1. CMDH Refinement Contribution: oneM2M-ARC-0397
Source: Josef Blanz, Qualcomm UK,
Meeting Date: ARC 6.7,
Agenda Item: CSF definitions

2. CMDH: Refined Description
Description of what CMDH is supposed to do
Starts with simple UPDATE example
Proposes Stage-2 message flow
Does not cover protocol specific features (to discussed in WG3)

3. Access to local resource
AE1 trying to access local resource: For instance an UPDATE to local resource
Assumes that resource is hosted on CSE1
Request can be processed without help of other CSEs
No need to involve CMDH on CSE1 or any other CSEs Y2
Infrastructure Node
Middle Node
Application Service Node
AE1
CSE2
CSE3 Y1
CSE1 X
CMDH
UPDATE

4. Access to remote resource (1)
AE1 trying to access remote resource: For instance an UPDATE to remote resource
Assumes resource is hosted on CSE3, connectivity for Y1/Y2 may be off-line
Request may contain preferences indicating ‘lifespan’, ‘event category’ etc.
CSE1, CSE2 and CSE3 need to get involved
Multiple steps needed… see following slides
Infrastructure Node
Middle Node
Application Service Node
AE1
CSE2
CSE3
CSE1 X
CMDH
UPDATE Y1 Y2

5. Access to remote resource (2)
AE1 making request to local CSE (=CSE1),
CSE1 checks request and accepts it (other CSFs involved)
Request is targeting another CSE (=CSE3)
CMDH on CSE1 takes responsibility to deliver it
Infrastructure Node
Middle Node
Application Service Node
AE1
CSE2
CSE3
CSE1 X
CMDH
CSE1 accepts request
CMDH on CSE1 responsible
to deliver Y1 Y2

6. Access to remote resource (3)
CMDH on CSE1 is forwarding request to CSE2
CMDH on CSE1 waits until it is OK to connect to CSE2 (policies: when/how)
CSE2 checks request and accepts it (other CSFs involved)
Request is targeting another CSE (=CSE3)
CMDH on CSE2 to takes responsibility to deliver it
Infrastructure Node
Middle Node
Application Service Node
AE1
CSE2
CSE3
CSE1 X
CMDH
CMDH on CSE2 responsible
to deliver
CSE2 accepts request
CSE1 establishes connection to CSE2 Y1 Y2

7. Access to remote resource (4)
CMDH on CSE2 is forwarding request to CSE3
CMDH on CSE2 waits until it is OK to connect to CSE3 (policies: when/how)
CSE3 checks request and accepts it (other CSFs involved)
Request is targeting local CSE (=CSE3)
Local CSE3 executes original request (UPDATE)
Infrastructure Node
Middle Node
Application Service Node
AE1
CSE2
CSE3
CSE1 X
CMDH
CSE3 executes
UPDATE
CSE3 accepts request
CSE2 establishes connection to CSE3 Y1 Y2

8. Message Flow: Example Assumptions: Originator is AE1
Original request is an ‘UPDATE’ to a remote resource on CSE3
‘UPDATE’ options selected such that no feedback from update operation was requested, i.e. AE decided that it does not need to hear back from CSE3
Delivery related parameters (to be discussed separately):
Lifespan
Event Category

9. Resource Based DH
Requesting a CSE to ‘deliver’ something could be done via a resource based service
A CSE receiving such requests may have a simple path for that, e.g. /{CSE-base}/dh
A special resource type <deliveryRequest> could be defined to capture the relevant data and meta-data for delivery requests
Possible actions:
Request to Deliver something CREATE(/{CSE-base}/dh, delivReqData, lifespan, eventCat, options) or CREATE(/{CSE-base}/dh/{pref-ID}, delivReqData, lifespan, eventCat, options) => If accepted, CSE responds with actual dhr-ID (possibly more data, depends on selected options) and executes on the delivery
Request to retrieve status of delivery request RETRIEVE(/{CSE-base}/dh/{dhr-ID})
Request to change delivery parameters UPDATE(/{CSE-base}/dh/{dhr-ID}/lifespan, newLifespanValue, options)
Request to delete / cancel a delivery request DELETE(/{CSE-base}/dh/{dhr-ID}, options)
Delivery of data can be offered as a resource-based service in a RESTful manner

10. Message Flow (Resources)
Assumptions:
Originator is AE1
Original request is an ‘UPDATE’ to a remote resource on CSE3
‘UPDATE’ options selected such that no feedback from update operation was requested, i.e. AE decided that it does not need to hear back from CSE3
Delivery related parameters (to be discussed separately):
Lifespan
Event Category