Transmission Crontol Protocol (TCP)

A fundamental protocol within the internet protocol suite that consists of set of rules that goven the exchange of data/

Error checking

Data checking a

Acknowledgemetn

Works at laeyer 4 of the oci MODEL.

tcp ensure reliable transmission of data by breaking down larger messages into smaller packets.

TCP == 3 WAY HANDSHAKE

SYN > syn ack > ack

Error checking and flow control.

Employs flow control

Windowing: Allows the reciver to specify the amount of data it can handle at a time.

Port a numerical identifier in TCP/IP and other network protocols that helps distinguish between differnet services or applications.

Source and Destination IP

Source and Destionation Ports.

Ports are important in the communiation process because these ports allow for multiple network applications.

🔁 TCP – Transmission Control Protocol (Layer 4)

A fundamental protocol of the Internet Protocol Suite

Ensures reliable, ordered, and error-checked delivery of data between devices.

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✅ Key Features of TCP

| Feature | Description | | --- | --- | | Connection-oriented | Establishes a session using 3-way handshake | | Reliable | Guarantees delivery, retransmits lost packets | | Sequencing | Ensures packets arrive in correct order | | Acknowledgments | Confirms receipt of data | | Flow Control | Prevents sender from overwhelming the receiver | | Error Checking | Uses checksums to verify data integrity |

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🤝 TCP 3-Way Handshake

pgsql
CopyEdit
Client                           Server
  | ----------- SYN ---------->  |
  | <-------- SYN-ACK ---------  |
  | ----------- ACK ----------> |
  ✅ Connection Established

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🔳 Windowing (Flow Control Mechanism)

• Receiver tells sender how much data it can handle
• Helps prevent congestion or dropped packets
• TCP dynamically adjusts the window size for efficiency

🧠 Bigger window = more data at once

Smaller window = slower, more reliable transfer

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🔢 Ports: Identifiers for Network Services

• Numerical values used to distinguish between different apps/services
• Work with IP addresses to complete connections

| Element | Example | | --- | --- | | Source IP | 192.168.1.10 | | Destination IP | 10.0.0.5 | | Source Port | 49512 (ephemeral) | | Destination Port | 443 (HTTPS) |

🔑 Ports enable multiple network apps to run at once on the same device

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🧠 Memory Aid

TCP = "Total Care Protocol" → Reliable, caring, confirms delivery

Ports = App Doors → Each port = entry for a different network service

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⚡ Rapid Review Questions

1. What layer does TCP operate on?

   → Layer 4 (Transport)

2. What’s the purpose of the TCP 3-way handshake?

   → To establish a reliable connection

3. How does TCP ensure reliable transmission?

   → Error checking, sequencing, acknowledgments, and flow control

4. Why are ports important in TCP/IP?

   → They direct traffic to the correct application or service