Shepherd writeup

## Shepherd Writeup

Full HTML version can be found at:


Document Shepherd: [Jaime Jiménez](
Area Director: [Alexey Melnikov](

The existing Constrained Application Protocol (CoAP) methods only allow access to a complete resource.  This does not permit applications to access parts of a resource.  In case of resources with larger or complex data, or in situations where a resource continuity is required, replacing or requesting the whole resource is undesirable.  Several applications using CoAP will need to perform partial resource accesses.

Similar to HTTP, the existing Constrained Application Protocol (CoAP) GET method only allows the specification of a URI and request parameters in CoAP options, not the transfer of a request payload detailing the request.  This leads to some applications to using POST where actually a cacheable, idempotent, safe request is desired.

Again similar to HTTP, the existing Constrained Application Protocol (CoAP) PUT method only allows to replace a complete resource.  This also leads applications to use POST where actually a cacheable, possibly idempotent request is desired.

This specification adds new CoAP methods, FETCH, to perform the equivalent of a GET with a request body; and the twin methods PATCH and iPATCH, to modify parts of an existing CoAP resource.

The document is intended as an Standards Track RFC.

###Review and Consensus

The document has gone through multiple expert reviews and has been discussed on multiple IETF meetings. Before the last IETF the WGLC was completed.

There are no known implementations available.

###Intellectual Property

Each author has stated that they do not have direct, personal knowledge of any IPR related to this document. I am not aware of any IPR discussion about this document on the CoRE WG.

###Other Points
There is a downref to RFC 2616: This is in there because the security considerations of RFC 7252 reference (the now obsoleted) RFC 2616. The authors are not aware of someone having done the work to collect the relevant security considerations from the splinters of RFC 2616 (RFC 7230 and following).


* [x] Does the shepherd stand behind the document and think the document is ready for publication?
* [x] Is the correct RFC type indicated in the title page header?
* [x] Is the abstract both brief and sufficient, and does it stand alone as a brief summary?
* [x] Is the intent of the document accurately and adequately explained in the introduction?
* [x] Have all required formal reviews (MIB Doctor, Media Type, URI, etc.) been requested and/or completed?
* [x] Has the shepherd performed automated checks -- idnits (see and the Internet-Drafts Checklist), checks of BNF rules, XML code and schemas, MIB definitions, and so on -- and determined that the document passes the tests?
` There is no ABNF in this draft`
* [x] Has each author stated that their direct, personal knowledge of any IPR related to this document has already been disclosed, in conformance with BCPs 78 and 79?
* [x] Have all references within this document been identified as either normative or informative, and does the shepherd agree with how they have been classified?
`There is a normative reference to [I-D.ietf-core-block] but that shouldn't be a problem as it is in late stages`
* [x] Are all normative references made to documents that are ready for advancement and are otherwise in a clear state?
* [x] If publication of this document changes the status of any existing RFCs, are those RFCs listed on the title page header, and are the changes listed in the abstract and discussed (explained, not just mentioned) in the introduction? `Does not apply`
* [x] If this is a "bis" document, have all of the errata been considered? `Does not apply`

* **IANA** Considerations:

	* [x] Are the IANA Considerations clear and complete? Remember that IANA have to understand unambiguously what's being requested, so they can perform the required actions.
`I wonder if adding a link to the CoRE Parameters registry could help, but it looks OK to me. `
	* [x] Are all protocol extensions that the document makes associated with the appropriate reservations in IANA registries?
	* [x] Are all IANA registries referred to by their exact names (check them in to be sure)?
`The two new entries to the content format registry (51 and 52) require expert review and a request has been SENT to that list.`
	* [x] Have you checked that any registrations made by this document correctly follow the policies and procedures for the appropriate registries?
	* [x] For registrations that require expert review (policies of Expert Review or Specification Required), have you or the working group had any early review done, to make sure the requests are ready for last call?
	* [x] For any new registries that this document creates, has the working group actively chosen the allocation procedures and policies and discussed the alternatives?
`no new registries`
	* [x]  Have reasonable registry names been chosen (that will not be confused with those of other registries), and have the initial contents and valid value ranges been clearly specified?