Network operators compose Service Function Chains (SFCs) by tying different network functions (e.g., packet inspection, flow shaping, network address translation) together and process traffic flows in the order the network functions are chained. Leveraging the technique of Network Function Virtualization (NFV), each network function can be “virtualized” and decoupled from its dedicated hardware, and therefore can be deployed flexibly for better performance at any appropriate location of the underlying network infrastructure. However, an SFC often incurs high latency as traffic goes through the virtual network functions one after another. In this paper, we first design an algorithm that leverages virtual network function dependency to convert an original SFC into a parallelized SFC (p-SFC). Then, to deploy multiple p-SFCs over the network for serving a large number of users, we model the deployment problem as an Integer Linear Program and propose a heuristic, ParaSFC, based on the Viterbi dynamic programming algorithm to estimate each p-SFC’s occupation of the bottleneck resources and adjust the processing order of the p-SFCs in order to approximate the optimal solution. Finally, we conduct extensive trace-driven evaluations and exhibit that, compared to the Greedy method and the state-of-the-art CoordVNF method, ParaSFC reduces the average service latency of all the deployed p-SFCs by about 15% through parallelization while accommodating more SFC deployment requests over resource-limited networks.

中文翻译：

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关于服务功能链的有效并行化和近最优部署

网络运营商通过将不同的网络功能（例如，数据包检测、流量整形、网络地址转换）捆绑在一起并按照网络功能链接的顺序处理流量流来组成服务功能链 (SFC)。利用网络功能虚拟化 (NFV) 技术，每个网络功能都可以“虚拟化”并与其专用硬件解耦，因此可以灵活部署以在底层网络基础设施的任何适当位置获得更好的性能。然而，当流量一个接一个地通过虚拟网络功能时，SFC 通常会产生高延迟。在本文中，我们首先设计了一种利用虚拟网络函数依赖将原始 SFC 转换为并行化 SFC (p-SFC) 的算法。然后，为了在网络上部署多个 p-SFC 为大量用户提供服务，我们将部署问题建模为整数线性规划，并提出了一种基于维特比动态规划算法的启发式 ParaSFC 来估计每个 p-SFC 对瓶颈资源并调整 p-SFC 的处理顺序以逼近最优解。最后，我们进行了广泛的跟踪驱动评估并表明，与 Greedy 方法和最先进的 CoordVNF 方法相比，ParaSFC 通过并行化将所有部署的 p-SFC 的平均服务延迟降低了约 15%，同时在资源有限的网络上容纳更多 SFC 部署请求。基于Viterbi动态规划算法估计每个p-SFC对瓶颈资源的占用，调整p-SFC的处理顺序以逼近最优解。最后，我们进行了广泛的跟踪驱动评估并表明，与 Greedy 方法和最先进的 CoordVNF 方法相比，ParaSFC 通过并行化将所有部署的 p-SFC 的平均服务延迟降低了约 15%，同时在资源有限的网络上容纳更多 SFC 部署请求。基于Viterbi动态规划算法估计每个p-SFC对瓶颈资源的占用，调整p-SFC的处理顺序以逼近最优解。最后，我们进行了广泛的跟踪驱动评估并表明，与 Greedy 方法和最先进的 CoordVNF 方法相比，ParaSFC 通过并行化将所有部署的 p-SFC 的平均服务延迟降低了约 15%，同时在资源有限的网络上容纳更多 SFC 部署请求。