Reconfiguration of virtual network mapping considering service disruption

Network Virtualization (NV) offers an efficient usage of resource by sharing the infrastructure with different virtual network operators while deploying new services. However, it also raises new challenges for network operators and researchers [1]. One of the main challenges is the efficient resource allocation, known as virtual network (VN) mapping problem. In a dynamic scenario, where VN requests come and leave dynamically, the ability to reallocate the currently-mapped networks allows to enhance the resource utilization. But it also leads to the service disruption of reconfigured virtual networks. In this paper, we study the problem of virtual network reconfiguration taking into account the cost incurred by the disrupted services. Most of the recent research on this topic just focused on the acceptance ratio of the virtual networks but didn't address the possible service disruption during the reconfiguration. This paper proposes a reconfiguration mechanism, which is triggered whenever a new coming virtual network request cannot be mapped on the current network. The mechanism re-allocates the currently-mapped networks to accommodate the new request, provided that the minimized cost of reconfiguration doesn't not exceed the gain from mapping the new request. The approach is mathematically formulated as Integer Linear Programming (ILP) problem that maximizes the net gain of the reconfiguration. Its performance is then evaluated and analysed thoroughly through extensive simulations. Finally, a heuristic is proposed to shorten the solving time of the ILP problem while maintaining its performance.