On Wed, 25 Feb 2004, Bora Akyol wrote:
It needs to be as reliable as the services that depend on it.
E.g. if bank A is using the Internet exclusively without leased line back up to run its ATMs, or to interface with its customers, then it needs to be VERY reliable.
That's not very reliable. On a "normal" day, 95% of the cash machines are working nationwide. Telephones, E911, hospitals, nuclear power plants have a variety of "normal" failures all the time. Humans are traditionally very bad at understanding risk.
As more and more critical services/infrastructure moves to the IP/MPLS, the expectations in terms of reliability go up every year. The real questions are:
* How much are the customer's willing to pay for it? * What kind of reporting/management infrastructure we have to enforce/monitor the reliability commitment in the SLA?
Unfortunately, both of those are marketing issues and have very little to do with actual reliability. One very well-known ISP had a "premium" Internet service that only cost 30% more than its standard Internet service with a 100% SLA. What you received was the same service with an insurance policy. If the service met the SLA you paid 30% more, if it didn't you only paid the standard price. Does buying travel insurance change the risk of the plane crashing?