Session Layer Protocols Explained

There is always a need for a theoretical model to explain the working of anything, and that is what Open System Interconnection (OSI) model does.

The purpose of the OSI model to visualize the communication process in networking. It is almost used in all internet network operations. We will have a look at the session layer protocols in this article.

OSI Model

It has seven Layers that are:

1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer

It works from top to bottom while receiving and bottom to top while sending the data. Each layer has different protocols based on its function and collectively all layers work for the transmission of data from one system to another.

What is a Session in Networking?

A session in networking is communication between sender and receiver or user and computer established temporarily to interchange the information. It is the most basic step of communication between devices.

This session does not work for a single device, there must be at least two devices for defining a session. The session can be explained in this way as well that the period between logged in and logged out time or total time of engaging in a single activity.

The data stores in temporary variables and cleared as you end the session. Session layer operation depends on the establishment of the session.

What is the Session Layer?

It is the fifth layer of the OSI model and operates after the transport layer.

The session layer establishes a connection called session, maintains, and authenticates it, and assures the security of the information/identity. Simply it manages the conversation of different devices and creates two endpoints. It also reconnects and creates another session if the session gets interrupted or dropped.

It is the session Layer’s responsibility to start and end a session, either it is simplex, half-duplex or full duplex. This Layer synchronizes the session streams while devices are communicating. Besides establishing a connection and synchronizing, the session layer also masks failures of upper layers like the transport layer.

What Does the Session Layer Do?

As explained in the above section that session layer setups sessions, based on this there are some functions of the Session layer.

Here is the list of what the session layer does:

• Session: It establishes, synchronizes, manages, and ends the session.
• Reconnecting: Reestablishes the session if disconnected.
• Endpoints: Session Layers creates endpoint of devices.
• Masking: It masks mistakes of upper layers.
• Way of Communication: Communication through the session layer can be a duplex, half-duplex or full-duplex and connect two devices.
• Multiple sessions: The session layer can also control multiple sessions or connections at a time.
• Shipping address: Add the address to which the data is to be sent.
• Security: It secures the user credentials, and only shares the limited user data.

Session Layer Devices

Every layer uses some devices to perform its tasks, so the devices used in the session layer are:

1. Gateway: It is a hardware device that allows the transmission of data from one network to another. It acts as a node for other networks considered as a node.
2. Data load Balancers: as the session layer manages the transfer of data in a session, so it used data load balancers to balance the traffic of data while transmitting it.
3. Firewalls: The different types of firewalls at the session layer are for protection.
4. Computers: The device for data transfers and the one that receives the data is a computer.

Session Layer Protocols Explained

A network protocol is a stream of commands that are followed to perform a certain task. SESSION Layer uses several protocols that are:

1. Layer 2 Forwarding Protocol

A tunneling protocol that itself does not provide direct encryption or confidentiality but tunneled with a protocol to provide security.

It is a point-to-point or serial line internet protocol virtual dial-up that provides authentication and Dial-in user service and quality of service. It is part of the Layer 2 tunneling protocol.

L2F works with the PPP and setups a connection between the client and the network when the client starts the process and is ended by NAS.

2. Remote procedure call protocol

Remote procedure call protocol works as a request-response protocol. A client starts an RPC by sending a request to a remote server, and as the remote server receives the response, it responds to the client message.

It is also called a subroutine call or function call. It helps in communication between two networks and workstations. RPC in session layer is to set up an end-to-end connection of sending and receiving responses.

3. Password authentication protocol

Password authentication protocol works based on password-based authentication. Like layer 2 forwarding protocol, it is also pointing to the point protocol used for validation.

PAP is compatible with almost all network operating systems. As mentioned, it is a password authentication protocol, but it is not the stronger one. It has lighter security against vulnerable attacks.

 Also, Checkout What is Single Factor Authentication?

4. Zone Information Protocol

The Zone information protocol is for the maintenance of the zones by providing names to the network. This protocol manages the nodes in zones and then names them.

It is basically for implementing the routers. ZIP is embedded in nodes for receiving the information from routers in collaboration with the Apple talk Transaction protocol.

5. Network Files System

A distributed file system protocol that allows users to access the file. Network File System is based on the open network computing remote procedure call system and works on requests for comments. Anyone can implement this protocol in his network.

Session Layer Examples

• Video Conferencing
• Streaming
• Logging in and out
• DNS
• NetBIOS
• LDAP

Summing Up

The session is simply the time for a particular task, and the session layer is the implementation of the session in different models. The session layer protocols are NFS, ZIP, PAP, RCAP, and more.

The session layer has many advantages including privacy, security, maintenance, and masking.

Also, Read What is a Network? Learn About Networking