This is the fifth layer of the OSI and is part of the upper layer. In the presentation layer, data is organized into a standard format. As a result, it becomes necessary for a session to be established between the two hosts, the sender and the receiver. The session layer allows for users on separate machines to start sessions. So, such sessions as communication are established, managed and terminated at the session layer. The communication sessions have requests and responses for services that take place between the various applications that are located in various network devices. Consequently, the layer is concerned with the setting up, the organization and termination of the conversations and dialogs that may occur between the applications on different ends. The layer focuses on the management of sessions and connections.
It is in the session layer where the protocols that direct the service requests and responses are realized. Session layer executions include the Zone Information Protocol abbreviated as ZIP, the Apple Talk protocol that is used for coordinating the binding of the name process, the Session Control Protocol (SCP) and the DECnet Phase IV session layer protocol. The session layer helps in the tracking of information received in a certain end from another. The session layer performs certain functions. First, it allows for the virtual linking of applications. Secondly, it is indispensable in data flow harmonization. Third, it assists in dialog unit construction. The session layer also used in instances, where the recognition of data has been received, is necessary. Concurrently, it is through the session layer that data is retransmitted whenever it may not be received by a device as intended.
The layer can then be said to be concerned with the launch and the end of network connections. The Remote Procedure Call (RCP) functions and the portion of the SQL concerned with login in, are to be found in the session layer. Once a conversation is complete in the session layer, the data is then transferred to the presentation layer. It is important to note that this session layer has more in common with the application layer than the physical layer. This is because of the simple fact that it is set up in applications and involves the use of software rather than hardware. For instance, when a user runs several applications on their network, it would be correct to state that sessions are established among the different applications.
