Business people often believe that in order to have a reliable system, you need reliable components. Using reliable components to build your network certainly helps, but it’s not essential. The task of an engineer is building a reliable whole out of less reliable parts; a well-engineered network built out of somewhat less reliable parts wins from a somewhat less well-engineered network built out of more reliable parts. Which is a good thing, because super-reliable devices and services are much, much more expensive than regular devices and services.
Read the list of the top 4 causes of network downtime here.