Session Layer – Layer 5
This layer is responsible for the establishment of connection, maintenance of sessions, and authentication, and also ensures security.
Functions of the Session Layer
- Session establishment, maintenance, and termination: The layer allows the two processes to establish, use, and terminate a connection.
- Synchronization: This layer allows a process to add checkpoints that are considered synchronization points in the data. These synchronization points help to identify the error so that the data is re-synchronized properly, and ends of the messages are not cut prematurely and data loss is avoided.
- Dialog Controller: The session layer allows two systems to start communication with each other in half-duplex or full-duplex.
Note:
- All the below 3 layers(including Session Layer) are integrated as a single layer in the TCP/IP model as the “Application Layer”.
- Implementation of these 3 layers is done by the network application itself. These are also known as Upper Layers or Software Layers.
- Device or Protocol Use : NetBIOS, PPTP.
For example:-
Let us consider a scenario where a user wants to send a message through some Messenger application running in their browser. The “Messenger” here acts as the application layer which provides the user with an interface to create the data. This message or so-called Data is compressed, optionally encrypted (if the data is sensitive), and converted into bits (0’s and 1’s) so that it can be transmitted.
Communication in Session Layer
What is OSI Model? – Layers of OSI Model
OSI stands for Open Systems Interconnection, where open stands to say non-proprietary. It is a 7-layer architecture with each layer having specific functionality to perform. All these 7 layers work collaboratively to transmit the data from one person to another across the globe. The OSI reference model was developed by ISO – ‘International Organization for Standardization‘, in the year 1984.
The OSI model provides a theoretical foundation for understanding network communication. However, it is usually not directly implemented in its entirety in real-world networking hardware or software. Instead, specific protocols and technologies are often designed based on the principles outlined in the OSI model to facilitate efficient data transmission and networking operations.
Prerequisite: Basics of Computer Networking
- What is OSI Model?
- What are the 7 layers of the OSI Model?
- Physical Layer – Layer 1
- Data Link Layer (DLL) – Layer 2
- Network Layer – Layer 3
- Transport Layer – Layer 4
- Session Layer – Layer 5
- Presentation Layer – Layer 6
- Application Layer – Layer 7
- What is the Flow of Data in OSI Model?
- Advantages of OSI Model
- OSI Model in a Nutshell
- OSI vs TCP/IP Model