**Session Date/Time:** 10 Nov 2022 09:30

# tvr

## Summary
The "Time-Variant Routing" (tvr) BoF session explored the problem statement, use cases, and potential solutions for routing protocols that can proactively adapt to predictable network changes. The session addressed whether there is sufficient interest within the IETF community to pursue this work, including whether people are willing to contribute to the development of relevant drafts and code. The discussion covered a range of potential applications, from resource-constrained nodes to mobile networks and carbon-aware routing, and highlighted the need for a well-defined scope and a focus on achievable goals.

## Key Discussion Points
*   **Problem Statement:** Routing protocols typically react to failures. The focus of the BoF is on networks where link or node changes are predictable or can be scheduled. This information can be leveraged for pre-computation and smoother transitions.
*   **Use Cases:**
    *   Resource Preservation: Nodes adapting their functionality to preserve local resources (battery power, storage).
    *   Adapting to External Conditions: Nodes reacting to changing external conditions (power costs, data costs).
    *   Mobile Networks: Handling link changes due to node movement (LEO satellites).
    *   Carbon-Aware Networking: Steering traffic based on the carbon intensity of electricity sources used by network infrastructure.
*   **Dynamic Topology:** Discussion on whether dynamic topology should be in scope. There was agreement that predictability is key, but there was some concern about the complexity of highly chaotic environments.
*   **Existing Technologies:** How current technologies handle the scenarios laid out.
*   **Scope:** Suggestions to start with simple cases, stay focused and narrow the scope of initial work. Specific suggestions included initially focusing on how information could be represented and shared, and de-prioritizing the creation of schedules.
*   **DTN:** Discussion around DTN as a potential technology. It was clarified that DTN is not a routing protocol and would consume the routing information from a potential TBR solution.
*   **Management:** Consideration of the need for management of multiple time variant scenarios through mechanisms like netconf.
*   **Deployment:** A need to show how the components can be mixed together to build a system that actually delivers value.

## Decisions and Action Items
*   **Update Problem Statement:** Rick Taylor will work with Adrian to update the problem statement, integrating feedback from the session.
*   **Define Scope:** There was a strong consensus to narrow the scope of the problem to manageable components. The key will be defining what is within scope.
*   **Further Discussion:** Continue discussion on the mailing list to define a scope of deliverables for the routing area.

## Next Steps
*   **Mailing List:** Continue discussion on the mailing list to determine interest in working on a charter, determine what potential charter should look like, determine if participants are willing to work on this.
*   **ISG/IAB Review:** Chairs will work with the ISG and IAB to determine next steps based on the meeting outcomes and mailing list discussion.