Transport Layer

What is the Transport Layer?

The Transport Layer is the fourth layer in the OSI reference model, which categorizes network protocols into the following seven layers:

1. Physical Layer: Defines the electrical and mechanical functions and specifications for data transmission.
2. Data Link Layer: Defines the functions and specifications of the physical communication channel and the data formats transmitted over it.
3. Network Layer: Handles the selection of communication paths and management of addresses to deliver data to the destination host (node).
4. Transport Layer: Ensures reliable and efficient delivery of data to the destination.
5. Session Layer: Defines functions and specifications for establishing and terminating virtual paths (sessions) between communication applications.
6. Presentation Layer: Defines functions and specifications for transforming the format of data exchanged during communication.
7. Application Layer: Defines functions and specifications for the exchange of application-level information.

The Transport Layer resides above the Network Layer (e.g., IP) in the protocol stack. While the Network Layer manages communication between hosts specified by IP addresses, the Transport Layer is responsible for managing communication between ports on the hosts. Key protocols in the Transport Layer include UDP (User Datagram Protocol) and TCP (Transmission Control Protocol).