The Session Layer, also known as Layer 5, is responsible for establishing, maintaining, and terminating connections between nodes. This layer is responsible for:

1. Connection establishment and termination

2. Session management and coordination

3. Dialogue management and control

4. Synchronization and checkpointing

Protocols that operate at the Session Layer include:

1. NetBIOS (Network Basic Input/Output System)

2. SSH (Secure Shell)

3. SSL/TLS (Secure Sockets Layer/Transport Layer Security)

4. RPC (Remote Procedure Call)

5. NFS (Network File System)

The Session Layer manages the communication session between nodes, ensuring that data is exchanged in a logical and efficient manner. This layer is critical for enabling nodes to communicate with each other and exchange data in a structured and controlled way.

In the context of blockchain, the Session Layer is responsible for managing the communication sessions between nodes, ensuring that they can exchange data and validate transactions in a secure and efficient manner.

Some key functions of the Session Layer in blockchain include:

1. Node connection management

2. Session key exchange and management

3. Transaction validation and verification

4. Block synchronization and validation

5. Node communication and data exchange