TCP/IP (Re: VMS talking to UNIX)

[ron%brl-vgr at sri-unix.UUCP]

From:      Ron Natalie <ron at brl-vgr>

DECNet and TCP/IP are both different upper level protocols.  They both
handle a variety of network hardware.  TCP/IP just carries on a bit farther.
The Internet Protocol (IP) is a Department of Defense standard network
protocol that allows any two hosts on any network to talk to each other.
The Internet Community is composed of over 100 active nets which include
the ARPANET and MILNET.  Users on different networks communicate trans-
parently with each other do to magic in IP and computers called gateways.
TCP is the Transmission Control Protocol.  It essentially takes packets
and turns them in to reliable virtual circuits (like unix pipes between
machines).  On top of TCP there are Virtual Terminal (telnet), file
transfer, and Mail protocols.

All this means is sitting in my office, I can type "telnet UCLA-CCN"
and then start logging in to an IBM in California.  This goes through
a couple of local area nets here and accoss the MILNET to the ARPANET
to UCLA.  DECNet sort of does this provided you are using DEC machines
and DEC network hardware.  TCP/IP is available on all DEC machines and
nearly every operating system that will run on them, IBM's (both mainframes
and the PC), UNIVACs, Honeywells, and most anything that runs Unix (Gould,
Pyramid, Suns, and most of your smarter micros).  It allows use of the
ARPANet style BBN Packet Switches, Ethernets, and a who slew of more
exotic networking hardware.  In addition, zapping around the country
on a network that your tax dollars paid for is a little self satisfying
(do that on DECNET!).

I hope this helps.

-Ron