On Wed, 16 Jul 1997, Ron Buchalski wrote: Sprint uses 4 ring sonet loops. Two backup and two active. This way there is total capacity availiable in the event of a fiber cut. The data just takes the reverse way around the loop on the backup path. I believe they should have all the loops completed by the end of the year. Tony
The key is to go with multiple suppliers who can guarantee diverse routes. Carriers lease capacity from each other in some cases, so Sprint and MCI can give you circuits in the same physical fiber.
Sprint and AT&T are implementing SONET protection switching which will reroute circuits around fiber cuts in 50ms. I don't know if they do it as a rule, or if you need to specify rerouting priority (and pay for it).
It's interesting to look at a carrier's fiber map and compare it to a railroad map. You'll see MANY similarities. Railroad rights of way are the easiest areas to install fiber.
-rb
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------------------------------------------------------------------------------ Tony Pardini Systems Engineer CompuNet, INC. tony@cmpu.net pgr 2145817737