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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Cost per prefix [was: request for help w/ ATT and terminology]
On Jan 20, 2008 9:46 PM, Patrick W. Gilmore <[email protected]> wrote: > > On Jan 20, 2008, at 8:46 PM, William Herrin wrote: > > > So at this point, the part of my analysis you still dispute is where I > > claimed that 75% of the $40k cost of an entry-level DFZ router was > > attributable to its ability to carry the needed prefix count. > > As I said before, your calculation is in error. I very clearly > explained why, but you threw out my explanation below. Patrick, Just to clarify, your "explanation" (which I've clipped again) claims an error in the source numbers, not an error in the calculation. Essentially, you've said that when I determined the percentage of an entry level DFZ router's cost attributable to the prefix count I chose as my point of comparison a piece of equipment that is not otherwise functionally equivalent for the DFZ router task. Because an equivalent piece of equipment would be more expensive, the percentage I found to be attributable to carrying and using the prefixes was too high. I disagree, but I acknowledge that you've offered reasonable support for the claim that 75% is not the correct percentage of the router's cost attributable to the DFZ prefix count. So, run with it. Take the analysis you just did and come up with a justified estimate of the percentage of the cost of a representative DFZ router which is attributable to its need to carry a full BGP table. If you think 75% is too high, lets talk about the number you think is correct and why. Perhaps you feel that only the cost of the pfc3bxl and msfc3 daughterboards should be attributable to the prefix count? Whatever. Pick your numbers and justify them as I have. Then lets plug your number in to the formula and see what we get. > Apparently I > assumed you had knowledge you did not. Please forgive me for not > assuming you were ignorant. I shall not repeat my mistake. Or, you could just respond with another ad-hominem attack. It won't advance anyone's understanding of the cost of carrying prefixes in the DFZ, but it might make you feel superior. > I'm certain there are networks who would (do?) use 3750s if the v4 > table were the size of the v6 table. But they tend to be smaller > networks, with few or no BGP customers, and not much traffic. No > 'tier one' network would, and most networks their size would not. > Most networks half their size would not. I don't believe that a tier 1's choice of DFZ routers is representative of the average DFZ router. Their requirements are much higher than the norm. If you'd like to argue the opposite position, I'll be very interested to see what numbers you propose for the representative router cost and the percentage attributable to handling the prefix count. > > For cost analysis purposes, you need only consider a true/false > > condition here: > > The device supports the required prefix count. > > The device does not support the required prefix count. > > Would that the world were so simple. In cost analysis as in software development, all complex problems reduce to a sequence of simple steps. Regards, Bill Herrin -- William D. Herrin [email protected] [email protected] 3005 Crane Dr. Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
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