>The Long and Winding Road wrote: >> >> ""Steven A. Ridder"" wrote in message >> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >> > I always thought that the PSTN was based off of that fact >> that not all >> > phones would be calling at once, and if they did, then some >> would get >> > through while others wouldn't. >> >> CL: yes. true. however, decades ago the Bell folks knew and >> practiced the >> optimum manner in which to provision such that you or I or any >> other >> individual would experience dial tone almost all of the time. >> We know this >> through the Ehrlang calcualtions. > >Yes, but that's based on the assumption that not everyone will call at once. >It won't work in an emergency. It didn't in 1989, for example.
Emergency services and the like can obtain special numbers that are much more likely to be usable in a massive overload situation. Consult the National Communications System (www.ncs.gov). Essentially, the lines in question are preprovisioned with special rights and often a PIN; there are several types of service available. You have to establish need for these services, as part of critical national infrastructure, life-dependent local services, military support, etc. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=55640&t=55573 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
