1. Summary on the M2M CMDH Policies Management Object (MCMDHMO)
Group Name: Joint call of OMA-DM WG and oneM2M MAS WG
Source: Wolfgang Granzow, Qualcomm,
Meeting Date:
Agenda Item: New OMA-DM Management Object “MCMDHMO”

2. Objective This presentation provides
background information on the use of CMDH policies in oneM2M systems not included in TS-0005 “Management Enablement”
a summary of the structure of their components which need to be mapped to the MCMDHMO tree
a summary of the MCMDHMO structure

3. oneM2M communication paradigm
All state information is kept inside service-layer entities (AEs and CSEs)
The oneM2M system employs resource-based communication where request messages exchanged between oneM2M entities trigger specific operations on instances of those standardized resources:
Create a resource
Retrieve the content of a resource (all or partially)
Update a resource
Delete a resource
Notify subscribed receivers of changes made on a resource
The operation result may then be reported with a response message by the request receiver to the request originator

4. Purpose of CMDH Policies
In the oneM2M architecture of a Common Services Entity (CSE) a function called Communication Management and Delivery Handling (CMDH) controls communications with other entities (CSEs, AEs and NSEs)
This function decides
when it is needed and allowed to buffer communication messages so that these can be forwarded at a later time
at what time to use which communication connection
The processing in the CMDH function is governed by CMDH policy parameters that can be specific to each request or response message

5. CMDH-related parameters in Requests
Request Expiration Timestamp (rqet)
the time after which a request is stale and can be purged
Result Expiration Timestamp (rset)
the time after which the result of an earlier requested operation is stale and can be purged
Event Category (ec)
a means to categorize the events that triggered a message
CMDH policies are defined per Event Category
Delivery Aggregation (da)
a boolean parameter which indicates whether or not this request message can be buffered and aggregated with others
Operation Execution Time (oet)
indicates the time when the specified operation is to be executed by the target CSE
Result Persistence (rp)
indicates the duration for which the resource containing the results is to persist
NOTE: rset and ec parameters also apply to response messages

6. Structure of CMDH Policies
Defaults: Defines which CMDH related parameters will be used by default when a request or response message contains the Event Category parameter but not any other CMDH related parameters and which default Event Category parameter shall be used when none is given in the request or response.
Limits: Defines the allowed limits for CMDH related parameters in request or response messages with a given Event Category value.
Network usage: Defines the conditions when usage of specific Underlying Networks is allowed for request or response messages with a given Event Category value.
Buffering: Defines limits of supported buffer size to be used for storing pending messages with a given Event Category value and their priorities when deletion cannot be avoided.

7. cmdhPolicy resource
consists of a name attribute and of references to following types of child resources:
cmdhDefaults, tree occurence One
cmdhLimits, tree occurence OneOrMore
cmdhNetworkAccessRules, tree occurence OneOrMore
cmdhBuffer, tree occurence OneOrMore
The references itself are denoted defaultRule, limitRules, networkAccessECRules and bufferRules in the management tree

8. cmdhDefaults resource
Divided into two type of child resources:
cmdhDefEcValue, tree occurence OneOrMore
defines a default ec value to be used when certain conditions are met (applicable if ec is not indicated in the message)
order: index indicating the order of processing of multiple cmdhDefEcValue instances
requestOrigin: a list of originator IDs that need to be matched
requestContext: e.g. battery status conditions
requestCharacteristics: parameters set in the message
requestContextNotification: indicating need for subscription
cmdhEcDefParamValues, tree occurence OneOrMore
defines default rqet, rset, oet, rp and da values to be used for specific ec
applicableEventCategories: ec values for which this set applies
defaultRequestExpTimestamp: default rqet value setting
defaultResultExpTimestamp: default rset value setting
defaultOpExecTime: default oec value setting
defaultDelAggregation: default da value setting

9. cmdhLimits resource Consists of following elements:
order, indicating order of processing of multiple cmdhLimits instances
requestOrigin, applicable request originator IDs
requestContext, applicable context info
requestContextNotification, boolean parameter indicating if this CSE needs to subscribe to dynamic context information
requestCharacteristics, applicable request parameters
limitsEventCategory, allowed ec values
limitsRequestExpTime, defines allowed range of rset parameter settings
limitsResultExpTime, defines allowed range of rqet parameter settings
limitsRespPersistence, defines allowed range of rp parameter settings
limitsDelAggregation, defines the allowed settings of the da parameter

10. cmdhNetworkAccessRules resource
Consists of following element,
applicableEventCategories, ec values for which this resource instance applies
and of references to the following type of child resource:
cmdhNwAccessRule, tree occurence ZeroOrMore

11. cmdhNwAccessRule resource
Consist of following elements:
targetNetwork: list of one or more network identifiers
minReqVolume: minimum amount of data that needs to be aggregated before the applicable network is accessed
backOffParameters: list of three time parameters that define how to proceed with further access attempts in case network access fails
otherConditions: other applicable conditions that need to matched
allowedSchedule: a list of schedule elements which define time intervals when network access is allowed

12. cmdhBuffer resource Consist of following elements:
applicableEventCategory, ec values for which this buffer limit applies
maxBufferSize, maximum memory size in bytes
storagePriority, number in range 1 to 10 which defines priority of the buffered data of the given Event Categories

13. activeCmdhPolicy resource
A managed node can have one or more sets of cmdhPolicy resources assigned as children
The activeCmdhPolicy resource is used to provide a reference to the currently active set of CMDH policies
This identifies which set of CMDH policies is currently actively in use in the corresponding CSE
This shall allow the DM technology to activate a policy set independently of the download of a new set of CMDH policies in order to avoid potential race conditions

14. Structure of the MCMDHMO (1)

15. Structure of the MCMDHMO (2)

16. Structure of the MCMDHMO (3)

17. Structure of the MCMDHMO (4)

18. Further Discussion Points
DDF generation
does an OMA-DM issued tool exist?
which DTD version shall be referred to, V1.2 or V1.3 ?