Glossary

Availability

Link availability is typically expressed as a percentage availability measured over one year. 5.3 minutes of outage per year equates to 99.999% availability. 53 minutes of outage per year is equivalent to 99.99% availability and so on. Note that a failure to meet availability levels may not actually mean that data is no longer delivered by the link, but rather indicates that the data bit error rate (BER) is elevated above a specified level.