TCP and UDP

1. Protocol Type

• TCP (Transmission Control Protocol):
  Connection-oriented protocol. It establishes a reliable connection before data transfer.
• UDP (User Datagram Protocol):
  Connectionless protocol. No prior connection setup; data is sent directly.

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2. Reliability

• TCP:
  Reliable – ensures data delivery, error checking, and retransmission if packets are lost.
• UDP:
  Unreliable – no guarantee of delivery, no retransmission, minimal error checking.

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3. Speed

• TCP:
  Slower due to overhead of connection setup, acknowledgments, and error handling.
• UDP:
  Faster because it skips these steps; suitable for real-time applications.

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4. Use Cases

• TCP:
  Web browsing (HTTP/HTTPS), email (SMTP), file transfer (FTP), remote login (SSH).
• UDP:
  Streaming (video/audio), online gaming, VoIP, DNS queries.

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5. Packet Structure

• TCP:
  Larger header (20 bytes) – includes sequence numbers, acknowledgment, etc.
• UDP:
  Smaller header (8 bytes) – only source/destination ports, length, checksum.

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6. Error Handling

• TCP:
  Built-in mechanisms for error correction and retransmission.
• UDP:
  Minimal error detection (checksum), no correction.

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Summary:

• TCP = Reliable, slower, connection-oriented.
• UDP = Fast, lightweight, connectionless, best for real-time apps.

TCP vs UDP Comparison

Feature	TCP	UDP
Protocol Type	Connection-oriented	Connectionless
Reliability	Reliable (acknowledgments, retransmission)	Unreliable (no guarantee of delivery)
Speed	Slower (due to overhead)	Faster (minimal overhead)
Use Cases	Web browsing, email, file transfer	Streaming, gaming, VoIP
Packet Header	Larger (20 bytes)	Smaller (8 bytes)
Examples	HTTP/HTTPS, FTP, SMTP, SSH	DNS, Video Streaming, Zoom, Online Games