Many state-of-the-art Segment Routing (SR) Traffic Engineering (TE) algorithms rely on Linear Program (LP)-based optimization. However, the poor scalability of the latter and the resulting high computation times impose severe restrictions on the practical usability of such approaches for many use cases. To tackle this problem, a variety of preprocessing approaches have been proposed that aim to reduce computational complexity by preemtively limiting the number of SR paths to consider during optimization. In this paper, we provide the first extensive literature review of existing preprocessing approaches for SR. Based on this, we conduct a large scale comparative study using various real-world topologies, including recent data from a Tier-1 Internet Service Provider (ISP) backbone. Based on the insights obtained from this evaluation, we finally propose a combination of multiple preprocessing approaches and show that this can reliably reduce computation times by around a factor of 10 or more, without resulting in relevant deterioration of the solution quality. This is a major improvement over the current state-of-the-art and facilitates the reliable usability of LP-based optimization for large segment-routed networks.

翻译：许多最先进的段路由（SR）流量工程（TE）算法依赖于基于线性规划（LP）的优化。然而，后者的可扩展性较差以及由此产生的高计算时间，严重限制了这类方法在许多实际场景中的可用性。为解决这一问题，研究者提出了多种预处理方法，旨在通过提前限制优化过程中需考虑的SR路径数量来降低计算复杂度。本文首次对现有的SR预处理方法进行了全面的文献综述。在此基础上，我们利用多种真实世界拓扑（包括来自一级互联网服务提供商（ISP）骨干网的最新数据）开展了大规模比较研究。基于评估中获得的见解，我们最终提出了一种结合多种预处理方法的方案，并证明该方案能够可靠地将计算时间减少约10倍或更多，而不会显著降低解的质量。这是相对于当前最新技术的重大改进，并促进了基于LP的优化在大型段路由网络中的可靠可用性。