Application protocols define the way in the TCP reliable service
can be used to achieve network-based computing. Because
applications can assume reliability, their protocols can be
relatively simple.
Most Internet application protocols use commands (and, in some
cases, responses) in a human-readable form. They normally also use
plain ASCII text (see later) where possible. This makes debugging
the protocols quite straightfoward in most cases.
Some application protocols include:
Telnet
provides remote login allowing a user to log into a remote
computer as though it was local. We examine Telnet in this
lecture.
SMTP
(Simple Mail Transfer Protocol) is the Internet electronic mail
delivery protocol. We look at electronic mail in the next
lecture.
FTP
(File Transfer Protocol) is used to copy files from one system
to another.
HTTP
(HyperText Transfer Protocol) is the protocol basis of the
World Wide Web.