TCP/IP Model Overview

Introduction

• Discussion about the TCP/IP model.
• Reference to the OSI model; suggested watching the OSI model video first.

Definition of TCP/IP Model

• Standardizes computer networking.
• Similar description to the OSI model.
• The TCP/IP model is widely used in practical applications.

Structure of TCP/IP Model

• Original Model: Four layers numbered from the bottom up:

  1. Application Layer
  2. Transport Layer
  3. Internet Layer
  4. Link Layer

• Updated Model: Five layers with modifications:

  1. Application Layer
  2. Transport Layer
  3. Network Layer (formerly Internet Layer)
  4. Data Link Layer (split from Link Layer)
  5. Physical Layer

Comparison with OSI Model

• OSI model consists of seven layers:
  • Application, Presentation, Session layers combined into one Application Layer in TCP/IP.
• Other layers align nicely with the OSI model.

Protocols and Devices at Each Layer

• Application Layer: Protocols include HTTP, FTP, SMTP.
• Transport Layer: Main protocols are TCP and UDP (port numbers added).
• Network Layer: Contains Internet Protocol (IP); routers operate here.
• Data Link Layer: Contains Ethernet; switches operate here.
• Physical Layer: Involves tangible components like cables and network interface cards.

Data Transmission Process

• Encapsulation: Each layer adds its own information during data transmission.
• Decapsulation: The process on the receiving end where data is unpacked.
  • Begins at the application data at layer 5, proceeding downwards.

Details of Encapsulation

1. Application Layer: Data (no additional information yet).
2. Transport Layer: Adds TCP header (source & destination port numbers, sequence numbers).
3. Network Layer: Adds IP header (source & destination IP addresses).
4. Data Link Layer: Adds header (source & destination MAC addresses) and trailer (error checking info).
5. Physical Layer: Data is transmitted physically.

Naming of Data at Each Stage

• Layer 5: Data.
• Transport Layer: Segment.
• Network Layer: Packet.
• Data Link Layer: Frame.

Receiving Data Process

• The receiving computer checks:
  1. Destination MAC address of the frame.
  2. Source and destination IP addresses in the packet.
  3. Transport information for further processing.
• Application data is sent to the appropriate receiving application.

Conclusion

• Overview of TCP/IP model covers key concepts from OSI model.
• Video part of a full CCNA course, link available in description.
• Encouragement to like, comment, and subscribe for feedback.