The Transport Layer, also known as Layer 4, is responsible for providing reliable data transfer between nodes. This layer ensures that data is delivered efficiently and accurately, using protocols such as:

1. TCP (Transmission Control Protocol)

2. UDP (User Datagram Protocol)

3. SCTP (Stream Control Transmission Protocol)

The Transport Layer provides:

1. Connection-oriented or connectionless communication

2. Segmentation and reassembly of data

3. Error detection and correction

4. Flow control and congestion avoidance

5. Multiplexing and demultiplexing

TCP is a connection-oriented protocol that ensures reliable data transfer, while UDP is a connectionless protocol that prioritizes speed over reliability.

In the context of blockchain, the Transport Layer is responsible for ensuring that data, such as transactions and blocks, is transferred reliably and efficiently between nodes in the network. This layer plays a critical role in maintaining the integrity and consistency of the blockchain, and enabling nodes to communicate and validate data in a decentralized manner.