MegaCacheX: Towards Cost-Effective Hierarchical Collaborative Content Caching in Emerging Mega-Constellations

TL;DR

MegaCacheX introduces a hierarchical, cost-effective satellite-based content caching framework that significantly reduces latency in global content delivery by optimizing collaborative caching across space and ground nodes.

Contribution

It presents a novel hierarchical caching framework that integrates content popularity, regional demand, and satellite trajectories for efficient space-based content distribution.

Findings

Reduces global content access latency by ~36%.

Achieves cost efficiency in satellite content caching.

Demonstrates effectiveness on a containerized microservices testbed.

Abstract

Significant latency in global content delivery primarily arises from insufficient terrestrial infrastructure. Deploying space-based content delivery networks within emerging mega-constellations provides an effective means to bridge the digital divide. However, space-based caching faces constraints from physical-layer dynamics, including dynamic topologies, time-varying inter-satellite link conditions, and limited onboard energy. In addition, existing mechanisms often lack fine-grained content categorization and global optimization. This paper proposes MegaCacheX, a cost-effective hierarchical framework for collaborative content distribution that achieves "Earth-independence" by providing cloud services directly from space. Specifically, data centers in Sun-synchronous orbit act as primary content sources, while caching nodes in mega-constellations and ground stations collaboratively form a distributed edge layer. MegaCacheX optimizes caching strategies by integrating content popularity, regional user distribution, and satellite trajectory predictions. Multi-tier caching nodes serve as service anchors, enabling seamless content delivery with low latency. A prototype implemented on a microservices-based, containerized testbed demonstrates that MegaCacheX reduces global content access latency by about 36% compared to baseline approaches, while maintaining cost efficiency.