Shared Backup Allocation Model of Middlebox Based on Workload-Dependent Failure Rate

With the network function virtualization technology, a middlebox can be deployed as software on commercial servers rather than on dedicated physical servers. A backup server is necessary to ensure the normal operation of the middlebox. The workload can affect the failure rate of backup server; the impact of workload-dependent failure rate on backup server allocation considering unavailability has not been extensively stud-ied. This paper proposes a shared backup allocation model of middlebox with consideration of the workload-dependent failure rate of backup server. Backup resources on a backup server can be assigned to multiple functions. We observe that a function has four possible states and analyze the state transitions within the system. Through the queuing approach, we compute the probability of each function being available or unavailable for a certain assignment, and obtain the unavailability of each function. The proposed model is designed to find an assignment that minimizes the maximum un-availability among functions. We develop a simulated annealing algorithm to solve this problem. We evaluate and compare the performances of pro-posed and baseline models under different experimental conditions. Based on the results, we observe that, compared to the baseline model, the pro-posed model reduces the maximum unavailability by an average of 29% in our examined cases.

Automated summary

This paper proposes a shared backup allocation model for middleboxes considering the workload-dependent failure rate of backup servers. The simulated annealing algorithm is used to solve this problem. Experimental results show that the proposed model can reduce the maximum unavailability by an average of 29% compared to the baseline model under different conditions.