Continuously Available Networks

When talking about the up time of a network one of the key considerations is whether scheduled service disruptions are considered downtime. Scheduled downtime does not count as down time in a High Availability network. Unfortunately, users/customers may not see it that way. To them whether an outage is scheduled or unscheduled, the network as still down.

This creates the requirement for continuously available networks. In needs to be designed and operated so that all maintenance and changes to the network can be completed without disrupting normal user/customer operations. This means that all systems need to support dual redundancy, in service software upgrades, and avoid single points of failure in the physical topology of the network.