[Podcast] IP networking in deep space

This episode of PING is a conversation with Marc Blanchet from Viagenie in Quebec, Canada. Marc has been active in Internet protocols and the IETF for decades, most recently focused on Internet Protocol communications in deep space. Marc presented at the recent APRICOT 2026 / APNIC 61 meeting held in Jakarta.

We're now used to the idea of IP working in low Earth orbit. Services like Starlink deliver high-speed connectivity that, in many rural and remote areas, can outperform terrestrial networks. We've also relied on IP delivered via geostationary satellites, such as DirecTV, but these have become far less popular for one simple reason - very long end-to-end delay (latency). The half-second round-trip delay to a Geosynchronous Equatorial Orbit (GEO) satellite is something most users find unacceptable. And once you move beyond the Earth's orbit, the challenges only get worse.

Marc's work looks well beyond the familiar orbital 'shells' around Earth. It explores IP networking over much greater distances, from the Moon and the asteroid belt to other planets. In these environments, delay isn't just an inconvenience. It fundamentally affects how networks behave. Long round-trip times have serious consequences for protocols like TCP, which rely on a steady stream of acknowledgements (ACKs) to manage sending rates, estimate delay, and trigger retransmissions.

Marc has been working on simulating the effects of extremely long delays using Earth-based virtual hosts and software. His approach uses the Linux TUN device, TC-NETEM, and code developed by his team. This setup allows them to programmatically define experiments that introduce delay, loss, and packet reordering, with packet-in-flight times that can span hours. It also makes it possible to study how switches, routers, and other intermediate elements behave in an end-to-end IP exchange.

Recent code changes that represent delay as a 64-bit value mean it is now theoretically possible to test IP networking out to the edge of the galaxy - assuming you could keep the machines running for that long.

If we look at what we actually need from IP networks in deep space, TCP is not a good fit for running applications. A better option is QUIC, a more modern, session-layer-style protocol that can run over unreliable transports like UDP, and that combines transport-layer security and IP address agility within a single design.

As Marc discusses in this episode, IP in space is already a reality. Mobile 4G base stations have been deployed on the Moon, and Chinese researchers are experimenting with QUIC. At the same time, the IETF is actively exploring protocol options for space environments through the TIPTOP Working Group.

Read more about IP in space on the APNIC, Viagenie, and IETF websites:

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