---
# System prepended metadata

title: Back-on-track meeting on CoRAL (2022-10-28)

---

# Back-on-track meeting on CoRAL (2022-10-28)

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https://datatracker.ietf.org/doc/draft-ietf-core-coral/

Issue reference: https://tzi.de/~cabo/corewgcoralnotif.pdf

## Attendees
* Marco Tiloca
* Carsten Bormann
* Christian Amsüss
* Thomas Fossati

## Pinned Info

* Open issues: https://github.com/core-wg/coral/issues
   - PRs for changes, but self-approve
* List of open points from the first meeting
   - https://hackmd.io/Gnd7ZsTBT3-1o5A-6gS-Bg?both
* CoRAL Roadmap
   - https://hackmd.io/b3s4Ve8JRrK0goTIZ6F3yg
* Biweekly meetings at: https://meet.jit.si/TheCoRALNeedsToGrow
   - 15:30 CET every second Friday
* Previous meetings
   - 2021-04-12 : https://hackmd.io/Gnd7ZsTBT3-1o5A-6gS-Bg
   - 2021-04-23 : https://hackmd.io/rCME8RAySnuuS1PmARzQ7A
   - 2021-05-07 : https://hackmd.io/Sg4duT8gSxa_eRzo0qd_tw
   - 2021-05-21 : https://hackmd.io/c747nqnPRtmE5VVbnN3pqA
   - 2021-05-28 : https://hackmd.io/vrfj-jquRuKhuypg8yiO2g
   - 2021-06-11 : https://hackmd.io/T-xV5sTtSIOooy7yAy3nfA
   - 2021-06-18 : https://hackmd.io/nhQwV-loTpudN1ZNHzxeFQ
   - 2021-06-25 : https://hackmd.io/AMezYzy-SKKTGi9O52GWiA
   - 2021-07-02 : https://hackmd.io/wNqS_lNlRByqVsib10t2bg
   - 2021-07-23 : https://hackmd.io/W2CiW8NtS9Sa2L-49eB07w
   - 2021-09-03 : https://hackmd.io/vIQGHrQpRE-d35Ace2DJsw
   - 2021-09-17 : https://hackmd.io/mnQuussISuSO2Agx4SRsKw
   - 2021-10-01 : https://hackmd.io/sUAHjJUmQrSvMNOGPT3iKA
   - 2021-10-08 : https://hackmd.io/5zUiZsWvSfCuqNQc-OAY3g
   - 2021-10-15 : https://hackmd.io/upCF-PFEQ-ubQLfy0MYz4Q
   - 2021-10-21 : https://hackmd.io/P8AvNxdCRG6RY1C4eyYvUQ
   - 2021-11-05 : https://hackmd.io/qEww5zxRS_21PBWypuboFA
   - 2021-11-19 : https://hackmd.io/hL31EUHRQsWQ-lF8osHRPQ
   - 2021-12-03 : https://hackmd.io/CeoMtQZrSy28ZQxurn964g
   - 2022-01-14 : https://hackmd.io/2MGs5msIQVOd0uz80SyFVA
   - 2022-02-11 : https://hackmd.io/6NPjVADRSFGiIfZu1sdzTg
   - 2022-02-25 : https://hackmd.io/J55j_cyuQByyR33avTmN6Q
   - 2022-03-11 : https://hackmd.io/N7C16wYWR8SnUwIKYjvMLw
   - 2022-04-08 : https://hackmd.io/Rs7w0n_ISd-WojtCqW8GQg
   - 2022-04-22 : No minutes taken
   - 2022-05-06 : https://hackmd.io/UPtbaaz0QfyLBC4aQbnlzQ
   - 2022-05-20 : https://hackmd.io/FXDhWuixRh6ybd8NBKP4Zw
   - 2022-06-24 : https://hackmd.io/Sp7SQjC-RPKsx6KM3gOq3w
   - 2022-07-15 : https://hackmd.io/YvFt5E4ZT8WYO8w6MdFTcw
   - 2022-09-16 : https://hackmd.io/JUtbE466TGaR1BO4Eaqf_A
   - 2022-09-30 : https://hackmd.io/uuwpZ6UmTHyC0m9jIYUC4g

## Users for CoRAL
* https://datatracker.ietf.org/doc/draft-hartke-t2trg-coral-reef/
* https://datatracker.ietf.org/doc/draft-tiloca-core-oscore-discovery/
* https://datatracker.ietf.org/doc/draft-ietf-core-coap-pubsub/ (to be included)
* https://datatracker.ietf.org/doc/draft-ietf-core-dynlink/ (not yet)
* https://datatracker.ietf.org/doc/draft-ietf-ace-oscore-gm-admin/
* https://datatracker.ietf.org/doc/draft-ietf-core-observe-multicast-notifications/

https://datatracker.ietf.org/doc/draft-ietf-core-href/referencedby/
https://datatracker.ietf.org/doc/draft-ietf-core-coral/referencedby/

## HREF

https://datatracker.ietf.org/doc/draft-ietf-core-href/

### Implementation status

Christian's implementation (Python, Rust) as per href-10 (both ongoing)
* https://gitlab.com/chrysn/micrurus
    * With the exception of the authority=true fix
* https://gitlab.com/chrysn/cri-ref
    * For constrained implementations (currently with caveats); can do everything except URI(ref)->CRI(ref).

