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5.5 DM Server Interactions

5.5.0 Introduction

This clause describes how the IN-CSE interacts with a DM Server in order to manage the devices. To interact with the DM Server, the IN-CSE needs to establish the communication session with the DM Server, translate requests/responses and notifications between the IN-CSE and the DM Server and discover the management objects in the device and Management Resources in the IN-CSE.

Note

1: The DM Server interaction is applicable to the case that the DM Server is external to the IN-CSE. 2: OMA has started the work item called "Management Interface to M2M" [11] whose scope is to define requirements for an interface between the DM Server and the Machine to Machine (M2M) systems on top. This Northbound Interface (NBI) allows M2M service layer to access the DM Server functionality. The requirements for the interaction between the IN-CSE and the DM Server will be specified in [11].

5.5.1 Communication Session Establishment

The communication session can be initiated by the IN-CSE or by the DM Server. The IN-CSE can initiate the communication session if the IN-CSE needs to interact with the management objects in the device through the DM Server (e.g. an IN-AE sends firmware update Requests by using the [firmware] Resource in the IN-CSE). On the other hands, the DM Server can initiate the communication session if the DM Server detects changes of management objects that the DM Server manages or needs to notify events to the IN-CSE that occurred in the device. In this case, the notifications of management object changes or events can be limited to the cases that the IN-CSE has expressed interests.

The multiple communication sessions can be established between the IN-CSE and the DM Server depending on the communication environments and the protocols to be used for the communication session. The requirements for the communication session between the IN-CSE and the DM Server will be specified by [11].

Note

Both OMA DM 1.3 and DM 2.0 support the concept of the management session, but the established communication session between the IN-CSE and the DM Server does not imply the immediate management session establishment between the DM Server and the DM Client.

5.5.2 Translation of Requests and Responses between IN-CSE and DM Server

The present document specifies how oneM2M service layer protocol regarding the device management shall be mapped to OMA DM protocol. The interaction between the IN-CSE and the DM Server lies between these two protocols and the Requests/Responses from those two protocols shall be properly translated by the interactions between the IN-CSE and the DM Server. Specifications for Requests/Responses translations between the IN-CSE and the DM Server is out of scope of the present document, and the requirements for the Requests/Responses translation will be specified by [11].

5.5.3 Discovery and Subscription for management objects

Being triggered by oneM2M service layer, the interactions between the IN-CSE and the DM Server can provide the following functionalities:

  • Discovery of management objects in the devices of interest.
  • Subscription to management objects for being notified for the interested events.

With the discovery and the subscription to the management objects in the device, the IN-CSE can be capable to synchronize the <mgmtObj> Management Resources with management objects in the device.

Note that requirements for the discovery and subscription for management objects will be specified by [11].

5.5.4 Access Control Management

For a device under managements, the IN-CSE can have multiple DM Servers that can connect to the device. When receiving the oneM2M Service Layer Requests, the IN-CSE shall first authorize the Request based on the <accessControlPolicy> resource associated with the addressed <mgmtObj> resource, Then, among those DM Servers, the IN-CSE needs to select the proper DM Server that can successfully perform the received Request based on the access rights that each DM Server has. The interaction between the IN-CSE and the DM Server can be used to discover the access rights that the DM Server has. The DM Server is agnostic of the identity or roles used in the service layer.