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A bit of UDP history by its creator [1]: Actually, UDP was "un-designed" by me and others.By this I mean that
UDP was the final expression of a process that today we would call
"factoring" an overcomplex design. Originally, the ARPANET end-to-end
protocol NCP was a "kitchen sink" oriented toward providing remote
teletype-centric access using the "telnet" protocol and the "FTP"
protocol to remote machines over a packet network.
A group of us, interested in a mix of real-time telephony, local area
networks, distributed operating systems, and communications security,
argued for several years for a datagram based network, rather than a
virtual circuit based network. The group involved me, John Schoch and
Yogen Dalal of Xerox PARC, Danny Cohen of ISI (now at Caltech, I think),
and Steve Crocker, with Jon Postel as a supporter, and Vint Cerf and Bob
Kahn as neutral referees.
UDP was actually "designed" in 30 minutes on a blackboard when we decided
pull the original TCP protocol apart into TCP and IP, and created UDP on
top of IP as an alternative for multiplexing and demultiplexing IP
datagrams inside a host among the various host processes or tasks. But it
was a placeholder that enabled all the non-virtual-circuit protocols since
then to be invented, including encapsulation, RTP, DNS, ..., without having
to negotiate for permission either to define a new protocol or to extend
TCP by adding "features".
[1] "udp and me" http://www.reed.com/blog-dpr/?page_id=6 |