Internet backbones in space

Several "NewSpace" companies have launched the first of thousands of planned satellites for providing global broadband Internet service. The resulting low-Earth-orbit (LEO) constellations will not only bridge the digital divide by providing service to remote areas, but they also promise much lower latency than terrestrial fiber for long-distance routes. We show that unlocking this potential is non-trivial: such constellations provide inherently variable connectivity, which today's Internet is ill-suited to accommodate. We therefore study cost-performance tradeoffs in the design space for Internet routing that incorporates satellite connectivity examining four solutions ranging from naively using BGP to an ideal, clean-slate design. We find that the optimal solution is provided by a path-aware networking architecture in which end-hosts obtain information and control over network paths. However, a pragmatic and more deployable approach inspired by the design of content distribution networks can also achieve stable and close-to-optimal performance.