Internet exchanges in space#

Iljitsch van Beijnum

• Why: Genuinely novel — an ESA-commissioned study (STARS, prime SINTEF) on whether Internet exchanges can be built on LEO satellites using optical inter-satellite links, with real BGP simulation results. It stress-tests basic protocol assumptions (BGP convergence, layer-2 vs. layer-3 IX models) in an environment where topology changes at 7 km/s.
• What: A feasibility analysis of IX-in-space: motivations (removing the ground bottleneck, cheaper/faster interconnection between LEO constellations like Starlink/OneWeb/Leo/IRIS², new use cases such as alliance-flexible diplomatic peering), hardware reality-check (a Tbps-class 32-port switch at ~€6,000/11 kg/1500 W plus an ARM route server, radiation-hardened), and the finding that satellites move slowly relative to each other, so handovers can be hours apart. SINTEF's BGP simulation showed ~180-second link-down detection; the speaker's FreeRangeRouting-in-Docker setup with tweaked timers plus BFD was "immediately much better." Follow-up proposals include embeddable "PIGS" (Programmable Internet Gateway Subsystems) modules for other satellites, paralleling NASA's Space BACN.
• How: Optical ISLs (~100 Gbps laser links between satellites) replace fiber; BGP sessions are taken down proactively just before leaving communication range; and — the notable architectural conclusion — a mature space IX would almost certainly be layer-3, because a dozen-plus IX satellites each peered with many "peering satellites" would exhaust any sane layer-2 addressing plan. A live interactive demo was made available.
• Where applicable: Currently a study/simulation, not a deployed system — early-stage and ESA/European-program specific. The BGP-over-dynamic-topology lessons (BFD, proactive session teardown, L3 vs. L2 peering economics) generalize to any highly-dynamic interconnect problem.