A Lightweight and Scalable Design of Segment Routing in Broadband LEO Constellations Using Landmark-Based Skeleton Graphs

TL;DR

This paper tackles scalable routing in highly dynamic, resource-limited LEO constellations by introducing LGSR, a landmark-based skeleton graph framework for segment routing. It combines region-based skeleton-path planning with probabilistic multipath forwarding inside regions and hierarchical partitioning to support QoS, along with local table/source routing to handle failures. Theoretical analyses show LGSR dramatically reduces path-calculation and update costs compared to Dijkstra, while preserving near-optimal path quality; simulations across large networks demonstrate superior load balancing and lower latency, with route planning times around 1.8 seconds in large networks versus 108 seconds for Dijkstra. The approach offers a practical, SDN-friendly TE solution for massive LEO deployments, delivering scalable computation, reduced signaling, and robust performance under high dynamics.

Abstract

Emerging Low Earth Orbit (LEO) broadband constellations hold significant potential to provide advanced Internet services due to inherent geometric features of the grid topology. However, high dynamics, unstable topology changes, and frequent route updates bring significant challenge to fast and adaptive routing policies. In addition, since computing, bandwidth, and storage resources in each LEO satellite is strictly limited, traffic demands are typically unbalanced, further enlarging the challenge to scalable routing policies with load balancing. Nevertheless, most existing research failed to address the above difficulties. Therefore, this paper proposes a lightweight and scalable protocol of segment routing through landmark-based skeleton graphs. To improve the overall performance, we design an efficient multipath segment routing algorithm. First, the algorithm partitions the network into multiple regions to construct skeleton paths, which can effectively guide packet forwarding and reduce the operating costs. In each region, multipath probabilistic routing is used to achieve uniform traffic distribution, avoiding hotspot congestion. Furthermore, the flexible hierarchical partitioning and localized segmented routing is employed for fine-grained traffic control and QoS guarantee combined with adaptive local single-path routing. Finally, experimental results validate our method's superior performance in terms of response time and network utility.

Figures (24)

• Figure 1: Illustration of the Walker Delta Constellation
• Figure 2: Partition Schematic Diagram
• Figure 3: Illustration of a Skeleton Path in the Network
• Figure 4: Probabilistic Forwarding within Skeleton Path
• Figure 5: Flow Distribution Visualization