Telnet operates at the application layer of the OSI model, specifically layer 7. This means it's responsible for providing a user interface to interact with remote systems. It doesn't directly manage network connections or data transmission – those lower-level tasks are handled by layers below it. While Telnet uses TCP (Transmission Control Protocol) for reliable data transfer, TCP resides at the transport layer (layer 4), and Telnet itself is built on top of this.
Several sources confirm this:
- Wirex Systems: Clearly states that "TELNET is an application-layer protocol, meaning that it is used on the application layer of the OSI (Open Systems Interconnection) model." https://wirexsystems.com/resource/protocols/telnet/
- Quora: Multiple Quora threads confirm Telnet's operation at OSI Layer 7, the Application Layer. https://www.quora.com/Which-layer-of-the-OSI-model-does-Telnet-operate-at https://www.quora.com/What-layer-is-Telnet
- Wikipedia: Reinforces Telnet's role as a client/server application protocol providing virtual terminal access. https://en.wikipedia.org/wiki/Telnet
Therefore, despite utilizing lower layers for functions like connection establishment and data transmission, Telnet's core functionality resides at the application layer. It's crucial to understand this distinction to grasp its role within the network stack.
