TCP/IP
Click on the red underlined text to get to the source
... used in or by the Internet, whether or not they are part of the
TCP/IP protocol suite. In the case of protocols developed and/or
standardized by non-Internet organizations, however, the Internet
Standards Process ...
... ICMP must be implemented by all Internet systems using the
TCP/IP Protocol Suite.
(b) Recommended: Implementation of the referenced TS ...
... An Internet application used to interactively select and
retrieve files in a TCP/IP network. ...