# Mitigating DDoS Attacks in LEO Satellite Networks Through Bottleneck Minimize Routing
## 1 Introduction  
### System Context and Challenge  
Satellite communication systems have undergone a fundamental paradigm shift in their operational and governance models. Although the satellite-communications sector was long dominated by government agencies and international consortia (e.g., NASA and ESA), it has recently experienced an unprecedented surge in commercial participation. Private entities such as SpaceX's Starlink, Telesat, and OneWeb are now spearheading the deployment of LSNs through mega-constellations, aiming to deliver global broadband coverage [1]. From a service perspective, satellite Internet bridges critical gaps where terrestrial infrastructure is impractical [2], such as maritime, aviation, and rural regions [3]. According to statistics published by the International Telecommunication Union (ITU) as of 2022, approximately 2.7 billion individuals worldwide remain unconnected to the Internet, highlighting a persistent global digital divide. This disparity is further underscored by the uneven distribution of connectivity: while 82% of urban populations had adopted Internet access, this figure represents approximately 1.8 times the adoption rate observed in rural areas [4]. However, challenges remain in spectrum coordination, orbital debris mitigation, and energy efficiency for satellite power systems. These factors will shape the next evolution of LEO networks. As shown in Figure 1, the LSN consists of an inter-satellite link (ISL) consisting of a large number of satellites, and a ground-satellite link (GSL) for ground coverage. Modern LSNs leverage ISLs to achieve two critical advantages: ultralow latency through optimizedorbital routing, and enhanced throughput via spatial multiplexing. Beyond technical merits, their global footprint addresses critical connectivity gaps in terrestrial infrastructure, enabling emergency response [5], remote scientific expeditions, and disaster recovery operations. The commercial viability of this model is evidenced by SpaceX's milestone of 4 million subscribers as of September 2024 [6], accompanied by rapid constellation expansion. As of 8 April 2025, orbital registries document 11,414 operational satellites in Earth's orbit, with SpaceX's Starlink constellation dominating the landscape. Quantitative analysis from [7] reveals that 7161 Starlink satellites are currently active--constituting 62.7% of all active orbital assets. This unprecedented concentration underscores Starlink's dominance in global satellite infrastructure, far exceeding the cumulative deployments of all other operators combined. In accordance with the FCC report [8], we adopted the Starlink S1 shell topology, which has 72 orbital planes, each with 22 satellites, a height of 550 km, and an orbital inclination of 53\({}^{\circ}\), each with 4 lSLs. Previous research on satellite networks has predominantly focused on performance optimization, including communication capacity enhancement [9; 10], latency reduction through ISL routing [11], and novel constellation designs [12]. However, the rapid commercialization of LSNs has introduced new security challenges that remain insufficiently addressed. In contrast to traditional satellite networks operated by governmental agencies, commercial mega-constellations often prioritize scalability and cost-efficiency, which often results in cybersecurity being treated as a secondary concern. For instance, the dense mesh topology of ISLs, while enabling low-latency routing, creates a larger attack surface for adversaries to exploit [13]. Recent studies highlight risks such as spoofing attacks on GSLs [14], and eavesdropping threats on satellite signals [6]. These systemic vulnerabilities pose critical risks to mission-critical operations, extending beyond launch platform integrity to encompass ground and space-based communications infrastructure, telemetry networks, spacecraft tracking mechanisms, and mission-critical command subsystems [15].