mcb@LLL-TIS-B.ARPA (Michael C. Berch) (12/26/86)
Will Martin writes: > [. . .] However, as I > understand the tarriffs and how the long-line vendors sell their > circuits to users, there is little, if anything, that a buyer could do > to prevent the vendor from changing the physical circuits "behind" the > logical or virtual circuit you are buying and eliminating physical > redundancy that the customer thought he had. That is, you could design a > network, and buy circuits, with actual physical redundancy for your own > protection, but the telco could at some future date "streamline" its > facilities and put your two originally-separate circuits on the same new > physical link, without your ever even knowing about it or having any > recourse or means to protest this action. Tariffs notwithstanding, I think organizations requiring physical redundancy should state the requirement in Requests for Proposal and Requests for Quotations (RFPs, RFQs). A short sentence could require that the circuits ordered be "at all times" maintained in separate conduits, routed through separate trunks, routed through different switches, carried by different transport technologies (e.g., copper, fiber, satcom), or whatever the desired stringency of the physical redundancy may be, and with whatever exceptions (e.g., circuits permitted to be co-routed within customer's premises, or between premises and CO) you can live with. Obviously, this will be expensive. Michael C. Berch ARPA: mcb@lll-tis-b.arpa UUCP: ...!lll-lcc!styx!mcb ...!lll-crg!styx!mcb ...!ihnp4!styx!mcb