Demand-wise shared protection network design with dual-failure restorability

The availability requirements placed on core communication networks have been rapidly increasing. As the value of the traffic served by these core networks has increased so has the impact of failure. Demand-wise shared protection (DSP) was developed to provide failure survivability in the network that was more efficient than concurrently routing two paths of traffic (1+1 APS), yet was more straightforward to manage than more complex schemes. The DSP model was adapted to ensure, in addition to 100% single failure survivability, a specified minimum level of dual-failure restorability. The effect of enforcing dual-failure restorability in DSP networks was evaluated in terms of cost and overall increases in availability. Counter-intuitively, it was found that in some cases, requiring some specified dual-failure restorability levels can result in decreased availability. DSP was effectively adapted to ensure dual-failure restorability, however, in order to capitalize on the capacity sharing aspects of the model, networks must be sufficiently well connected.