Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ucbvax!CS.UCL.AC.UK!J.Crowcroft
From: J.Crowcroft@CS.UCL.AC.UK (Jon Crowcroft)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Reliable Datagram ??? Protocols
Message-ID: <9010231729.AA05292@ucbvax.Berkeley.EDU>
Date: 23 Oct 90 14:56:40 GMT
References: <12632005207.2.BILLW@mathom.cisco.com>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 25


the world used to divide into 
datagram & virtual circuit

it now cuts many ways -

connection oriented versus connectionless is on dimension, but
reliability is another orthogonal issue ... some people would assert
that using a 'first' datagram to establish buffer allocation for an
entry in a router's tables to decide on who gets packets dropped is 
connection oriented ... it's just not reliable...on the other hand,
asking for the right TOS may insure reliability, even though the
packet format is datagram...

so i dont agree with jon postel...however, "reliable internet" may be
an oxymoron:-)

but seriously, 'reliable virtual circuits' is an oxymoron if you've
ever tries using (I)PSS...calls get ripped out with disconnection
reasons like 'congestion' , which doesnt sound too dissimilar from
routers dropping packets (except you have to wait a while longer
before sending your next packet - or do you - well prob. not if you
are running slow start x.25, now there's an idea:-))

jon crowcroft