European Space Agency

On-Board IP Router (OBR) Development of on-board Internet Protocol (IP) Router Protocol Stacks for Future Satellite Systems


The objective of this activity is to achieve a critical assessment of the state-of-the-art on-board IP routing capabilities, to derive potential operational scenarios for other on-board higher-layer capabilities in various market segments, and to develop prototypes for key SW/HW components for higher-layer functionalities on board GEO and non-GEO satellite systems.

OBR Project aims at:

  • Investigating use cases and potential benefits from such a deployment of on-board routers and other network components.
  • Seamless integration of IP terrestrial networks with LEO satellite constellation networks.
  • Seamless integration of on-board IP devices with terrestrial IP networks.  


The key issue in this project is the definition and selection of viable test cases and identification of the most promising on-board networking functions and solutions for the efficient interworking with terrestrial network functions.

Further challenge is the development of an appropriate testbed for validating the selected networking functions in an emulated integrated satellite-terrestrial communication network. The testbed must be flexible enough to emulate – in real-time –various networking functions in a possibly dynamic satellite constellation while remaining interoperable with the terrestrial network.


The utilization of on-board networking functions has a potential for relieving the terrestrial networks via by-passing congested terrestrial sub-network segments. Furthermore, IP capability on-board satellites enables multiple payloads to be separately addressed e.g. as IP hosts, ensuring segregation and improving security.


The new generation of broadband satellite communications networks aims at complementing and extending the existing terrestrial networks to provide global coverage. The satellite communications networks can provide on demand broadband data and voice services anytime and anywhere. The future broadband satellite networks may use LEO satellite constellations, GEO satellites or a combination of both. The satellite constellations and the terrestrial networks merge into an integrated dynamic communications network.

Currently, only isolated solution exists where limited network functionalities have been deployed within the space segment.

Assuming such a deployment, an integrated network would emerge, spanning all segments. The satellites, ground stations, access routers, other routing devices and user terminals could be considered as fixed or mobile nodes belonging to the same dynamic network.

Furthermore, A technique has been developed and demonstrated that provides bidirectional reachability and routing among legacy IPv6 nodes (both on-board and on-ground) over LEO constellation networks. Real-time testbed with both software based virtual machines and Xilinx ZYNQ Ultra scale SoC demonstrating these techniques, among other protocols that could be deployed over LEO constellations.

The demonstration of SDN (Software Defined Networking) employment over LEO constellations has been a further feature of the project.

System Architecture

The following figures show the anticipated system architecture implementing the desired entities as Virtual Machines for LEO and GEO satellite constellation networks and terrestrial networks and the demonstrator


The system architecture of the testbed allows the emulation of use cases for utilization of on-board IP router networking functions in integrated satellite and terrestrial network scenarios for the GEO-GEO, LEO-LEO and GEO-LEO SCNs. Furthermore, the system architecture provides a friendly GUI for the corresponding re-configuration of the testbed for emulation of use



The project comprises 7 tasks to be performed in two phases.

Phase 1

Task 1: Critical review of example use cases, constellation options, and on-board networking functions

Task output:

TN1: “Use cases, on-board networking functions, system definition, and justifications”

Task 2: Integration with terrestrial networks and technologies for on-board reconfigurability

Task output:

TN2.1: “Interworking with terrestrial networking functions”

TN2.2: “Remote reconfigurability of on-board networking functions”

Phase 2

Task 3: Definition of communications payload architectures

Task output:

TN3: “Communications payload architecture”

Task 4: Derivation of demonstration testbed technical requirements

Task output:

TN4: “Demonstration testbed technical requirements”

Task 5: Demonstration testbed detailed HW/SW and functional architecture

Task output:

TN5.1: “Demonstration testbed detailed HW/SW architecture and functional architecture”

TN5.2: “Demonstration testbed verification test plan and demonstration scenarios”

Task 6: Demonstration testbed development and integration

Task output:

TN6.1: “Demonstration testbed verification results”

TN6.2: “Testbed demonstration results”

HW1: Demonstration testbed HW

SW1: Demonstration testbed SW

Task 7: Future recommendations and roadmap

Task output:

TN7.1: “Future recommendations and roadmap ”

TN7.2: “Installation and user manual”

Current status


Status date

Wednesday, September 23, 2020 - 13:53