Virtual Network Function Allocation to Maximize Continuous Available Time of Service Function Chains With Availability Schedule
Virtual Network Function Allocation to Maximize Continuous Available Time of Service Function Chains With Availability Schedule
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DOI：
10.1109/tnsm.2020.3007712
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发表时间：
2021-06
影响因子：
5.3
通讯作者：
R. Kang;Fujun He;Takehiro Sato;E. Oki
中科院分区：
文献类型：
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作者：
R. Kang;Fujun He;Takehiro Sato;E. Oki
以网络中业务功能链（sfc）连续可用时间最大化为目标，提出了虚拟网络功能（VNF）时隙序列分配的优化模型。该模型抑制了因虚拟机不可用和VNFs重新分配而导致的业务中断。该模型根据虚拟机可用性计划计算一系列时隙中的VNF分配，该计划提供了每个时隙中每个虚拟机的可用性信息。我们将所提出的模型表述为一个整数线性规划（ILP）问题，其目标是最大化每个SFC中最长连续可用时隙的最小数量，并证明了VNF分配问题（VNFA）的决策版本是np完全的。随着ILP问题规模的增大，该问题难以在实际时间内解决。我们开发了一种启发式算法来解决VNFA问题。数值结果表明，与部分考虑虚拟机不可用或VNF重新分配的现有模型相比，该模型提高了sfc的连续可用时间。我们观察到所提出的模型与路由的考虑一起减少了请求的路径长度。开发的启发式算法比ILP方法更快，并且性能损失有限。
This paper proposes an optimization model to derive the virtual network function (VNF) allocation of time slots in sequence aiming to maximize the continuous available time of service function chains (SFCs) in a network. The proposed model suppresses service interruptions otherwise created by the unavailability of virtual machines (VMs) and the reallocation of VNFs. The proposed model computes VNF allocation in a series of time slots based on a VM availability schedule, which provides information on the availability of each VM in each time slot. We formulate the proposed model as an integer linear programming (ILP) problem with the goal of maximizing the minimum number of longest continuous available time slots in each SFC. We prove that the decision version of the VNF allocation problem (VNFA) is NP-complete. As the size of ILP problem increases, the problem is difficult to solve in a practical time. We develop a heuristic algorithm to solve the VNFA problem. Numerical results show that the proposed model improves the continuous available time of SFCs compared with existing models, which partially consider VM unavailability or VNF reallocation. We observe that the proposed model together with a consideration of routing reduces the path length of requests. The developed heuristic algorithm is faster than the ILP approach with a limited performance penalty.