Don has it right. Using an inTERnet connection is not acceptable for this application. Only a closed, private network (inTRAnet) is even barely acceptable, and then there is still the problem of what is called "backhoe fade." Pretty self explanatory.
Jed Barton wrote: > voip can be very relyable. > You just have to set it up right. > > On Behalf Of Bill Smith > > > VoIP is used daily and has been for over five years for mission-critical > applications such major electric and gas utilities and public safety. VoIP > isn't the problem, it's the transport medium. > > Bill > > --- On Mon, 1/4/10, Don E. Wisdom <[email protected]> wrote: > > > try again. I am a network engineer and I can tell you all it takes > is one mistake or routing loop extended power failure etc and your down for > a while. Anyone who would even think about doing this over the internet > needs their head checked. Ask yourself this question... If your power goes > out at home & you have comcast digital voice (that goes over the cable > modem) and someone robs your house.. What does your alarm do? Nothing! it > cant call out because the power is out. VoIP is not a technology that > anyone should be relying on for LIFE SAFETY things. > > the standard SLA on a T1 connection is 4 hours. (and it should be > since it costs $4-500/month) realistically they aren't going to fix it until > they're 4 hours are up. Home/business DSL connections typically have no SLA > or it isn't worth the toilet paper it is printed upon. Its been proven > multiple times in the last year (san francisco fiber cut, deep sea fiber > cuts, turkey stealing youtube's ip space etc) that the internet is not 190% > reliable. You have to remember that you may have a competent admin but you > are just as vulnerable if someone else does not have one. > One other thing.. 99.99% of VoIP applications use UDP which is a > connectionless protocol. meaning that the side sending it has no clue if it > got there. Simply put it either gets there or doesn't and you have no idea > which. > > This is a bad bad bad bad bad bad bad bad bad idea. No insurance > company in their right mind will touch this. I'd heard that the NFPA is > also looking at banning VoIP's use for fire alarm systems. > > --Don
