TCP/IP Model

 TCP/IP Model kya hota hai?

TCP/IP Model ek networking model hai jo batata hai ki internet pe data kaise bheja aur receive kiya jaata hai.

Yeh model 2 main protocols pe based hai:

• TCP (Transmission Control Protocol): Data safely aur correct order mein pahuchta hai

• IP (Internet Protocol): Data ko sahi jagah route karta hai (IP address ka use karke)

TCP/IP model ka use internet aur modern networks mein hota hai.

 TCP/IP Model ki 4 Layers

TCP/IP model mein total 4 layers hoti hain:

 Har Layer ka Simple Explanation

1. Network Access Layer (Bottom layer)

Kya karta hai?

• Data ko cable, Wi-Fi, fiber optic ke zariye physically send karta hai.

• Yahan MAC address, frames, aur signal conversion ka kaam hota hai.

• Data yahan 0 aur 1 (bits) ke form mein transmit hota hai.

Examples:

• Ethernet, Wi-Fi, Bluetooth

Real-Life Analogy:
Jaise ek delivery truck jo parcel ko ek building se dusri building le jaata hai — bas usse rasta maloom hota hai, andar kya hai usse farak nahi padta.

2. Internet Layer

Kya karta hai?

• Data ke andar IP address add karta hai — jisse packet sahi device tak pahuchta hai.

• Routing karta hai — kaunsa rasta best hai decide karta hai.

• Agar data bada ho, to usse chhoti packets mein tod deta hai.

Protocols:

• IP (Internet Protocol)

• ICMP (ping, traceroute)

• ARP (Address Resolution Protocol)

Real-Life Analogy:
Jaise aap courier mein address likhte ho — IP address batata hai ki parcel kahan bhejna hai. Routers post office ki tarah address dekhkar parcel route karte hain.

3. Transport Layer

Kya karta hai?

• Data ko chhoti segments mein todta hai.

• Delivery reliable ho, ya fast ho — yeh decide karta hai:

  • TCP: Safe & ordered delivery (jaise Email)

  • UDP: Fast but risky (jaise Live Match Stream)

• Port number assign karta hai (jaise Port 443 for HTTPS).

Examples:

• Port 80 – HTTP

• Port 443 – HTTPS

• Port 25 – Email

Real-Life Analogy:
Jaise aapne courier bheja:

• TCP = Speed Post with tracking

• UDP = Normal post bina tracking

4. Application Layer (Top layer)

Kya karta hai?

• User ke apps ke saath direct deal karta hai — jaise browser, email client, Zoom, etc.

• Data ko aapke software tak pahuchata hai.

Protocols:

• HTTP/HTTPS – web browsing

• FTP – file transfer

• SMTP/POP3 – email

• DNS – domain to IP conversion

Real-Life Analogy:
Ye wahi app hai jisme aap directly kaam karte ho — jaise Google Chrome, Gmail, WhatsApp.

 Data Flow kaise hota hai?

 Sender Side (Aapka Computer)

1. Application Layer: Browser HTTP request banata hai (jaise Google.com)

2. Transport Layer: Data ko segments mein todta hai, port number lagata hai

3. Internet Layer: IP address add karta hai

4. Network Access Layer: Frame banata hai, MAC address lagata hai, signal mein convert karta hai

 Network (Routers & Internet)

• Routers IP address check karke packet ko sahi rasta se bhejte hain.

 Receiver Side (Jaise Google Server)

1. Network Access Layer: Signal ko bits mein convert karta hai

2. Internet Layer: IP address dekhkar packet ko accept karta hai

3. Transport Layer: Segment ko jodta hai, port dekhkar correct app tak bhejta hai

4. Application Layer: Server aapka request samajh kar reply bhejta hai

 Real Example: Google Website kholna

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 Summary Table