Redundancy: what happens when one connection fails?

As long as everything works, redundancy is invisible. On the day a digger cuts through a cable, it's the only thing that counts.

What redundancy is

Redundancy means there is a second route if the first one fails. Not as a spare part in a cabinet, but as a connection that takes over: ideally without anyone noticing.

The core of it lies in the word independent. Two connections that run down the same street, through the same cable duct or end up with the same provider fail at the same time. Then you have two subscriptions and one risk.

Redundant, or just doubled?

Truly redundant

Two connections via physically separate routes
From different providers, or via different technologies
Equipment that switches over automatically
Demonstrably tested, not just intended

False redundancy

Two lines through the same cable duct
Two subscriptions on the same underlying network
A backup connection that has to be switched manually
A second line that has never been tested

Why this matters more than it used to

When files still sat on a server in the building, an organisation could ride out an outage. Now email, telephony, documents and often the core applications run in the cloud. If the connection drops, work stops, not part of it, all of it.

In commercial premises and shopping centres the effect is even more direct: the process stops, or payments can't be processed. For data centres, redundancy isn't a quality feature but a condition for existing at all.

How the IT-Label looks at it

Redundancy is one of the points where the higher levels distinguish themselves. At IT1+ PREMIUM, redundant fibre optic connections are part of the starting point. At lower levels there is usually a single connection: which can be perfectly fine, as long as you know it and factor it in.

The question to ask

Don't ask a landlord whether there is redundancy, but what happens when the main connection fails. Does something take over? How fast? Who notices? And has that ever been tested, or is it an assumption?

In a certified building, that question has already been answered: the IT-Label assesses not only whether facilities are present, but also whether they actually function. See what to look out for as a tenant.

How does your building measure up?

A certified partner assesses redundancy as part of the audit.

How the audit works

Related information

Request an IT-Label