Transport Layer in Computer Networks

Introduction

• Welcome to Engineering Panda family.
• New chapter on the transport layer in computer networks.

Transport Layer Overview

• Layer Position:
  • Layer number 4 in both OSI and TCP/IP models.
  • OSI Model: 7 layers total, with transport layer as the 4th.
  • TCP/IP Model: Includes application layer followed by transport layer.

Functionality of Transport Layer

• The transport layer performs various functions including:
  • Segmentation:
    • Takes data from the station layer (in OSI) or application layer (in TCP/IP).
    • Segments large data into smaller chunks, called segments.
    • Each segment is assigned a sequence number and a port number.

Data Types

• Raw data can include:
  • MP3 files
  • Video files
  • Image files
  • Text data

Segmenting Data

• Segmentation involves:
  • Assigning sequence numbers to segments to maintain order.
  • Assigning port numbers to identify the process using the data.
  • Example:
    • Google Chrome has one process with a port number.
    • Skype has a different process with its own port number.

Key Functions of Transport Layer

1. Segmentation: Splitting data into smaller segments.
2. Flow Control:
   • Essential to prevent data overflow.
   • Example scenarios:
     • Transmitter sends data faster than the receiver can handle.
     • Receiver can request to increase/decrease speed.
3. Error Control:
   • Implemented using TCP and UDP protocols.
   • TCP is connection-oriented and includes flow and error control.
   • Error control example: Automatic Repeat Request (ARQ).
   • Receiver can request retransmission of corrupted frames.
4. Process-to-Process Communication:
   • Manages data flow between processes over the network.
   • Each process on the receiving end is assigned data based on port numbers.

Conclusion

• This lecture provided a brief overview of the transport layer functions.
• Future videos will cover TCP and UDP in detail.
• Viewers encouraged to share comments or questions.