Session Layer
The Session Layer is Layer 5 of the OSI (Open Systems Interconnection) Model of computer networking. The Session Layer is directly after the Transport Layer and before the Presentation Layer, allowing it to interact with applications as well as network components. The Session Layer is responsible for opening, maintaining, and closing all sessions between multiple applications and/or devices. Because almost all network-related events involve the use of sessions, the Session Layer is used extremely often.
How The Session Layer Works
The Session Layer is responsible for opening, maintaining, and closing sessions between multiple applications and devices. A “session” is essentially a conversation between two applications or devices, consisting of requests and responses, and is used to share messages regarding how information is going to be handled. While the Session Layer is not responsible for actually transporting messages, it is responsible for contacting a remote location, delivering requests, and receiving responses. The Session Layer is also responsible for passing on any data that needs to be handled to the Transport Layer.
Applications
The Session Layer is an important component of the OSI Model and is used by most computers and applications on a daily basis. For example, when a user opens a web browser and visits a financial web site such as Paypal or an online bank account, the Session Layer is used to contact the server of that website and ask it how it will encrypt the user’s data. The server then responds with an answer and negotiates with the user’s computer on the best type of encryption to use and agree on the encryption keys. While this example is specifically targeted towards financial information and shows the necessity of the Session Layer for two devices or applications to communicate with one another, the Session Layer does essentially the same thing for every website the user accesses, especially when a username or password is required.
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- Presentation Layer
The presentation layer is one of seven layers of the OSI (Open Systems Interconnections) Model and is found between the application layer and the session layer. The presentation layer is commonly used for encryption and decryption as well as the conversion of file formats. The presentation layer is considered the last layer in which data [...]...
- Transport Layer
The transport layer is the fourth layer of the OSI Model and exists between the Session Layer and Network Layer. The transport layer is used to actually transfer data from one application to another and can be used to stream data from one device to another. The most popular transport layer, the Transmission Control Protocol, [...]...
- Application Layer
The application layer of a software is a protocol that is used for communication between a software and the network layers that it uses. The application layer allows a computer’s network to interpret requests made by the program and allows the program to interpret data from the network. Likewise, the application layer ensures that both [...]...
- Physical Layer
The Physical Layer is the lowest layer in the OSI (Open Systems Interconnection) Model of computer networking and is used to transfer electrical signals that represent data from one place to another. While the Physical Layer does not represent data itself, it does provide a means for that data to move. Essentially, the Physical Layer [...]...
- Data Link Layer
The Data Link Layer is layer two of the OSI model. It resides above the Physical Layer and below the Network Layer. The Data Link Layer is responsible for communications between adjacent network nodes. Hubs and switches operate at the Data Link Layer. The Data Link Layer is logically divided into two sub-layers: The Media [...]...