ATM network resilience

With the prospect of widespread deployment of ATM by public network operators, it is crucial to ensure resilience to network outages caused by cable breaks and node failures. The general aim of resilience is to make network failures transparent to users. If a failure happens to affect a circuit, it would be very desirable to reconfigure that circuit as quickly as possible with no information loss. However, if this functionality incurs a significant cost overhead, it may be necessary to charge customers according to the resilience they receive. Since user requirements vary from service to service, it is highly likely that different customers will demand variable levels of resilience. For example, mission-critical business-oriented data services will rely on virtually fault-transparent service, whereas residential customers may tolerate breaks in service as long as they do not occur frequently or last a long time. Fortunately, different ATM restoration mechanisms are possible which suit varied customer requirements. This article summarizes a range of research papers describing ATM restoration techniques. The viable options to provide ATM network resilience are discussed, along with the customer requirements which they satisfy and aspects of ATM resilience being assessed by standards bodies. Taking all such matters into consideration, conclusions are drawn on the current and future scope for ATM resilience