Customized Resource Types MAS Group Name: MAS + ARC + PRO WGs Source: Wolfgang Granzow, Qualcomm Inc., Meeting Date: Agenda Item: MAS Home Domain Enablement & Joint session MAS/ARC/PRO/(SEC)

Background on this contribution This contribution is related to the work in MAS WG on Home Domain Abstract Information Models (TR- 0017) and mapping these onto oneM2M resource representations However, the approach proposed in this contribution is independent of a particular application domain – It applies equally to use cases in any other domains, e.g. industrial, automotive, eHealth, smartCity, smartGrid – It also enables efficient interworking with other M2M systems such as AllJoyn, OIC, LWM2M etc. © 2014 oneM2M Partners MAS

Problem addressed Designing M2M applications for oneM2M systems or designing interworking with applications developed for another technology, essentially need to answer the question: how to map an application or device model onto the resources standardized by oneM2M – Can this be accomplished efficiently using and resources? – Should we introduce new resource types? © 2014 oneM2M Partners MAS

Proposed Solution If oneM2M systems become widely accepted and deployed, it is predictable that there will be strong demand by application developers for new application-specific resource types to be able to implement new applications efficiently Rather than trying to fulfill this demand by standardizing an ever-growing number of new resource types, it is proposed here to standardize a procedure which enables application developers to design and deploy their own customized resource types © 2014 oneM2M Partners MAS

Concept of resource type specialization The concept of “specialization” applied to resource type can be regarded as a first step towards “customized” resource types © 2014 oneM2M Partners MAS Example of “standardized” specialization: resource type definition representing a “template” for its specializations specific attributes common/universal attributes specific attributes child resource(s) by reference subscription child resource(s)

Issues with resource type specializations specializations may be regarded as a sort of customized resource types defined to meet the objective of enabling efficient interworking with legacy Device Management protocols such as BBF TR- 069, OMA-DM and LWM2M However, any such resource type specialization actually represents a oneM2M standardized (i.e. pre-defined) resource type itself – If there is a need to add a new management object, or add/change attributes of an existing specialization, it requires oneM2M standardization activity before any such new or updated management object could be deployed into a M2M system – It may even require a major SW upgrade of all deployed nodes of an M2M system to a new oneM2M-system release before it is possible to make use of new or updated resource types © 2014 oneM2M Partners MAS

Current oneM2M Approach OneM2M has focused on standardizing resource types required to enable the fundamental functions expected from a globally usable M2M system – Making oneM2M a general “operating system” for M2M services and apps Only two generic resource types have been defined which are intended to build applications upon – These are the and resource types Although building complex applications based on and resources is feasible, it quickly becomes extremely cumbersome and inefficient Using new resource types and specializations thereof, as proposed e.g. in MAS R01 (LGE) for Home Domain applications, would be one approach to derive more efficient representations of M2M nodes and applications © 2014 oneM2M Partners MAS

Suggested Approach We suggest that oneM2M defines a generic approach which enables flexible introduction of new customized resource types “on the fly” into already deployed oneM2M systems. Such dynamically defined resource types do not need to be standardized or registered system-wide – This gives M2M service providers and application developers the highest degree of flexibility to introduce new resource types oneM2M just needs to define constraints on customized resource type to enable their use in the overall system © 2014 oneM2M Partners MAS

Potential Example Resource Type Standardized “template” for custom resource types: Example custom resource type: Attributes common to Common/universal attributes custom resource-type specific attributes child resource(s) © 2014 oneM2M Partners MAS

Suggested Approach We suggest that oneM2M defines a generic approach which enables flexible introduction of new customized resource types “on the fly” into already deployed oneM2M systems. Such dynamically defined resource types do not need to be standardized or registered system-wide – This gives M2M service providers and application developers the highest degree of flexibility to introduce new resource types oneM2M just needs to define constraints on customized resource type to enable their use in the overall system © 2014 oneM2M Partners MAS

Outline how it could work The XML schema definition developed in the PRO WG for each standardized resource type essentially includes all information required to implement and handle the resource in a CSE Additionally needed might be the specification of resource- type specific procedures (if applicable) – For most resource types this however is not required and generic CRUD procedures apply – This is especially the case for and resource types © 2014 oneM2M Partners MAS

