Re: [core] ? WG adoption of draft-veillette-core-yang-cbor-mapping-00

[Juergen Schoenwaelder <[e-mail]>]

Hannes,

whether this YANG fragment makes sense or not I simply do not know
without knowing LWM2M and since there are no open specs there is
little help you can expect. I have no clue about the interaction model
of OMA LWM2M nor do I know what LWM2M_Device is etc.

The claim was made that there is a 'simple' conversion (and I read
that as 'simple algorithm' to do conversion) and all I am asking is
whether someone actually went through the details of this. All I saw
so far are sketches of examples, thats good for a start but still
likely a longer way from a 'simple algorithm' (if that was the
intention).

But we should really be using a different thread - or simply wait
until someone managed to work out the details and got permission from
OMA to write it down without violating their legal constraints they
put on their registration wall.

/js

On Mon, Apr 25, 2016 at 12:19:54PM +0200, Hannes Tschofenig wrote:
> Hi Juergen, Hi Carsten,
> 
> The data modelling language used by OMA LWM2M is an XML schema and the
> OMA only uses it for two purposes:
> 
>  * Adding new objects and resources to the registry allows automatic
> validation (of the XML instance documents against the XML schema).
> 
>  * The XML schema really only models the data and does not attempt to
> describe the interaction.
> 
> There has been no attempt to generate code from the XML instance
> documents (as far as I know).
> 
> I have tried to take a subset of the device object and to describe it in
> Yang. To my knowledge nobody has tried to describe all currently
> registered objects with Yang.
> 
> In any case, here is what I have tried:
> 
> ----
> 
> module LWM2M_Device {
> 	// header information
> 	yang-version "1";
> 	namespace "foobar1";			
> 	prefix "LWM2M_Device";
> 	
> 	// linkage statements
> 	import extensions {
> 		prefix extensions;
> 		[e-mail];
> 	}
> 	
> 	// meta information
> 	organization "OMA";
> 	contact "foobar2";
> 	description
> 		"This object provides a range of device related information which can
> be queried by the LWM2M Server, and a device reboot and factory reset
> function.";
> 	reference
> "http://technical.openmobilealliance.org/tech/profiles/LWM2M_Device-v1_0.xml";
> 	
> 	// revision history
> 	revision 2016-04-20 {
> 		description "Initial revision.";
> 		reference "";
> 	}
> 	
> 	// module definitions
> 	extensions:LWM2M_Object_ID "3";
> 	
> 	// typedef statements
> 	
> 	// data statements
> 	
> 	leaf Manufacturer {
> 		extensions:LWM2M_Resource_ID "0";
>         type string;
> 		config true;
> 		description "Human readable manufacturer name";
> 	}
> 	
> 	leaf ModelNumber {
> 		extensions:LWM2M_Resource_ID "1";
> 		type String;
> 		config true;
> 		description "A model identifier
>                 (manufacturer specified string).";
> 	}
> 	
> 	leaf SerialNumber {
> 		extensions:LWM2M_Resource_ID "2";
> 		type String;
> 		config true;
> 		description "Serial Number.";
> 	}
> 	
> 	leaf AvailablePowerSources {
> 		extensions:LWM2M_Resource_ID "6";
> 		type int32 {
>                   range "0..7";
>                 };		
> 		config true;
> 		description "
>  0 – DC power
>  1 – Internal Battery
>  2 – External Battery
>  4 – Power over Ethernet
>  5 – USB
>  6 – AC (Mains) power
>  7 – Solar";
> 	}
> 	
> 	leaf BatteryLevel {
> 		extensions:LWM2M_Resource_ID "9";
> 		type int32 {
>             range "0..100";
>         };
> 		units percent;
> 		config false;
> 		description "Contains the current battery level as a percentage (with
> a range from 0 to 100). This value is only valid when the value of
> Available Power Sources Resource is 1.";
> 	}
> 	
> 	leaf MemoryFree {
> 		extensions:LWM2M_Resource_ID "10";
> 		type int32;
> 		units KB;
> 		config false;
> 		description "Estimated current available amount of storage space which
> can store data and software in the LWM2M Device (expressed in kilobytes).";
> 	}
> 	
> 	leaf CurrentTime {
> 		extensions:LWM2M_Resource_ID "13";
> 		type timestamp;
> 		units KB;
> 		config false;
> 		description "Current UNIX time of the LWM2M Client. The LWM2M Client
> should be responsible to increase this time value as every second
> elapses. The LWM2M Server is able to write this Resource to make the
> LWM2M Client synchronized with the LWM2M Server.";
> 	}
> 	
> }
> 
> ----
> 
> The problem I have is to find out whether Yang is able to also describe
> the interaction model of OMA LWM2M. I believe the current understanding
> is that this is not possible without some extensions. Please correct me.
> 
> Ciao
> Hannes
> 
> 
> On 04/24/2016 09:28 PM, Carsten Bormann wrote:
> > Hi Juergen,
> > 
> > trying to read your message -- are you just commenting on the side
> > conversation here or is this also a comment on the adoption call?
> > 
> > Grüße, Carsten
> > 
> > 
> > Juergen Schoenwaelder wrote:
> >> On Thu, Apr 21, 2016 at 05:34:50PM +0000, Michel Veillette wrote:
> >>> First, LWM2M have its own modeling language encoded in xml.
> >>> A file like "OMA-SUP-XML_LWM2M_Security-V1_0-20131210-C" is not fundamentally different than something than can be named security.yang.
> >>> A simple xml transform can probably do the conversion between the two without any lost.
> >>> LWM2M just have a simpler (subset) modeling language.
> >>>
> >>
> >> These are pretty bold statements. Claiming something is simple and
> >> knowing something is simple are sometimes different things. Have you
> >> worked throught the details? Is there a decent public definition of
> >> the 'simpler (subset) modeling language'? And with public I mean
> >> public, not hidden behind all sorts of registration walls.
> >>
> >> /js
> >>
> > 
> > _______________________________________________
> > core mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/core
> > 
> 



-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <http://www.jacobs-university.de/>