Flow-aware Segment Routing in SDN-enabled Data Center Networks

Abstract

The underlying objective of segment routing is to avoid maintenance of the per-flow state at forwarding devices. Segment routing (SR) enables the network devices to minimize their forwarding table size by generalizing the forwarding rules and making them applicable to multiple flows. In existing works, optimizing the trade-off between segment length and the number of co-flows sharing the segment is considered the key to determining optimal segment endpoints. However, the flow characteristics like the lifetime of flows, and dynamically altering routing paths are critical and impact the performance of SR. Ideally, network flows considered for SR are expected to persist for a longer duration and adhere to static routing paths. But our analysis of flow characteristics at a typical data center reveals that the majority of flows are short-lived. Also, network flows are subject to alter their routing paths frequently for several reasons. Considering short-lived flows and flows that dynamically alter their routing paths may lead to choosing unstable segment endpoints. Hence, it is necessary to study the flow characteristics for determining more stable segment endpoints. In this paper, the authors implemented the SR technique considering the flow characteristics at an SDN-enabled data center and the results show a significant improvement with respect to the stability of segment endpoints.