Low earth orbit (LEO) satellite networks have the potential to provide low-latency communication with global coverage. To unleash this potential, it is crucial to achieve efficient packet delivery. In this paper, we propose a Link-identified Routing (LiR) architecture for LEO satellite networks. The LiR architecture leverages the deterministic neighbor relation of LEO constellations, and identifies each inter-satellite link (ISL). Moreover, LiR architecture adopts source-route-style forwarding based on in-packet bloom filter (BF). Each satellite could efficiently encode multiple ISL identifiers via an in-packet BF to specify the end-to-end path for the packets. Due to false positives caused by BF, the more ISLs are encoded at a time, the more redundant forwarding cases emerge. Based on the topology characteristics, we derive the expected forwarding overhead in a closed-form and propose the optimal encoding policy. To accommodate link-state changes in LEO satellite networks, we propose the on-demand rerouting scheme and the on-demand detouring scheme to address the intermittent ISLs. We also elaborate how to take advantage of LiR architecture to achieve seamless handover for ground-satellite links (GSLs). Finally, we conduct extensive numerical experiments and packet-level simulations to verify our analytical results and evaluate the performance of the LiR architecture.

翻译：低地球轨道（LEO）卫星网络具备提供全球覆盖低延迟通信的潜力。为充分发挥这一潜力，实现高效的数据包传输至关重要。本文针对LEO卫星网络提出一种链路标识路由（LiR）架构。该架构利用LEO星座的确定性邻接关系，为每条星间链路（ISL）分配唯一标识。此外，LiR架构采用基于数据包内布隆过滤器（BF）的源路由式转发机制。每颗卫星可通过数据包内BF高效编码多个ISL标识符，从而为数据包指定端到端传输路径。由于BF固有的误判特性，单次编码的ISL数量越多，产生的冗余转发情况越显著。基于拓扑结构特征，我们推导出闭合形式的期望转发开销表达式，并提出最优编码策略。为适应LEO卫星网络的链路状态动态变化，我们提出按需重路由方案与按需绕行方案以应对间歇性ISL问题。同时详细阐述了如何利用LiR架构实现星地链路（GSL）的无缝切换。最后，通过大量数值实验与数据包级仿真验证了理论分析结果，并评估了LiR架构的整体性能。