0002293637@mcimail.com (Krislyn Companies) (03/06/91)
I need some information on the zone tables that long distance carriers use. How, for example, is zone 2 from Chicago determined? By area codes? Or something else? Are the zone tables for all of the carriers (AT&T, MCI, Sprint, for example) exactly the same? If they are in some type of database, is it possible to obtain it? Any idea how big it is (if it exists)? Thanks, Paul Wilczynski
K_MULLHOLAND@unhh.unh.edu (KATH MULLHOLAND) (03/09/91)
Paul Wilczynski asked for information about Long Distance zones. Each carrier, and sometime each carrier's given product, has their own way of calculating zones. Some use mileage, some use area code, and some say they use area code and really use mileage. When calculating our least cost routing, I made up a map of the discrepancies that existed at that time between Sprint, AT&T and MCI. This is only valid from New Hampshire, of course, but they varied on seventeen area codes. Insist on good maps from your vendor, and ask pointed questions of your vendor about whether the map is: 1) for the product you are buying (One company offers different band definitions for switched access and for direct access) 2) just an approximation or an accurate picture of how you will be charged 3) accurate for your calling area. In Chicago, I wouldn't expect this to be a problem, but in NH we often get maps valid for Boston, and our calling area is different. Once you have a map, make your own and mark the discrepancies between vendors. I have also used a compass to put mileage bands on my maps. The biggest discrepancy I noticed between the vendors was in Band 1. AT&T splits the other vendors' Band one into two bands (one and two !!) So later bands, to be compared in price, are off by one. In general, the other discrepancies were all on the more distant bands. AT&T generally was the odd vendor out, but occasionally MCI and Sprint differed on area codes in states with more than one LATA. More information -- my Sprint representative called and I asked him for clarification on the area code/mileage question. Sprint designates mileage bands, but when a band crosses through an area code, they movethe entire area code to the lower band. (They bill by area code.) MCI and AT&T, according to the same rep, bill by mileage, down to the NPA NXX level, puching NXXs into the lower band when they are separated by the mielage band. This accounts for some, but by no means all of the discrepancies I noted earlier. I'd be happy to discuss this further, either off-line or on the net. Kath Mullholand UNH Durham, NH.