What is the Transport Layer?

The Transport Layer is layer four of the OSI model.

The Transport Layer resides above the Network Layer and below the Session Layer.

The Transport Layer is responsible for delivering messages between networked hosts.

As part of this, the Transport Layer is also responsible for fragmentation and reassembly.

In addition, some Transport Layer protocols also provide services to manage flow control and end-to-end error recovery.
Transport Layer Standards

Standards which operate at the Transport Layer include: TCP and UDP.