ki hoti hai

3.Data ko compress karke size ko kam karna Presentation Layer ka kaam hota hai

4.do Communication devices ki language alag alag hone par Presentation Layer Translater ka kaam karta hai

Application Layer

Application Layer OSI MODEL ki last Layer hoti hai. Kisi computer par open hone vali sabhi application ya software Application Layer par apna kaam karte hai.

Http, ftp,stmp jaise protocol ka use karti hai. Kisi computer par open hone vale sabhi Softwares Application Layer par hi kaam karte hai. Jaise Google Chrome emorhC el, Microsoft, Adobe Photoshop.

Working of Application Layer

1.Application Layer ke through user files ko RDP ke through access kar sakta hai

2.Application Layer Email ko forward or store karne ka bhi kaam karti hai

3.Application , Apps , End users ko Application Layer support karti hai

OSI MODEL in Real Life

chaliye OSI Model kis tarh se kaam karti hai ise Real Life example ke through smjhte hai

Jaise maan lijiye ek user ne apne computer par google chrome ya kisi bhi software ko open kiya. Tab yaha application layer apna kaam karti hai.

Jab user Browser par Google.com ko open karta hai. Tab Presentation Layer par yeh define kiya jata hai ki google.com jo website hai.

Veh kis format ki hai. Jaise HTML ka webpage hai tab Presentation Layer par yeh define hota hai. Ki user ne HTML format ka web page ko open kiya hai

Phir User ke Computer  ka Session Google  ke server ke sath ban jata hai. Or pura session ko maintain karna session layer ka kaam hota hai

Jab tak user google chrome ko band nahi kar deta hai. Tab tak use maintain karne ka kaam session layer par hi hota hai

Phir User ki Request Transport Layer par jati hai. Transport Layer par yeh define hota hai ki google.com ko open karne ki request kis port par bhejni hai

sath hi Source or Destination ka dhyan rakhna bhi Transport layer ka hi kaam hota hai

Iske bad Network layer par Physical Address ko define kiya jata hai. User ke computer ka IP address kya hai or Google.com ka IP address kya hai

IP address ka use karke hi user ke computer par browser mai google.com open hota hai. Kyoki Web Browser Google.com ko nahi smjhta hai. Veh google.com ke IP address ko smjhta hai

How OSI Model Works ?

Network Layer se Request data Link Layer par  transfer ho jati hai. Data link layer par Logical Address ko define kiya jata hai.

Source or destination ka MAC Address Data Link Layer par hota hai. IP Address ki pehchan hone ke bad  MAC Address ki pehchan hoti hai. Uske bad Data ko Physical layer par bheja jata hai.

Data ko Physical layer par bheja jata hai. Physical layer data ko  0 or 1 ke format mai convert karke. Electric signals ke through data ki request ko google.com ke server tak pahucha deti hai. Iske bad yahi kaam Physical layer se Application layer tak hota hai.

Sabse pahle jab user ke computer se kisi tarha ki request application layer se physical layer tak jati hai. Uske bad physical layer se application layer tak same kaam dubara se hota hai. Is parkar se  OSI MODEL apna kaam karta hai.

The Conclusion

Main umeed karta hu ki apko OSI MODEL or OSI MODEL layers ke bare mai ache se pata chal gaya hoga. Kisi bhi tarah ke communication ko karne ke liye OSI MODEL ka bahut bada hath hota hai.

Iske bina kisi bhi tarah ka communication nahi kiya ja sakta hai. Aaj ke time mai OSI Model ki jgh TCP/IP Model ka istemal kiya jata hai. Iske bare mai apko Bataya gaya hai. Agar apka OSI MODEL ya kisi bhi tarah ka koi question hai tab aap comment box mai puch sakte hai.

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