"The Session Layer is responsible for establishing, managing, maintaining, and terminating communication sessions between applications."

Learning Objectives

By the end of this chapter, you should be able to:

• Explain the purpose of the Session Layer in the OSI model.
• Understand what a session is.
• Describe how sessions are established, maintained, and terminated.
• Explain session synchronization and checkpoints.
• Understand authentication during session establishment.
• Differentiate between stateful and stateless communication.
• Explain Remote Procedure Calls (RPCs).
• Understand where APIs fit within modern networking.
• Connect Session Layer concepts to AWS, Docker, Kubernetes, and modern DevOps environments.
• Answer common DevOps interview questions related to sessions.

Introduction

Imagine you call a friend on the phone.

The conversation follows a sequence:

1. You dial the number.
2. Your friend answers.