Shared backup resource assignment for middleboxes considering server protection capabilities

摘要

Middleboxes provide a wide range of functions and realize the network. If network functions fail and cannot be recovered, network services which utilize them cannot continue. In order to improve survival probabilities of functions, this paper presents six strategies which obtain an assignment of backup servers to network functions. Backup servers have capabilities of protecting functions and recovering some of them. In the previous work, the range of server capabilities, where an assignment can be obtained, is limited. By adopting the idea of temporarily dividing each server into a set of small servers, we expand the range of server capabilities in the first two strategies. We also consider the applicability of one of the first two strategies through deriving three theorems. Furthermore, in the last four strategies, we enable to obtain an assignment without any limitation of server capabilities by utilizing the knowledge of the first two strategies. To compare our strategies, we also provide a baseline strategy, which is a greedy algorithm and try to balance burden of each server. The numerical results show that in all the settings, more than one of our strategies provides the higher survival probability than the baseline strategy within an allowable computation time.