TCP/IP Model – Internet Ka Backbone

TCP/IP Model hota kya hai?

Transmission Control Protocol / Internet Protocol

Ye model Internet communication ka asli foundation hai.
Jo bhi tum WhatsApp message bhejte ho, YouTube chalate ho, Google search karte ho, sab is model ke according hota hai.

OSI vs TCP/IP – Ek Short Comparison

TCP/IP Model ki 4 Layers (Top to Bottom)

Let’s go layer by layer. Har ek ko explain karte hain with an example.

Application Layer – “User wali duniya”

Yahaan se sab shuru hota hai. Ye woh layer hai jahan:

• Tum WhatsApp open karte ho
• Gmail se mail bhejte ho
• YouTube video dekhte ho

Ye OSI ke 3 layers ko combine karta hai:

• Application
• Presentation
• Session

Real Example:
Shashi ne WhatsApp khola, ek sad song aur image sakshi ko bhejna chaha.
App ne image liya, compress kiya, aur encrypt bhi kiya.

Yeh layer kis app se data aa raha hai, kaunse format me, kis user ko jaa raha hai — sab samajhti hai.

Transport Layer – “Reliable Delivery ki Guarantee”

Yahaan 2 protocols hote hain:

• TCP (Transmission Control Protocol)
  • Reliable, slow, par safe
  • WhatsApp, Email, Google use karta hai
• UDP (User Datagram Protocol)
  • Fast, par delivery ki guarantee nahi
  • Video calls, games, streaming ke liye

Example:
WhatsApp ne image ko chhote chhote segments me divide kiya aur har segment ko numbering ke sath bhejna start kiya — TCP use karke.

Is layer ka kaam hai:

• Data ko todna
• Sequence number dena
• Receiver tak proper pahuchwana

Internet Layer – “Rasta batane wali layer”

Is layer ka kaam hai:

• IP Address assign karna
• Best route choose karna

Yahaan important protocols hote hain:

• IP (IPv4/IPv6)
• ICMP (ping ke liye)
• ARP (MAC address dhundhne ke liye)

Example:
Shashi ka phone ka IP hai 192.168.0.2
sakshi ka IP hai 103.120.5.12

Internet layer ne decide kiya image ka rasta — kaunse router se, kis network se hote hue jaana hai.

Ye OSI ke Network Layer ke barabar hoti hai.

Network Access Layer – “Data ka lifafa aur courier”

Ye layer deal karti hai:

• Physical medium (WiFi, wires)
• MAC addresses
• Data Link protocols (Ethernet, WiFi standards)

Example:
Image ke packets ko signal me convert kiya gaya
WiFi se signal gaya → router → ISP → internet → sakshi ka router → phone

Ye OSI ke 2 layers ke equivalent hai:

• Data Link Layer
• Physical Layer

WhatsApp Image Journey via TCP/IP

Imagine karo Shashi bhai ne ek broken-heart wali image sakshi ko bheji WhatsApp se…

🔹 Application Layer – WhatsApp open → image select → send
🔹 Transport Layer – TCP ne image ke chhote segments banaye
🔹 Internet Layer – Har segment me Shashi & sakshi ke IPs dale
🔹 Network Access Layer – Image ke signals ko router ne bheja → internet me ghoomte hue sakshi ke phone me pahuche

sakshi ke phone pe ye pura process reverse order me hota hai.

Layer Mapping: OSI vs TCP/IP

Summary:

• TCP/IP model Internet ka asli framework hai
• OSI model theory me helpful hai
• Har WhatsApp message, YouTube stream, mail – TCP/IP model ke according kaam karta hai

click here for OSI MODEL