Carrier guarantees range from 99 percent to 99.999 percent, dependent on the carrier and their specific guarantee language. Guarantees are therefore difficult to compare without significant study and understanding of the carrier's specific terminology. However, the means of verifying this fact is undefined. Strong process language must be in place to ensure proper guarantee execution. Additionally, companies must ensure that the carrier has redundant means of gathering SLA data.
Some carriers exclude lost data from throughput calculations.
The mean time to respond is usually four hours if the site is within a predetermined number of miles from a carrier-maintenance center. Longer timeframes are determined by distance from that center. Note that response and restoral totals result in an aggregated outage time of eight hours. It is clear that when negotiating an SLA with the frame-relay carrier, careful study and understanding of their terminology, exclusions, processes, and calculation methodology is critical.