Algorithms for finding robust and sustainable network flows against multilink-attack

This work improves algorithms for finding network flows both sustainable and robust against multilink-attack (MLA). It brings out the relationship between sustainability (flow solution before attack known as MLA-reliable flow) and robustness (flow value after attack known as MLA-robust flow). Both problems are known to be NP-hard. However, exact polynomial time algorithms exist for certain categories of network. It includes the Extended Multiroute Flow (EMRF) algorithm that exhibits a solution to both MLA-robust and MLA-reliable flows. The class of networks solved by EMRF is extended here by using a capacity differentiation method. Although, the previous best-known approximation algorithm to both problems is the naturally robust and sustainable multiroute flow algorithm. A deeper analysis of EMRF an MLA problems leads to new methods to find tighter upper and lower bounds. The success rate of EMRF and the quality of the approximation is evaluated on practical networks as complex networks or grids.