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It occurs to me that a bare fiber could actually be (randomly) hung across treetops, roofs, power lines, and various other structures, over a many-block distance in suburban areas. Such a fiber wouldn't be

At 05:19 PM 7/23/96 -0400, Rabid Wombat wrote: protected

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very well, but it would probably last a few months. It would also be exceedingly hard to find its terminations, and tracing it would be a real pain. (It probably wouldn't be visible against a bright sky more than a meter or two away.)

It also would have little structural integrity - if you attached it to trees, which sway in the wind, you'd have a broken fiber in a short time. (The fiber doesn't even need to break, per se; microscopic cracking, usually at the cladding, will ruin your fiber) (bird strikes would also be a big problem, mostly for the bird)

But how long? I don't doubt that the effects you describe will occur, but I'm only talking about a _semi_-permanent installation. My guesstimate (months) was based on the idea that the fiber would be short (say, less than a kilometer)enough so that even accelerated loss (microcracking) wouldn't appreciably degrade the transmission. Also, I'm assuming that the fiber would be hung with enough slack so that swaying/growing trees wouldn't stretch the fiber appreciably.

ob crypto/privacy: Anybody have a good idea for detecting a tap on exterior fiber? I'd expect an attacker to have to interupt connectivity, terminate both ends of a break, and insert an active device. Thoughts?

They can tap a fiber by bending it over a small radius, which causes leakage around the OD without appreciably interrupting the signal. Changes are pretty good that this would b e the technology used. Jim Bell jimbell@pacifier.com