Factors affecting the efficiency of Demand-wise Shared Protection

Demand-wise shared protection (DSP) can be thought of as a form of network-level 1:N APS protection scheme. The concept is to split total demand over multiple disjoint routes between each node pair and use one of the routes for protection. Recently referred to as demand-wise shared protection (DSP), this architecture is receiving renewed interest. Especially in high connectivity networks it would seem to offer the prospect of very low redundancy. In our results and others it is surprising, however, that the savings over 1+1 APS are small even when optimally designed. We have therefore tried to understand and explore the factors that affect the efficiency of DSP in terms of features of network topologies and demand patterns. Through this examination, factors affecting the efficiency of DSP are better understood, providing insights into the applicability of DSP as a protection architecture. One of the main insights is that while a k-way split over disjoint routes seems logically to promise ~1/(k-1) redundancy, this is largely overcome by the statistics of increased route length as k becomes greater than two.