A semi‐oblivious approach for robust segment routing in software‐defined wide area networks

Abstract

AbstractIn this paper, we have proposed a robust optimization for offline segment routing in software‐defined wide area networks combining traffic‐aware and traffic‐oblivious methods. Most prior works on segment routing assume accurate estimation of the traffic matrix, which is difficult to obtain due to the measurement costs and wide variations in traffic matrix over time. To deal with traffic uncertainties, an oblivious segment routing technique was previously developed. However, since all possible traffic fluctuations are considered, this leads to a considerable loss of routing performance in normal conditions. Since the traffic usually fluctuates around a normal pattern within a certain lower/upper bound, in this paper, we propose a semi‐oblivious segment routing method that optimizes routing for a predicted probable traffic matrix, while ensuring its robustness by guarantying the worst‐case performance under the fluctuations. Prior works also considered 2‐segment routing that is demonstrated to lead to routing deficiencies in some cases. We have extended the formulation to include 3‐Segment Routing (3‐SR) and using the strong duality theorem, the proposed semi‐oblivious 3‐SR method is formulated as a linear programming problem with an objective to maximize network throughput. We envision to apply this scheme in software‐defined networks where the controller is responsible to compute robust segment routing paths and to configure the edge routers accordingly. Simulation results show that the proposed method, while being robust to traffic fluctuations, significantly outperforms the traffic oblivious methods in normal network conditions and also achieves comparable performance to the models with known traffic matrix.