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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: value of co-location
On Fri, 19 Jan 1996, Jim Forster wrote: > > Not using either of the last two fast packet services, in particular, will > > also yield 30% more useful bandwidth from a T3 circuit. This all by itself > > may make up for the co-location costs and the cost of a router. > > What's the average packet size now? I think the overhead on DS-3 ATM/SMDS > is worse than on OC-3, if I recall correctly, because the DS-3 PLCP is so > wasteful as well. Someone should redo these calculations more accurately. With PLCP, maximum bit rate available for ATM cells = 53 cells * 12 rows * 8bits / 125us = 40.704 mpbs. So, 40.704 * 48/53 = 36.864 mpbs = data rate. Now if you use AAL5, then it's another 2 bytes for SAR, and 2 bytes for CS, so, 40.704 * (48-4)/53 = 33.792 mpbs. Now, that's the theorectical maximum, and you go down from there. -dorian ______________________________________________________________________________ Dorian Kim Email: [email protected] 2901 Hubbard Drive Network Engineer Phone: (313)998-6976 Ann Arbor MI 48105 CICNet Network Systems Fax: (313)998-6105 http://www.cic.net/~dorian
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