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, [email protected]
Meeting Date: 2015-01-13
Agenda Item: New OMA-DM Management Object “MCMDHMO”
Objective
• This presentation provides
– background information on the use of CMDH
policies in oneM2M systems not included in TS0005 “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
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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:
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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
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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
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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
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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.
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cmdhPolicy resource
• consists of a name attribute and of references to
following types of child resources:
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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
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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)
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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
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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
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cmdhLimits resource
• Consists of following elements:
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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
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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
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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
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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
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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
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Structure of the MCMDHMO (1)
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Structure of the MCMDHMO (2)
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Structure of the MCMDHMO (3)
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Structure of the MCMDHMO (4)
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Further Discussion Points
• DDF generation
– does an OMA-DM issued tool exist?
– which DTD version shall be referred to, V1.2 or V1.3 ?
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