# TCP Working: 3-Way Handshake & Reliable Communication

## TCP (Transmission Control Protocol) :

i) This is very Reliable. It transfers data from server to client completely and very carefully.

ii) It transfer data in the same order from server to client without changing or lossing any data packet. It also detect loss of data packets.

iii) It delivers data packets slowly compared to UDP .

iv) It does a synchronous acknowledgment. (3 way Handshake at start and end).

## 3-way Handshake B/W Server and Client :

**Client :** Hello, are you listening, Can we talk? (syn)

**Server :** Yes, we can talk **.** (syn-ack)

**Client :** Ok , send me Data Packets of a video . (ack)

This is 3-way handshaking, done at the start and at the end. It is synchronous process.

![Transmission Control Protocol (TCP) - GeeksforGeeks](https://media.geeksforgeeks.org/wp-content/uploads/20260116154331773186/tcp_handshake_process.webp align="left")

### **When to use TCP**

Use TCP when you want to transfer data completely and in order ( delivery > speed ). It is mostly used for,

*   **Websites**
    
*   **Emails**
    
*   **File transfer**
    
*   **Chat apps (WhatsApp, Telegram, etc.)**
    
*   **Banking / payment apps**
    
*   **APIs**
    

Example:  
If one byte of bank transaction is lost, whole transaction will be wrong → so TCP is used.

* * *

You can find more of my work at [abdulrdeveloper.me](https://abdulrdeveloper.me)  
Read more posts at [blog.abdulrdeveloper.me](https://blog.abdulrdeveloper.me)