**Session Date/Time:** 24 Jul 2025 12:30

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# DTN

## Summary

The DTN working group meeting at IETF 123 covered several topics including updates on CoAP over BP, BPSEC COESA context, EID patterns, UDPCL, DTN management architecture (DTMA), BTPU, bundle-in-bundle encapsulation (Vibe), DTN architecture update, DTN reliability and a strong bundle auditing mechanism for BPSEC. The meeting also included a brief update from the IAB and AD regarding open positions and NOMCOM. A recharter discussion was deferred to the mailing list.

## Key Discussion Points

*   **CoAP over BP:**
    *   The draft has been requested for working group adoption at the core working group, keeping DTN informed.
    *   Discussion regarding the payload length option and its implementation with OSCOR.
    *   Concerns were raised about IPN.ARPA and its potential DNS resolvability.  The AD will scrub the document for potential conflicts.
*   **BPSEC COESA Context:**
    *   Updates included adding security source to AAD.
    *   Ready for working group last call.
    *   Concern was raised about key selection based on timestamp and key rollover during bundle transit.
*   **EID Patterns:**
    *   Focuses on the IPN scheme.
    *   Decision deferred as to whether a pattern syntax for DTN URI should be included.
*   **Updated UDPCL:**
    *   Includes extensibility and segmentation capabilities.
    *   Requires more than one implementation and interoperability testing before standardization.
*   **DTMA Updates:**
    *   Updates to AMM, ARI and AMP documents.
*   **BTPU:**
    *   Segment numbering was inverted for better resource management.
    *   Discussion on potential changes to the header (reducing sequence number length, adding flag field).
    *   Proposal to reserve message types for raw bundle encapsulation.
    *   Plans to define how BTPU can run over Ethernet frames.
*   **Bundle in Bundle Encapsulation (Vibe):**
    *   Proposal to remove the retransmission mechanism from B .IBE
    *   Proposed revision on fragmentation and reassembly strategy within Vibe.
    *   Operational experience from testing Vibe between ISS and ground.
*   **DTN Architecture Update:**
    *   Motivation for updating RFC 4838 to IETF engineering stream
    *   Document structure borrowed from RFC 8655
    *   Discussion on custody transfer.
    *   Discussion on flattening the stack
*   **DTN Reliability:**
    *   Informational RFC proposed to define DTN reliability holistically.
    *   Discussion of fault analysis, user indicators, and reliability mechanisms.
    *   Proposal to define classes of reliability for DTNs.
*   **Strong Bundle Auditing Mechanisms:**
    *   A mechanism to ensure integrity by generating auditing block by the source and receipts generated by intermediate nodes.
    *   Concerns were raised about mixing data conveyed with security and using existing bib rather than using BRB

## Decisions and Action Items

*   **CoAP over BP:** AD (Eric) to review the DNS aspects of the IPN.ARPA usage in the draft.
*   **BPSEC COESA Context:** Request for last call to be made on the mailing list. Review by AD
*   **EID Patterns:** Poll closed. Decision is to continue with the current draft which only includes the IPN scheme.
*   **Updated UDPCL:** To remain as a possibly stable document, awaiting a second implementation and interoperability testing.
*   **BTPU:** Solicit working group for ideas on using flag field.
*   **Secure Advertisement and Neighborhood Discovery (SAND):** Discuss open issues on the mailing list.
*   **New Security Association Draft:** Request for adoption to be made on the mailing list.
*   **Safe Draft:** Request for adoption to be made on the mailing list.
*   **DTN Reliability:** Post the initial personal draft to the mailing list to begin discussion.
*   **Buble and Buble Encapulation:** Slides to be passed to the chairs
*   **Presentations:** Chairs to distribute presentations

## Next Steps

*   Continue discussion on remaining topics via the DTN working group mailing list.
*   Schedule a recharter discussion on the mailing list.
*   Proceed with working group last calls as appropriate.
*   Authors to address feedback and comments from the working group on their respective drafts.
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