On 1/17/07, Ben Scott <[EMAIL PROTECTED]> wrote:
To say nothing of the redundancies in conventional POTS design (which really is, in general, some of the most robust engineering I've ever seen in the public sector). (Emphisis POTS here -- anything more than -48 VDC talk battery and the whole story changes.) Redundant in-building power wiring, redundant battery banks, generator backup for the batteries, dedicated line for each and every subscriber (pair gain not withstanding), no electronics anywhere for outside plant, auto failover for trunk routing, etc. The infrastructure I've seen in most Internet provider systems can't hold a candle to it. Obviously, any system can still fail, but for the most part, *none* of this exists for Internet service -- especially home Internet service.
Sadly, I doubt there are many systems engineered as well as the POTS system. Bell labs did a study on the effect of lightening on buried lines even. Now, they just bury the lines and deal with the consequences. When I was at Genuity, I heard that the GTE phone switches in the basement of one of the towers on 9/11 *kept working* until the batteries went dead. Much of Manhatten's phone lines went through there. Can your network survive the collapse of a building on top of it? What other system is engineered for failure as well as the POTS stuff? Railroad signaling? Lunar Lander life support? Fighter aircraft?
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