Dual access rings for communications networks

Abstract

A switching architecture is disclosed which includes a dual access ring structure interconnecting the location of a customer, a primary central office, a backup central office and a remote central office (hub office) which does not directly serve the customer location. The architecture enables transport of a customer's communications traffic to be automatically restored in the event a failure occurs in the primary transport route of the traffic from the customer location to the hub office via the primary central office by automatically selecting a transport route free of a failure. Such a failure is detected whether caused by a so-called 'hard' failure or a so-called 'soft' failure. Optionally, each type of automatic network reconfiguration is executed in a manner such that as soon as it is possible to employ the original configuration, the network automatically reverts to the original configuration, thereby easing network maintenance activity. Corresponding reconfigurations are performed to insure recovery of traffic originating from the hub office and destined for the customer's location. Recovery of communications can typically be provided in a time period on the order of milliseconds, as opposed to days.