European Space Agency

esaCross - QoS, cross-layer and routing management for integrated services in hybrid networks


The overall objective of the project is to develop a test-bed to study and validate Quality of Service (QoS) based routing in an integrated satellite-terrestrial (hybrid) network. Such networks provide multiple parallel or serial paths between the communication end points at the IP network layer. 

The proposed routing mechanisms shall provide the optimum utilization of the satellite links while supporting mobility of communication partners. As an example, the solution should support safety-critical communication to a flying aircraft that changes its physical position within the hybrid network over time. 

In the same use case, high availability of the end-to-end communication is important. Those networks are based on multiple, independent network services. The project evaluates and tests network failure detection and failover switching mechanisms as part of an overlay network. 

The project develops a functional architecture, a hardware/software design, demonstration scenarios, the actual testbed and a verification test plan to evaluate future cross-layer routing mechanisms.


An integrated satellite-terrestrial solution might also contain parallel paths where one of the paths is exclusively based on terrestrial technologies, while the other is based on the already studied serial hybrid satellite-terrestrial solution.

Depending on the satellite link this might be challenging, since latencies, availabilities, transmission errors might be quite different on the parallel paths. Generic IP routing cannot satisfy these requirements so new methods shall be established for such QoS based routing implementation.

Furthermore, transporting real-time VHF radio services in ATM adds challenges to the design for a compliant integrated satellite network


The testbed supports the evaluation of different routing algorithms that consider performance measurements of the available backbone networks, including satellite and terrestrial links.

Furthermore, the algorithm not only uses a single KPI but collects and aggregates KPIs from different network layers, network protocols and where possible even applications.

It allows the development of an application controlling routing algorithm that supports parallel paths, mobility and provides high end-to-end service availability.


The delivered solution is a testbed to support the testing of future product development.

It enables the evaluation of cross-layer QoS routing functionalities based on standardized real-world use cases.

System Architecture

The basic functionality of the testbed is the simulation of hybrid networks in any combination (serial or parallel) to verify the optimization of cross layer QoS and routing management for the tested user terminals or applications. 

The testbed offers a combination of event-based and steady-state emulation and is composed of the following main building blocks: 

  • Test automation framework
  • Network Simulator
  • User Terminal Emulation 

The test automation framework acts as the controller for setting up the test scenarios/environment and executes the test cases in an automated manner. 

The network simulator is used for emulating the characteristics of the different network types on the IP Layer. 

The user terminal emulation simulates the data connectivity behaviour of a user terminal. 

The testbed is based on COTS hardware being able to simulate three networks with different characteristics.


The project plan comprises 5 tasks as described below: 

Task 1: Theoretical technology research (Identification of user scenarios and Critical review of QoS provision mechanisms and cross-layer link status update mechanisms)

Task 2: Derivation of demonstration testbed technical requirements

Task 3: Design of demonstration testbed HW/SW and functional architecture

Task 4: Demonstration testbed development

Task 5: Deployment recommendations and user manual (Final Review)

Current status

The project was finished with the Final Review meeting in February 2018. During this milestone the User Manual of the Testbed and the Deployment recommendations as outcome of the research and test activities were provided. The testbed will be used for further product improvements in the future.

Status date

Tuesday, June 26, 2018 - 07:12