Design and implementation of a cross-domain content caching and distribution architecture for mega-constellation satellite internet

Content Delivery Networks (CDNs) have played a pivotal role in supporting the rapid evolution of the Internet, managing most of the global data traffic for billions of users. The advent of satellite mega-constellations has significantly enhanced global connectivity, giving rise to multidomain satellite systems composed of specialized functional domains. Integrating caching technologies into these satellite communication systems improves collaborative efficiency among heterogeneous satellites, enhances network scalability, and creates new opportunities to bridge the digital divide. In response to these developments, this paper proposes the Cross-Domain Content Caching and Distribution Architecture for Mega-constellation Satellite Internet (C3DA-MSI), a cross-domain caching and distribution framework tailored for Earth observation scenarios within mega-constellation systems. In this architecture, the control plane of the caching network is deployed on medium-earth orbit (MEO) satellites, which are responsible for disseminating control signals across the network. Popular content is cached and delivered on demand through space-based data centers and service anchors within each functional domain, forming the data plane. Basic inter-domain connectivity is facilitated by cross-domain gateway satellites, resulting in an architecture characterized by "weak inter-domain connectivity and strong intra-domain connectivity." To evaluate the proposed approach, we developed and implemented the cross-domain caching network on a container-based mega-constellation Internet testbed. Experimental results show that, compared to traditional non-cross-domain schemes, the proposed method reduces the content response time by 40% and increases the content service area coverage by 16%.