Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!gatech!bloom-beacon!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!pasteur!ucbvax!orc.olivetti.COM!roode From: roode@orc.olivetti.COM (David Roode) Newsgroups: comp.protocols.tcp-ip Subject: Re: Linking LAN's via Public X.25 Message-ID: <8806050525.AA00175@orc.olivetti.com> Date: 5 Jun 88 05:25:19 GMT References: <04.JUN.1988.15:12:54.LAWS@RSRE> Sender: daemon@ucbvax.BERKELEY.EDU Organization: Olivetti Research Center, Menlo Park, CA Lines: 44 There's no question that X.25 packet switching is a service built on top of point-to-point data circuit (leased line) capability. The tariffs in the U.S treat this as a 'value added' service and prohibit the basic operating companies from competing in the national market. The Public Data Networks offering packet services have to pay the same leased line rates as an end-user, both for backbone circuits and for ties between their switch locations and customer premises. At the same time, the charges for leased line service are obviously much cheaper in the U.S. than they are elsewhere. (It calls for a judgement, but it seems likely that much in excess of costs is recovered in the charges for leased line service in Europe.) As a result, it may be illogical to 'blame' the U.S. Public Data Nets for their charges. European PTT's may subsidize their X.25 offerings. U.S. PDN's see reduced usage volume due to reasonable competition from leased lines. The main service a PDN provides is the sharing of data circuits. So, in the U.S. a smaller fraction of uses see an economic incentive to share costs by making use of a PDN. (It takes a smaller volume of usage to cost justify switching to a leased line in the U.S.) The operating efficiency of the U.S. PDN's may be the same or even higher than the European PTT's in providing PDN service. It appears the hierarchy in terms of increasing cost for a 2400 baud data flow is something like: leased lines at U.S. typical rates Public Data nets at European rates Public Data nets at U.S. rates leased lines at European rates For 300 baud data flow, it is something like: Public Data nets at European rates Public Data nets at U.S. rates leased lines at U.S. typical rates leased lines at European rates For 9600 baud data flow, sequence might be: -or- leased lines/ U.S. rates leased lines/ U.S. rates Public Data nets/ U.S. rates Public Data nets/ U.S. rates Public Data nets/ Europe rates leased lines/Europe rates leased lines/Europe rates Public Data nets/ Europe rates