What is the difference between a tunnel, a VPN tunnel and an SSH tunnel? According to Wikipedia, "tunneling" is:
Tunneling typically contrasts with a layered protocol model such as those of OSI or TCP/IP. The delivery protocol usually (but not always) operates at a higher level in the model than does the payload protocol, or at the same level.
But that doesn't really mean much to me. So is a tunnel like HTTP being used to carry a TCP payload?
I guess all this "tunnel terminology" would make sense with a few practical (real-life) examples.