[net.lan] UDP protocol

allen@gitpyr.UUCP (P. Allen Jensen) (05/20/86)

Can someone explain to me what the differences are between UDP and
TCP ?  I understand that both are OSI level 4 protocols and both
run over the IP protocol.
-- 
        "It's quite easy, if you don't know how.
         That's the important bit.  Be not at all
         sure how you're doing it."
                                      -Arthur Dent


P. Allen Jensen
Manager, Systems Division
GTICES Systems Laboratory
Department of Civil Engineering
Georgia Insitute of Technology
Atlanta Georgia, 30332-0355
...!{akgua,allegra,amd,hplabs,ihnp4,masscomp,ut-ngp}!gatech!gitpyr!allen

ed@mtxinu.UUCP (Ed Gould) (05/22/86)

>Can someone explain to me what the differences are between UDP and
>TCP ?  I understand that both are OSI level 4 protocols and both
>run over the IP protocol.

UDP (``User Datagram Protocol'') is an unreliable datagram protocol.
It is connectionless, meaning that there is little overhead sending
a datagram.  ``Unreliable'' means that the sender has no way to know,
other than by cooperation of the reciever, if the datagram was
received.

TCP (``Transmission Control Protocol'') is a two-way, connected,
byte-stream protocol.  The protocol ensures that data is delivered
exactly once and in the correct order. or an error indication is
returned to the sender.

Both are built on top of IP (``Internet Protocol'') which deals with
issues like packet fragmentation (if the packet sent by TCP or UDP
is larger than the lower-level transport mechanism will handle) and
reassembly, addressing, and internetwork routing.

More details of these, and countless other protocols, can be found in
the appropriate RFCs (``Requests for Comment''), whose numbers I
don't have handy.

-- 
Ed Gould                    mt Xinu, 2910 Seventh St., Berkeley, CA  94710  USA
{ucbvax,decvax}!mtxinu!ed   +1 415 644 0146

"A man of quality is not threatened by a woman of equality."

cline@dartvax.UUCP (Greg Cline) (05/24/86)

In article <1807@gitpyr.UUCP> allen@gitpyr.UUCP writes:
>Can someone explain to me what the differences are between UDP and
>TCP ?  I understand that both are OSI level 4 protocols and both
>run over the IP protocol.

Briefly:
  
	The User Datagram Protocol (UDP) enables application programs
	to send messages to other programs.
  
	The Transmission Control Program (TCP) supports the basic
	data transfer, connection, data reliability, flow control,
	multiplexing, precedence and security functions.

Greg Cline, Dartmouth Graduate CIS 
PHONE:	 (1 603 646 3173)
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