Edge (of the Earth) Replication: Optimizing Content Delivery in Large LEO Satellite Communication Networks

TL;DR

This paper investigates optimizing content delivery in large LEO satellite networks by exploring CDN points-of-presence within satellites, proposing four strategies, and demonstrating significant bandwidth reduction through content replication.

Contribution

It introduces four novel strategies for CDN placement in satellite networks and evaluates their effectiveness through extensive simulations, highlighting potential bandwidth savings.

Findings

Content replication reduces bandwidth by 93%.

Storing 0.01% of content per satellite is effective.

Strategies improve latency and operational costs.

Abstract

Large low earth orbit (LEO) satellite networks such as SpaceX's Starlink constellation promise to deliver low-latency, high-bandwidth Internet access with global coverage. As an alternative to terrestrial fiber as a global Internet backbone, they could potentially serve billions of Internet-connected devices. Currently, operators of CDNs exploit the hierarchical topology of the Internet to place points-of-presence near users, yet this approach is no longer possible when the topology changes to a single, wide-area, converged access and backhaul network. In this paper, we explore the opportunities of points-of-presence for CDNs within the satellite network itself, as it could provide better access latency for users while reducing operational costs for the satellite Internet service providers. We propose four strategies for selecting points-of-presence in satellite constellations that we evaluate through extensive simulation. In one case, we find that replicating web content within satellites can reduce bandwidth use in the constellation by 93% over an approach without replication in the network, while storing just 0.01% of all content in individual satellites.