Keith Moore wrote:
It should say that the IETF shamefully abandoned its own protocol,
despite it being valuable and providing features that don't exist > in any of the supposed protocols IETF replaced it with.
The essential advantage of ftp over other protocols is that
it support an end system type of "controller", in addition to
"sender" and "receiver", as is documented in rfc765 that:
data connection
A simplex connection over which data is transferred, in a
specified mode and type. The data transferred may be a part of
a file, an entire file or a number of files. The path may be
between a server-DTP and a user-DTP, or between two
server-DTPs.
which is similar to what we were and still are doing to copy
video contents between two recorders by an IR remote controller.
In general, "transfer" protocol needs three kinds of ends and
both PASV and PORT commands are essentially necessary for ftp.
Other protocols are silently assuming controller=sender or
controller=receiver, which may not be a problem for http but,
with an example above, it can be said that rtsp, for example,
is poorly designed.
Masataka Ohta
