Re: [core] YANG to CBOR mapping

[Ladislav Lhotka <[e-mail]>]

> On 19 Nov 2015, at 11:00, peter van der Stok <[e-mail]> wrote:
> 
> Hi CoOL authors.
> 
> I have looked at your section 5, and see an enormous overlap with the CoMI section 6. Actually the two proposals are almost completely interoperable, with a few exceptions. Much of the CoMI proposal is based on the work of Ladislav Lhotka, described in draft-ietf-netmod-yang-json. CoMI refers to this draft and uses it extensively. In the CoOL draft the yang-json draft is ignored. That is a pity because you are redoing much of the work already done in the yang-json draft. In the CoMI draft we used the results of yang-json draft, exchanged the YANG name by the hash value, and passed it through the diagnostic JSON to CBOR translator. Quite a satisfactory and elegant solution.
> Below, I have summarized my comparison between CoMI YANG to CBOR and CoOL YANG to CBOR. Please check for omissions and mistakes.
> Differences concern Binary byte string and Bits. The CoMI choice of CBOR type is derived from yang-json, and I should like to hear the opinion of Ladislav on this aspect.

Isn't it just an error? The CoOL draft says:

   Leafs of type binary MUST be encoded using a CBOR byte string data
   item (major type 0).

However, RFC 7049 defines major type 0 as unsigned integer.

> Other differences concern decimal64, and int; but I expect that is an oversight in the CoOL draft.
> A major difference is the encoding of lists and list instances; I discuss that in a separate e_mail.
> Given the overlap of work and the need for the expertise of the netmod WG, I recommend that a YANG CBOR draft is submitted to the netmod wg and uses as much as possible the contents of yang-json draft. Alternatively, I can imagine that CBOR mapping is added to the yang-json draft if the author, Ladislav Lhotka, and the WGs agree with that.

As Juergen wrote in his reply, there are good reasons not to do that.

Lada

> 
> Greetings,
> 
> Peter
> ______________________________________________________________________________
> Comparison of draft veillette-core cool, denoted with CoOL
> With draft vanderstok-core-comi, denoted with CoMI
> And draft ietf-netmod-yang-json, denoted with yang-json
> Simple YANG type can be :
> Binary byte string:                   CoMI, major type 2;                         CoOL,  major type 0
> Bits:                                 CoMI, array of text;                        CoOL, major type 0
> Boolean:                              CoMI, major type 7 (20,21);                 CoOL, major type 7 (20,21)
> decimal64:                            CoMI, major type 0 (pos) and 1(neg);        CoOL major type 0
> empty:                                CoMI major type 7(22);                      CoOL major type 7(22)
> enumeration:                          CoMI, major type 0;                         CoOL major type 0
> identityref:                         CoMI, major type 3;                          CoOL major type 3
> int8, int16, int32, int64:           CoMI, major type 0 (pos) and 1(neg);         CoOL major type 0
> leafref:                             CoMI, follows leaf type;                     CoOL follows leaf type
> string:                              CoMI, major type 3,                          CoOL major type 3
> uint8, uint16, uint32, uint64:       CoMI, major type 0;                          CoOL major type 0
> 
> In netmod-yang-json draft  JSON objects are used:
> JSON object := { name: JSON object}, where name is a string. For CoMI and CoOL the name can be an integer which is valid for diagnostic JSON used for CBOR, giving:
> CBOR object := {integer: CBOR object}
> 
> Leaf:
> Yang-json,  Name : value, where name is the string identifier of the leaf, and value of Simple YANG type
> CoMI: major type 5 containing: uint64, value;      CoOL: not defined
> 
> Union:
> Yang-json,  use corresponding media type for type of value
> CoMI, use corresponding CBOR type; CoOL, use corresponding CBOR type
> 
> anyxml,
> YANG-json, value can be of any type.
> CoMI, not applicable; CoOL, can be any CBOR type
> 
> Anydate,
> Yang-json, follows container
> CoMI, not applicable,                           CoOL, not applicable
> 
> container,
> yang-json,	 name:  JSON object
> CoMI: major type 5;                             CoOL, major type 5
> 
> leaf-list
> yang-json, name: [ value 1, value 2,……]
> CoMI, major type 4,                             CoOL, major type 4
> 
> List
> Yang-json, name:[ JSON object1, JSON object2, ….]
> CoMI, major type 5 of major type 5,             CoOL, major type 4 of major type 5
> 
> 
> 
> -- 
> Peter van der Stok
> vanderstok consultancy
> mailto: [e-mail]
> 

--
Ladislav Lhotka, CZ.NIC Labs
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