Thomas' implementation (Go) as per href-10:
* https://github.com/thomas-fossati/href

Carsten's implementation (Ruby) as per href-07:
* Finishing corrections for last test vectors
    * Fundamental problem with Ruby URI module needs to be worked around
* Not yet implemented: PET

#### Test vectors

Official test vectors
* https://github.com/core-wg/href/tree/main/tests

More material for test vectors from Carsten
* https://codimd.ietf.org/2Y2YyFstQ5uenofIGBa4IQ?both
* Plan to make the generator compatible with Thomas' Test Vector format
* Revised based on TF and CA feedback.

More material for test vectors from Thomas (JSON)
* https://notes.ietf.org/z5JRYLyGTLO94zMGoqqfmQ?both
* To be revised following the revision to the test vectors above.

**TO DO**: check PR 47 test vectors against implementations, merge (supports 43/44 and possibly 46)

### Open issues

* Appendix A (and outside): Add selected test vectors
    * https://github.com/core-wg/href/issues/53

* vectors: Annotate with required features
    * https://github.com/core-wg/href/issues/52

* Questions and oddities found updated micrurus implementation
    * https://github.com/core-wg/href/issues/50

* Empty paths with the two no-authority versions
    * https://github.com/core-wg/href/issues/46

* Allowed over-PETting
    * https://github.com/core-wg/href/issues/44

* Can't have overscaped dots
    * https://github.com/core-wg/href/issues/43

### PRs

* Draft text for URI-Scheme-ID registry
    * https://github.com/core-wg/href/pull/57
    * https://github.com/core-wg/href/wiki/uri-schemes-that-we-want-numbers-for
    * https://datatracker.ietf.org/doc/minutes-interim-2022-core-14-202210121600/
    * https://datatracker.ietf.org/meeting/interim-2022-core-14/materials/slides-interim-2022-core-14-sessa-20221012-core-href-00.pdf

* Extra test vectors
    * https://github.com/core-wg/href/pull/47

### Next steps

From IETF 114:

> * Implementation work should take around 6 more weeks after IETF 113. We probably need 1 more interim before a Working Group Last Call.
> 
> * One or two revisions until we are done with the implementation testing, then discuss at an interim, then another revision.

## CoRAL

https://datatracker.ietf.org/doc/draft-ietf-core-coral/

Would be good to have documented a list of application-independent minimal components that have to be implemented to be ready for running/using a CoRAL-based application. Examples:
- "HREF engine"
- "CoRAL document navigator"
- Minimal CoRAL vocabulary

### Open issues

* Linking to local resources
    * https://github.com/core-wg/coral/issues/29

* Embedded representations and their context
    * https://github.com/core-wg/coral/issues/27

* Security model
    * https://github.com/core-wg/coral/issues/21

* Language and direction tags in CBOR literals
    * https://github.com/core-wg/coral/issues/19

* How using forms maps to following links
    * https://github.com/core-wg/coral/issues/17

* CRI vs array literal serialization
    * https://github.com/core-wg/coral/issues/16

* Revisiting the tree serialization
    * https://github.com/core-wg/coral/issues/9

* Default dictionary and dictionary parameter
    * https://github.com/core-wg/coral/issues/6

* Eliding data and must-understand
    * https://github.com/core-wg/coral/issues/3

### Open PRs

* Add tag for packed CBOR by reference
    * https://github.com/core-wg/coral/pull/28

* Add some examples based on STP
    * https://github.com/core-wg/coral/pull/20

### Dependencies (CoRAL use cases)

The following documents depend on CoRAL:

* https://datatracker.ietf.org/doc/html/draft-ietf-ace-oscore-gm-admin: probably take out CoRAL "how to use with CoRAL" and examples into a separate draft (translate from old text form to CBOR EDN; park while CoRAL is completed); close to WGLC otherwise.

* https://datatracker.ietf.org/doc/draft-tiloca-core-oscore-discovery/
translate CoRAL examples (which will be the format to use), add security considerations, then maybe WGA; implemented: mostly a set of RD queries; (discuss registry for target attributes -> Simple separate document; retroactively populate registry with well-known target attributes)

### Next steps

* Expected revision before IETF 115?

### Sync with SDF

AP: generate slideware that extracts the most salient points
- structure of CoRAL
- relationship to RDF (including RDF examples \[PR])
- use of links
- instance vs. class
- potential use in SDF (data, forms, ...)

How far are we from a discussion with Michael Koster & co. ?

## AOB and next meeting

* Next design team meeting on ...
   - 2022-10-25, 14:30 UTC / 15:30 CEST
   - https://meet.jit.si/TheCoRALNeedsToGrow