What’s needed to define a new resource type? XML Schema definition (XSD) which defines – presence and cardinality (min and max number of occurrences) of attributes – data types of each resource attribute and applicable child resource – allocation of a resource type identifier – Note: any instantiation of a resource can be validated against its XSD with respect to correct representation of any resource attribute values or of any of their sub-elements. List of common and resource-specific attributes and definition of their presence in Create and Update primitives If applicable, a description of resource type specific procedures and definitions (e.g. default behavior when optional resource attributes are not supplied) – done for each CRUD operation, in case any differences from the generic procedures apply Specification of the applicable parent and child resources of any resource type. This is specified in clause of TS The applicable child resources are also reflected in each of the resource-specific XSD Mapping between long and short names used for resource attributes and of their complex type sub-elements © 2014 oneM2M Partners MAS

Message flow for Creation of a resource of type yet unknown to the hosting CSE AECSE 1) Create request (resourceType = 10000, resourceRef = primitiveContent = {XML or JSON representation of resource attributes} 2) Download “customType.xsd” from auto-generate binding for resource class “ customType ” (root element name defined in XSD and applied in primitiveContent data) 4) response primitiveContent = {XML or JSON serialized resource representation} 3) Create an instance of the resource, e.g. denoted washer1 using the data supplied in primitiveContent. Store the instance in the local resource data base. © 2014 oneM2M Partners MAS e.g. selected from a range of resoureType IDs reserved for custom types

Description of message flow 1)Originator sends Create request for a resource type yet unknown to the receiver and indicates a reference to an XSD file – Enumerated resourceType = (example) shall trigger creation of the new resource type. – New primitive parameter “resourceRef” provides a URI/URL of the XSD – Name of resource type is defined in both the XSD and the root element of the serialized representation supplied in primitiveContent 2)Provided the CSE supports custom resource types (for the requesting originator) it downloads the XSD file from the location indicated by the resourceRef primitive parameter (using ordinary HTTP GET request) 3)The hosting CSE auto-generates binding code for the requested new resource type, validates the data supplied in primitiveContent against the XSD. Hosting CSE adds any common resource attributes which need to be created locally (e.g. resourceName, resourceID, resourceType (enumeration code), creation/expiration time, etc.), and stores the instance of the new resource type in its data base 4)Hosting CSE sends the response to the originator, indicating successful creation of the requested resource with custom resource type, the originator obtains the attributes assigned by the hosting CSE such as assigned resourceType ID and resourceID. Any future CRUD requests for this resource type will apply the assigned resource Type ID © 2014 oneM2M Partners MAS

What needs to be standardized? Definition of a range of resource type IDs reserved for custom resource types Addition of one optional parameter to request primitives, which provides the URI to the XML Schema Definition file of the custom resource Type and definition of the procedure how to deal with this XSD – This primitive parameter should be supported by any of the binding protocols (i.e. HTTP, CoAP, MQTT and WebSockets) Addition of a general description of custom resource types to clause 9.6 of TS-0001, similarly to the section which describes the attribute (and clause 7.3 of TS-0004) Addition of a generic procedure for CRUD operations on custom resource types to clause 10.2 of TS-0001 (and clause 7.3 of TS-0004) Definition of the applicable parent resources of customized resources Possibly minor updates of resource discovery and subscription procedures to enable discovery of and subscription to custom resource types Specification of error handling (e.g. additional response status codes) for entities not supporting custom resource types Possibly addition of an informative Annex to TS-0004 which could define design guidelines for custom resource types and outline potential example implementation(s) © 2014 oneM2M Partners MAS

Trusted Web Server: XSD repository code generator CSE code CSE code development platform M2M Device Target HW Trusted Web Server: Custom XSD repository code generator CSE code M2M Device AE code M2M Device other CSEs  Use of XSD for customized resource types: Possible use of XSD (examples)  Current use of XSD for standardized resource types: © 2014 oneM2M Partners MAS

Proposal We suggest to discuss the proposed concept in MAS, ARC, and PRO WGs – There are also some SEC aspects related to secure handling of the XSD If it can be agreed to spend more work into this, we should decide under which WI it primarily should be performed and which WG should have primary responsibility. Candidates include the following: – WI Home Domain Enablement (MAS) – WI oneM2M and AllJoyn Interworking (ARC) – WI Release 2 Small Technical Enhancements (ARC + PRO) © 2014 oneM2M Partners MAS