**Session Date/Time:** 17 Mar 2026 08:00

# [SPACE](../wg/space.html)

**IETF 125 Session: Systems and Protocol Aspects for Circumstellar Environments (Proposed Research Group)**

## Summary
The SPACE proposed Research Group (RG) met to discuss long-term research regarding space-based networking, orbital computing, and interstellar protocol architectures. The session covered the integration of terrestrial cloud infrastructures with space segments, standardized protocol stacks for Earth-Moon communication, and tools for LEO measurement. Technical presentations also introduced a standardized code for describing satellite constellations and novel approaches for sparse LEO networking and space-based AI infrastructure.

## Key Discussion Points

### Space Cloud Network Infrastructure
**Kanglian Zhao** presented [Bridging the Future Digital Divide with Space Cloud Network Infrastructure](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-bridging-the-future-digital-divide-with-space-cloud-network-infrastructure-00).
*   **Infrastructure Evolution:** Modern space initiatives (Starlink, Amazon Kuiper, Blue Origin's TerraWave) are shifting from "bent-pipe" architectures to integrated space-terrestrial clouds with orbital data centers.
*   **Use Cases:** Identified needs for distributed AI model training in orbit (e.g., EU ASCEND project) and space-based Point of Presence (POP) to reduce latency and ensure data sovereignty.
*   **Architecture:** Proposed a two-layer model consisting of a Cloud Layer (for computation/storage) and an Access Layer (for connectivity). Discussion focused on orbit selection, specifically the benefits of Dawn-Dusk orbits for consistent solar power.

### Earth-Moon Integrated Network Protocols
**He Xiongwen** presented [Protocol Architecture of Earth-Moon Integrated Network](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-he-xiongwen-protocol-architecture-of-earth-moon-integrated-network-00).
*   **Heterogeneous Networking:** Deep space missions (Chang'e, Tianwen) require bridging CCSDS, ECSS, and IETF protocol suites.
*   **Proposed 4-Layer Architecture:**
    *   **Application Layer:** Support for CFDP and ECSS-PUS.
    *   **Transport Layer:** Support for TCP, UDP, and LTP.
    *   **Network Layer:** Integration of Space Packet Protocol (for low-speed links) and IPv6 (for high-speed optical/TSN links).
    *   **Link/Physical Layer:** Convergence of diverse space-to-ground and inter-satellite links.
*   **Implementation:** Mentioned the "Fuxi" software architecture and the deployment of Intelligent Network Units on the Queqiao-2 relay satellite.

### Tools and Measurement
**Nishanth Sastry** presented [Tools and Infrastructures for LEO Measurement and Evaluation](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-tools-and-infrastructures-for-leo-measurement-and-evaluation-00).
*   **LEOscope:** A testbed using Docker-encapsulated experiments deployed behind satellite user terminals.
*   **Observation:** Measuring mega-constellations requires global vantage points; researchers currently rely on browser plugins, public datasets (M-Lab, RIPE Atlas), and simulators.
*   **Community Call:** Requested contributions to a living tools document. **Jörg Ott** suggested starting with a wiki for rapid population before moving to an Internet-Draft.

### Standardizing Constellation Descriptions
**Juan Fraire** presented [Draft update: A Code to Describe Satellite Constellations](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-juan-fraire-draft-update-a-code-to-describe-satellite-constellations-04).
*   **Draft:** `draft-fraire-space-constellation-code-01`
*   **Grammar:** Uses ABNF to describe Walker Star and Walker Delta topologies (altitude, inclination, planes, phasing).
*   **Connectivity Patterns:** Introduced a YAML-based extension to define link patterns (e.g., checkered grid patterns) using simple predicates.
*   **Future Work:** Considering "Flower" constellations (eccentric orbits) and optical terminal constraints (gimbal/slew limits).

### IP-Based Satellite Routing and Computing
**Jing Wang** presented two topics:
1.  [Consideration for IP-Based Satellite Routing Protocol](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-consideration-for-ip-based-satellite-routing-protocol-00) (`draft-wang-space-satellite-routing-considerations-00`).
    *   Challenges include dynamic topologies and limited spaceborne resources.
    *   References potential integration with TVR (Time-Variant Routing) and LISP (Locator/ID Separation Protocol).
2.  [Consideration for Space-Based Computing Infrastructure Network](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-consideration-for-space-based-computing-infrastructure-network-00) (`draft-wang-space-computing-infrastructure-00`).
    *   Proposed requirements for monitoring onboard resources and computing-aware routing to prevent node overload during high-demand events (e.g., disaster monitoring).

### Small-Scale LEO Scaling
**Yuanjie Li** presented [Small-scale LEO Satellite Networking for Global-scale Demands](https://datatracker.ietf.org/meeting/125/materials/slides-125-space-yuanjie-li-small-scale-leo-satellite-networking-for-global-scale-demands-00).
*   **Problem:** High cost and orbital debris risks associated with mega-constellations.
*   **Tiny LEO:** Proposed using "Compressed Sensing" algorithms to design non-uniform, sparse constellations that match global demand density while using significantly fewer satellites.
*   **Geographic Segment Anycast:** To handle frequent topology changes, a routing abstraction was proposed using SRv6 to decouple high-level geographic intent from low-level satellite mobility.
*   **Safety:** Discussed "cascade collision avoidance" where maneuvers in a dense constellation trigger a domino effect of safety adjustments, potentially exhausting fuel budgets.

## Decisions and Action Items
*   **Tools Collection:** The group agreed to establish a centralized repository/wiki for tools and datasets relevant to space networking research.
*   **Constellation Code:** Contributors are encouraged to review `draft-fraire-space-constellation-code` to ensure the YAML structure is expressive enough for varied link constraints (e.g., space-to-ground).

## Next Steps
*   **Draft Progression:** Authors of the routing and computing drafts (`draft-wang-*`) and the constellation code draft will incorporate feedback from the session and the mailing list.
*   **IETF 126 Preparation:** The chairs (Juan Fraire and colleagues) will look to prioritize topics for the next meeting in Vienna, focusing on converging the various tooling and description format efforts.