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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: SONET ring questions
At 05:35 PM 10/15/98 -0700, Tony Li wrote: >[email protected] (Peter Polasek) writes: > >> This interface is extremely mission critical to the point >> that a 99.9% uptime will not be acceptable. I have the following >> questions: >> >> 1) Bell Atlantic assures us that, because of the redundancy, we can >> expect 100% uptime from the OC-12. I would like feedback as to >> whether this is a realistic portrayal of the SONET environment. > > >How many significant digits do you consider acceptable? Even in an ideal >APS environment, link failure detection and protection switching does take >finite time. You might get 99.999% uptime, but probably not 99.9999999%. > >Methinks that you've been subjected to Marketing. ;-) For total system uptime 90.0% (one nine or less) Desktop systems. 99.0% (two nines) Intermediate business systems 99.9% (three nines) Most business data systems and workgroup servers 99.99% (four nines) High-end business systems and your friendly neighborhood telco 99.999% (five nines) Bank Data Centers and Telco Data Centers, some ISPs 99.9999% (six nines) Only God and Norad live here. 99.99999% (seven nines) Even God doesn't have pockets this deep. There is a matching exponential cost increment with each step. ___________________________________________________ Roeland M.J. Meyer, ISOC (InterNIC RM993) e-mail: <mailto:[email protected]>[email protected] Internet phone: hawk.mhsc.com Personal web pages: <http://www.mhsc.com/~rmeyer>www.mhsc.com/~rmeyer Company web-site: <http://www.mhsc.com/>www.mhsc.com/ ___________________________________________ I bet the human brain is a kludge. -- Marvin Minsky
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