BlockFLEX: An Adaptive and Survivable Architecture with Hierarchical Routing for LEO Satellite Networks

TL;DR

BlockFLEX introduces a two-tier architecture for LEO satellite networks: a Dynamic Adaptive Block Network (DABNet) underlay that partitions satellites into autonomous blocks to absorb topology volatility, and a Hierarchical Routing (DABR) overlay that couples convergence-free inter-block geographic routing with convergence-isolated intra-block routing. It combines a dual-mode forwarding policy, protection via nBAS, and distributed source-satellite selection (OS3) to achieve high survivability and low overhead under significant ISL failures. The approach is validated on Starlink and OneWeb scale-models, showing up to 2x reachability improvement, near-100% routing availability under moderate failures, and substantial reductions in control overhead and latency jitter. These results indicate BlockFLEX can provide robust, scalable, and efficient routing for future mass-user LEO networks while maintaining terrestrial interoperability through a hierarchical addressing framework.

Abstract

This paper presents \textbf{BlockFLEX}, an adaptive and survivable architecture with a hierarchical routing scheme for Low Earth Orbit satellite networks, designed to address dynamic topology changes and severe link failures. By organizing satellites into autonomous blocks, BlockFLEX establishes a survivable underlay network that masks network volatility and offers a stable overlay view. The architecture employs a hierarchical routing scheme integrating both convergence-free geographic routing and convergence-isolated routing. Furthermore, BlockFLEX adaptively switches between stateful and stateless forwarding modes, enabling efficient, resilient, and stable routing via a dedicated protection mechanism and an optimized source satellite selection algorithm. Experimental evaluations on current operational LEO satellite networks (LSNs) demonstrate that under scenarios with up to 30\% random link failures, the proposed method achieves a $2\times$ improvement in reachability compared to current leading schemes, while maintaining near-100\% routing availability. Moreover, the overhead of control messages and forwarding information base (FIB) updates remains below $0.2\%$ of that in OSPF, accompanied by a $\geq 36\%$ reduction in routing computation time and a $\geq 50\%$ decrease in latency jitter.

Figures (16)

• Figure 1: Today's LEO satellite network architecture.
• Figure 2: The BlockFLEX workflow.
• Figure 3: The DABNet architecture and view.
• Figure 4: Block state transition diagram.
• Figure 5: The hierarchical routing architecture in BlockFlex.