OSI Model's Lower Layer: Session Management
In the world of networking, the Session Layer, situated at Layer 5 of the OSI model, plays a crucial role in managing and controlling communication sessions between applications. This layer is responsible for ensuring that data is delivered reliably while also managing dialogue, synchronization, and recovery from interruptions during sessions.
One of the key devices operating at the Session Layer is the gateway or session-aware router/firewall. These network devices handle session establishment, maintenance, and termination between two communicating systems. They also monitor and regulate ongoing sessions, acting as a guardian for the network.
Another example of a device that operates at the Session Layer is the remote login server, such as a Telnet server. These servers manage application sessions for remote access, allowing users to connect and interact with a remote system as if they were physically present.
In the realm of Voice over Internet Protocol (VoIP), Session Border Controllers (SBCs) are essential. These devices control call sessions between users, ensuring smooth communication and managing the flow of data.
Modern networks, particularly those in the Internet of Things (IoT), often employ protocols like Message Queue Telemetry Transport (MQTT). These protocols are used to manage sessions between many low-power devices, facilitating efficient data transmission.
The Session Layer also employs techniques like checkpoints to allow data recovery in case of communication failure. This feature ensures that even in the event of an interruption, the session can be resumed without losing crucial data.
Additionally, the Session Layer is home to the Remote Procedure Call Protocol (RPCP). This protocol is used when a computer program causes a procedure (or a sub-routine) to execute in a different address space without the programmer explicitly coding the details for the remote interaction.
It's worth noting that the AppleTalk Data Stream Protocol (ADSP), developed by Apple Inc. in 1985, operates at the Session Layer. ADSP includes features for self-configuration and has two protocols: AppleTalk Address Resolution Protocol (AARP) and Name Binding Protocol (NBP).
Lastly, the Point-to-Point Tunneling Protocol (PPTP) provides a method for implementing virtual private networks, operating at a higher layer but with some overlap in functionality with the Session Layer.
In conclusion, while the Session Layer may not be as physically evident as other OSI layers, its role in managing communication sessions is indispensable. From gateways and session-aware routers/firewalls to remote login servers and IoT devices using session protocols like MQTT, the Session Layer ensures that data is delivered reliably and that communication sessions run smoothly.
- The Session Layer, where protocols like Remote Procedure Call Protocol (RPCP) are found, is instrumental in executing procedures in a different address space without explicit remote interaction coding, a crucial aspect in data-and-cloud-computing.
- In data-and-cloud-computing, Session Border Controllers (SBCs) are indispensable in Voice over Internet Protocol (VoIP) networks, managing call sessions between users and ensuring smooth communication across operating systems.
