ABSTRACT
MTBF + MTTR (9.8)
where MTTR is Mean Time To Repair.
ICMP pings are the easiest to use and report on measuring availability. The following equation shows the relevant formula:
Avail = (Total# of PINGs received)
(Total# of PINGs sent) (9.9)
Availability Statistics
Availability can be defined as the probability that a product or service will operate when needed. In networks, this can be defined as the average fraction of connection time that the product or service is expected to be in operating condition. For a network that can have partial as well as total system outages, availability is typically expressed as network
Availability = 1− total connection timein−service
(9.10)
The availability of objects or services can be an important source to evaluate the reliability of objects.
