A Service Function Chain (SFC) is an ordered sequence of network functions (NFs). With the emerging Network Function Virtualization (NFV) paradigm, NFs can be deployed as software instances on commodity servers, leading to a more flexible provision of network service. However, the flexibility of NFV comes with considerable compromises since virtual network functions (VNFs) introduce significant processing latency overheads. In this article, we design a flexible SFC parallel system called FlexChain, enabling the parallelism among VNFs to reduce the processing latency of SFCs. To leverage the benefits of parallelism, we study the problem of joint optimization over SFC parallelism and placement with the objective of accepting as many requests as possible. Since the problem is proved to be NP-hard, we propose a parallelism-aware approximation placement algorithm with performance guarantees, and an efficient heuristic algorithm for large-scale data center networks. Our simulation results show that FlexChain combined with our placement algorithm can substantially improve the number of accepted flows in the latency-sensitive scenario, and significantly reduce the average latency of accepted flows at the same time.

中文翻译：

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FlexChain：桥接并行化和服务功能链的位置

服务功能链（SFC）是网络功能（NF）的有序序列。借助新兴的网络功能虚拟化（NFV）范例，可以将NF作为软件实例部署在商品服务器上，从而可以更灵活地提供网络服务。但是，由于虚拟网络功能（VNF）会带来显着的处理延迟开销，因此NFV的灵活性会带来很多折衷。在本文中，我们设计了一个称为FlexChain的灵活SFC并行系统，它使VNF之间的并行性能够减少SFC的处理延迟。为了利用并行性的好处，我们研究了针对SFC并行性和布局的联合优化问题，目的是尽可能接受更多请求。由于事实证明该问题是NP难题，我们提出了一种具有性能保证的可感知并行度的近似放置算法，以及一种针对大型数据中心网络的高效启发式算法。我们的仿真结果表明，FlexChain与我们的布局算法相结合，可以在对时延敏感的情况下极大地提高接受流的数量，并同时显着降低接受流的平均延迟。