Just curious on learning about protocols. I know that TELNET is connection oriented protocol and IP is connectionless protocol. What does it imply when the networking blogs and resources say that "Telnet runs over IP"?

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    Can you please give more information where you read that ? telnet run over TCP which is run over IP.
    – Mr.lock
    Feb 26 '17 at 10:29

Telnet belongs to the OSI layer 7 (application layer) and IP belongs to the OSI layer 3 (network layer). At the network layer, the protocol is indeed connectionless, and at the application layer, it is indeed connection-oriented.

What solves this impedance mismatch, then? It is TCP. TCP works at OSI layer 4 (transport layer), and provides a reliable connection-oriented infrastructure on top of a connectionless network.

So, telnet doesn't directly run on top of IP. There is TCP inbetween. But, it is not incorrect to say that telnet runs on top of IP, as the OSI layer 7 protocol indirectly works on top of the OSI layer 3 protocol, being a higher-layer protocol.


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