An ISP is currently drafting and compiling a Service Level Agreement that states there should only be 5.26 minutes of downtime per year, 25.9 seconds per month, and 6.05 seconds per week. Which of…

99.9% (three nines) permits approximately 8.76 hours of downtime per year, which far exceeds the 5.26-minute annual limit stated in the SLA.

99.99% (four nines) allows approximately 52.56 minutes of downtime per year, which is still much greater than the 5.26-minute target specified.

99.999% uptime, known as 'five nines,' is calculated by taking 0.001% of total time in each period - 0.00001 x 525,600 minutes/year equals approximately 5.26 minutes of allowable downtime per year. This is a well-established industry benchmark for high-availability SLAs. The monthly and weekly figures provided in the question align precisely with the five-nines calculation.

99.9999% (six nines) allows only about 31.5 seconds of downtime per year, which is more restrictive than the SLA metrics given and does not match the stated values.