The Truth About 99.999% Telephone Uptime

Most major telecom providers strive for high availability on their lines. They know that businesses require open communications lines to succeed. Any downtime at all could result in dissatisfied consumers or loss of revenue. So, they offer 99.999% uptime.

Especially now, with COVID-19 spreading across the country, people need reliable phone service. Conference calls on Zoom and other platforms must go on. Call centers are now a primary service channel. And we all have to keep in touch with our friends and family…

But here’s the thing:

High availability is just an SLA, and not all SLAs are met. Let’s take a quick look at what 99.999% uptime means, why you’re probably not getting it, and what you can do to fix that.

What Does 99.999% Uptime Mean?

99.999% telephone uptime, or “five nines of uptime,” refer to the amount of time that a phone network is working correctly. When it’s not working, calls drop or don’t go through, resulting in downtime.

Each additional “nine” in an SLA significantly improves the amount of uptime one can expect. But perhaps each additional nine is best understood through downtime per year.

  • 90% (one nine) = 36.53 days
  • 99% (two nines) = 3.65 days
  • 9% (three nines) = 8.77 hours
  • 99% (four nines) = 52.6 minutes
  • 999% (five nines) = 5.26 minutes

Missing only five minutes of call time per year is an impressive feat. It indicates high availability and reliability. And it’s wayyyyy better than only four or even three nines, which could render organizations incommunicado for significant periods each month.

On the other hand, 99.999% uptime ensures that any service outages are short, few, and (probably) far between.

That is, if the five nines claim can be believed…

The Truth Behind the Five Nines Claim

Our friends at PhoneSentry discovered that often, the true uptime for carriers is sometimes around 98%… even if they claim 99.999% telephone uptime!

To be clear, per the chart above, that means days of downtime per year. That’s hours of downtime per month, in some cases.

To learn more about the reality behind the five nines of uptime—and how your credit union can minimize interruptions to service—check out PhoneSentry’s discussion of the topic.

Continue reading »

Recent Posts