Introduction and welcome - Rob Evans (Jisc)

Low Orbit Satellites

Host: Lars Fischer (NORDUnet)

• HydRON project - Josep Maria Perdigues Armengol (ESA)

The ambition of the High thRoughput Optical Network (HydRON) project of European Space Agency (ESA) is to seamlessly extend terrestrial high-capacity networks into space. The concept aims to empower satellite networks by developing terrestrial networking capabilities and features, in order to interconnect all types of space assets by an “Internet backbone beyond the cloud(s)”. Concretely, HydRON will take advantage of space assets to complement terrestrial high-capacity networks, ultimately enabling the configuration of a worldwide and world-first 3-dimensional optical network interconnecting terrestrial networks with different (orbital) layers in GEO, MEO, LEO, and HAPS. The 3-dimensional optical network capabilities will revolutionize the SatCom sector and its related commercial business. This presentation will provide the current status of the planned HydRON Demonstration System (HydRON-DS) to be developed and launched by 2026. The HydRON-DS represents the initial stage serving the purpose to gradually demonstrate key technologies required to deploy a first (all) optical transport network at terabit-per-second capacity in space and the seamless extension of terrestrial fibre-based networks into space.

• Developing a simulation framework and efficient data transport for low-earth orbit (LEO) satellite constellations - George Parisis (University of Sussex)

In this work, we present our simulation framework for experimenting with LEO satellite networks that we built on top of the OMNeT++/INET framework, with support from the GÉANT innovation programme. We discuss the various components of the framework along with challenges we faced in simulating network traffic and protocols with realistically sized constellations, and focus on related optimisations we introduced to eliminate substantial overheads associated with the constantly changing network topology. We present and discuss experimentation on network latency in different constellations and across different locations on Earth and describe significant challenges in designing efficient data transport protocols. Through experimentation we show potential limitations of existing data transport protocols when operating in LEO satellite networks. We propose a receiver-driven data transport protocol that combines in-network packet trimming with edge-disjoint-path routing to provide efficient data transport and improve network utilisation. Finally, we discuss current and future work on delay-based congestion control and RaptorQ codes to efficiently support different types of communication.

• Q&A discussion (15')

Wrap up, Feedback, Summary and Next Steps - Rudolf Vohnout (CESNET)