QUICOPTSAT End-to-end congestion control for broadband networks with satellite tailored QUIC protocol

  • Status
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The main objectives of the project are as follows: 

  • Design novel Congestion Control (CC) mechanisms for the QUIC transport protocol, which deliver acceptable performance over both satellite and terrestrial networks.

  • Prove the effectiveness of the new mechanisms in relevant GEO/NGSO scenarios. 

Both verification and validation campaigns are performed to show that the designed solution satisfies the technical requirements and to evaluate the effectiveness compared to existing options. A particular goal is to attain similar, or possibly higher, performance than can be achieved using a PEP with TCP.  A set of demonstration campaigns use commercial satellite links for both GEO (e.g., Eutelsat Konnect, SES ASTRA) and NGSO (e.g., Starlink), as well as consider migration scenarios (satellite to terrestrial network switching).

The key results of the project are contributed to the Internet Engineering Task Force (IETF) to propose a method for standardisation by the Internet community.


The recently defined QUIC protocol (RFC9000) has been widely deployed across the Internet. This uses TLS 1.3 to encrypt the end-to-end communication. When this Internet path includes a satellite network, the satellite equipment is unable to adapt or proxy a connection and would require explicit configuration and access to the end-to-end encryption keys (RFC9605). This prevents using techniques to mitigate the differences introduced in satellite systems (e.g., PEPs) and therefore introduces performance limitations. The project therefore proposes a different approach to optimise transfers over satellite that utilise the QUIC transport protocol.


An update to the QUIC congestion control will be designed to provide effective performance over satellite systems: increasing throughput and reducing data transfer delay. This improvement is delivered across a wide range of applications using satellite systems, and targets performance close to, or better than, that offered by current TCP-PEP solutions.


The solution provides an update to the transport protocol and proposes this for standardisation within the IETF. This update can be implemented in Internet servers providing a demonstrable benefit when used over or migrating to a NGSO and GEO satellite network.

System Architecture

The project develops an implementation in a QUIC stack. This is evaluated using a range of applications operating over commercial satellite links for both GEO (e.g., Eutelsat Konnect, SES ASTRA) and NGSO (e.g., Starlink), as well as considering migration scenarios (satellite to terrestrial network switching). Configuration and KPI recording is implemented through a web-interface (GUI).

QUICOPTSAT system architecture


The project plan has three phases: 

  • Phase 1: Definition of a technical baseline and preliminary validation of the mechanisms using simulation campaigns in ns-3. 

  • Phase 2: Development of a consolidated technical baseline in a real-world QUIC implementation followed by in-depth analysis over emulation testbeds (DVB-testbed and NGSO link emulators).

  • Phase 3: Demonstration over real-satellite services using real applications.

Current status

The project has finalised a technical specification, and has provided preliminary contributions to the IETF, where the topic has been adopted to start development of IETF standards. The project is now consolidating the simulation analysis to support the assessment of the proposed technical baseline. The next stage is to realise an implementation in a QUIC protocol stack.

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