Cell Relay Archive

[George Marshall <george@marshalls.org>]

> Does anyone know which criteria should be used when to decide
> whether to use UTP5 or multimode fiber? When I understood
> the information I got so far correctly, UTP5 should only be used
> if distances are below 100m. In my case this will be definitly the
> case. We intend to cluster a few computers via an ATM switch
> (155MBit). Most of the computers will be stacked together
> (distances will be 1m at maximum) with a few computer having
> distances of about 30m to the switch.
> As to my knowledge now, I will buy the UTP5 variant. Are there
> any circumstances I should be aware of that might make MM Fiber
> an important alternative?

For local connections like your workstation application, ATM over UTP5
is more economical than fiber because the copper transceiver cost less
than the equivalent fiber modules.  Depending on your existing building
wiring, you may be able to run over the wire already in your walls,
perhaps saving some additional media costs.

Error rates for this copper environemt are low, so no real reason to use
fiber.
Note that just about every ATM LAN swithc will let you configure a mix
of copper and fiber interfaces, it's easy to add one or two fiber
interfaces as needed for trunks.

Only if you thought it likely that some of the workstations would soon
need to be moved over 100m away would you want to consider fiber.

George Marshall
--
george@marshalls.org [It's just me]