**Session Date/Time:** 23 Mar 2022 12:00 # taps ## Summary The taps working group session provided updates on existing documents, discussed the upcoming Working Group Last Call (WGLC) for the Implementation draft, and presented a new QUIC mapping document. There was strong support for adopting the QUIC mapping, and a proposal to add a new charter milestone for general protocol mapping documents was introduced. Additionally, a presentation on the PanAPI system, a TAPS-like transport system developed for SCION, offered valuable feedback on the TAPS API design, particularly concerning property handling and the visibility of implementation flexibility. ## Key Discussion Points * **Chairs' Update and Document Status:** * Since IETF 111, the working group has held six interim meetings, focusing on resolving review comments. * The Architecture and API documents have concluded WGLC and received ART and internal deep reviews. The API document has only two open issues remaining. * The Implementation draft is nearing WGLC, with a handful of open issues still to be resolved. * An issue with author lists exceeding the recommended five for RFCs was resolved by some contributors electing to remove their names; justification has been prepared for the IESG for documents still above the limit. * **Document Release Strategy:** * A suggestion was made to release the Architecture and Interface documents for IESG/IETF last call sooner, rather than waiting for the Implementation draft, to distribute the review workload and allow earlier feedback. The chairs acknowledged this for consideration. * **Reviewers for Implementation Draft WGLC:** * A call for non-author reviewers for the Implementation draft's WGLC was made, emphasizing the need for fresh eyes to check for readability, consistency, and comprehension, rather than deep expertise. * Ideally, reviews should be completed within four weeks after IETF 113, around the time of the next interim. No volunteers stepped forward during the session. * **Working Group Schedule:** * The working group plans monthly interims. * It was reaffirmed that the group will meet every other IETF, meaning no meeting at IETF 114, with the next IETF session planned for IETF 115. * **Proposal for Protocol Mapping Milestone:** * A new milestone for the charter was proposed: "producing one or more protocol mapping documents." These documents would illustrate how higher-layer protocols or transport protocols would utilize the TAPS API. This would require Area Director approval. * HTTP was suggested as another protocol that could benefit from a mapping document due to its unclear mapping to TAPS. * **QUIC Mapping Document Presentation (Tommy Pauly):** * Tommy Pauly presented a new draft (`draft-pauly-taps-quic-mapping-00`), providing an example of how TAPS can be used with QUIC. * The document defines what happens when TAPS API calls are used with QUIC, focusing on establishment, tear-down, and data transfer. * **Key Mapping:** A TAPS `Connection` maps to a QUIC `Stream`, and a TAPS `Connection Group` maps to a QUIC `Connection`. * It details how TAPS functions like `Initiate`, `Cloning`, `Sending`, `Receiving`, `Closing`, and `Aborting` map to QUIC stream and connection operations, including 0-RTT support for `Initiate`. * **Feedback:** * Suggestions to add a high-level summary of the mapping's use cases ("what is this good for / not good for") and to include QUIC datagram mapping within the document for completeness. * Discussion on how TAPS handles QUIC's `STOP_SENDING` frames; it's not a general TAPS API feature but could be exposed as protocol-specific metadata. * Confirmation that the mapping is sufficient for implementing an HTTP/3 client/server, possibly with protocol-specific metadata for stream IDs. * Clarification that TAPS `Connection Groups` can encompass both reliable (streams) and unreliable (datagrams) flows on the same underlying QUIC connection. * A need for "background information and surveys" within mapping documents, not just direct mappings, to address nuances. * **PanAPI System Presentation (Thorben Krüger):** * Thorben Krüger presented PanAPI, a TAPS-like transport system developed for SCION (a future internet architecture focusing on path awareness). * PanAPI uses the TAPS API as its front-end and is implemented in Go, with a web-based scripting backend. It supports TCP, UDP, QUIC, and UDP/QUIC over SCION. * **Design Choices/Departures from TAPS:** * Explicit SCION support added. * **No Event System:** PanAPI leverages Go's native concurrency model (blocking calls, background dispatching for asynchronicity), finding an event-based system unintuitive for Go developers. * **Strongly Typed Objects for Properties:** A design choice to catch errors at compile time, which proved challenging. * Most TAPS concepts map well to SCION, but "active probing" (pinging alternative paths for latency) is a SCION-specific feature without a direct TAPS equivalent. * **Feedback for TAPS API:** * **Property Stages:** The TAPS drafts do not explicitly distinguish between mutable "preference" properties (settings) and converged "truth value" properties (results of selection). This dynamic behavior is difficult for statically-typed languages and could benefit from clearer conceptual distinction in the specification. * **Event System Visibility:** The current documentation on the flexibility to implement TAPS without an explicit event system (mentioned in an appendix) should be more prominently placed in the main document. ## Decisions and Action Items * **Decision:** The working group expressed strong support for adopting the QUIC Mapping document (`draft-pauly-taps-quic-mapping-00`). * **Action Item:** Aaron Falk (chair) will solicit non-author reviewers for the Implementation draft WGLC via the mailing list. * **Action Item:** The chairs will seek Area Director approval for the proposed new charter milestone for protocol mapping documents. * **Action Item:** Tommy Pauly to consider incorporating QUIC datagram mapping and a high-level summary of the mapping's specific use cases into the QUIC mapping document. * **Action Item:** Brian Trammell to address GitHub issue #1009, clarifying that TAPS implementations are not strictly required to be event-based, aiming for a PR by the end of the IETF break. * **Action Item:** Rhys Engert (chair) to ensure the QUIC mapping document is properly associated as a related document in the DataTracker. ## Next Steps * The Implementation draft WGLC is planned to open after IETF 113, following resolution of current issues and securing reviewers. * Further discussion on potential protocol mapping documents (e.g., HTTP) is encouraged. * The next working group interim meeting is tentatively scheduled for early May.