Session Date/Time: 10 Nov 2022 17:00

cbor

Summary

This meeting covered updates on the Time Tag and CDDL 2.0 specifications, as well as a presentation on DNS message representation in CBOR. Key discussion points included addressing issues with RFC 3339 usage in Time Tag, refining the features and syntax of CDDL 2.0 (including non-literal tag numbers, processing models, annotations, and module structure), and exploring compression techniques for DNS messages in CBOR using packed CBOR.

Key Discussion Points

Time Tag:
- Addressing inconsistencies in RFC 3339 timestamp usage, specifically regarding local time offsets.
- Decision to align Time Tag submission with Sedate's work on extended timestamps.
- Postponing the addition of a third timescale (UT1) to a later version.
CDDL 2.0:
- Emphasis on backward compatibility with CDDL 1.0.
- Discussion of non-literal tag numbers and associated syntax using generic arguments.
- Exploration of extending the CDDL processing model to include validation, features, and annotations.
- Brendan's work on generating a CBOR parser definition from CDDL and related requirements (entry points, annotations for parser guidance, ordered multi-maps, and Imports).
- Module structure and the need for explicit references between modules (rfcs, internet drafts and 3GPP documents)
- Discussion of using annotations in combination with feature mechanisms (with focus on mandatory or optional items).
DNS Message Representation in CBOR:
- Motivation for compressing DNS messages due to fragmentation issues, especially in constrained environments.
- Discussion of the concise format possibly hampering future DNS extensions.
- Considerations for supporting edns0 and DNS stateful operations within the CBOR representation.
- Proposal to include the resource record as a byte string containing the wire format
- Exploration of address and name compression using packed CBOR and implied DNS specific table entries (TLDs).
- Martin received feedback that they should be careful not to over-optimize for compression and introduce unnecessary complexity.

Decisions and Action Items

Time Tag: Submit a pull request for inconsistency identified early next week. Perform the working group last call soon, coordinating submission with the Sedate working group.
CDDL 2.0:
- Consider a separate, small RFC for non-literal tag numbers.
- Further explore annotations and entry points for CDDL through interims and mailing list discussion.
- Explore marrying the "mandatory to understand" concept with dot features.
- Investigate combining shared value and argument table into one list
DNS Message Representation in CBOR:
- Continue working on the backseat board
- Further investigate impact of edns0 and DSOs with the concise format.

Next Steps

Determine the schedule for the next CBOR interim meeting, coordinating with the core group. Decision will be made via the mailing list whether to have one in December or wait until January.
Continue discussion on CDDL 2.0 features and syntax in upcoming interim meetings.
Continue work on refining the DNS Message Representation in CBOR document.