In network functions virtualization (NFV) environments, network security is provided with the deployment of virtual security functions (VSF) on general-purpose servers to filter and monitor the incoming traffic. However, the traffic handled by VSFs may have different security requirements in a network. On the other hand, there are some operational objectives that differ according to the needs of the network such as minimizing cost, latency, and energy consumption etc. Therefore, the issue of placing VSFs considering both security requirements and operational objectives is an important research challenge. In this paper, we tackle the problem of energy-efficient VSF placement (EE-VSFP) to minimize energy consumption while meeting flow-level security requirements as well as resource constraints. We develop an integer linear programming (ILP) model for this problem to minimize server energy consumption, and also propose a novel heuristic algorithm to solve the problem for larger scale network instances within practical time limits. Evaluation results show that our heuristic reduces energy consumption by up to 48 % compared to baseline placement solutions. In addition, we demonstrate that in most cases our heuristic can provide optimal solutions while running much faster than the ILP, and drastically reduces the average flow path length by up to 53 % compared to the ILP.

在网络功能虚拟化（NFV）环境中，通过在通用服务器上部署虚拟安全功能（VSF）来提供网络安全性，以过滤和监视传入的流量。但是，由VSF处理的流量在网络中可能具有不同的安全要求。另一方面，根据网络的需求，有些运营目标会有所不同，例如将成本，等待时间和能源消耗降至最低等。因此，在考虑安全要求和运营目标的同时放置VSF的问题是一个重要的研究挑战。 。在本文中，我们解决了节能VSF放置（EE-VSFP）问题，以在满足流量级安全要求和资源限制的同时，将能耗降至最低。我们针对此问题开发了整数线性规划（ILP）模型，以最大程度地减少服务器能耗，并提出了一种新颖的启发式算法，以在实际的时限内解决大型网络实例的问题。评估结果表明，与基线放置解决方案相比，我们的启发式方法最多可将能耗降低48％。此外，我们证明，在大多数情况下，我们的启发式方法可以提供最佳解决方案，同时运行速度比ILP快得多，并且与ILP相比，可大大减少平均流路长度多达53％。评估结果表明，与基线放置解决方案相比，我们的启发式方法最多可将能耗降低48％。此外，我们证明，在大多数情况下，我们的启发式方法可以提供最佳解决方案，同时运行速度比ILP快得多，并且与ILP相比，可大大减少平均流路长度多达53％。评估结果表明，与基线放置解决方案相比，我们的启发式方法最多可将能耗降低48％。此外，我们证明，在大多数情况下，我们的启发式方法可以提供最佳解决方案，同时运行速度比ILP快得多，并且与ILP相比，可大大减少平均流路长度多达53％。