WS-Management > Support for WS-Management in Intel AMT > Working with Intel AMT using Endpoint References (EPRs)

Working with Intel AMT using Endpoint References (EPRs)

An endpoint reference, or EPR, identifies an object based on two elements: the object type and fields that are unique in the object. The object type is contained in a resource URI which includes the class from which the object is instantiated. The unique fields are contained in a selector set. A Create or Put method returns an EPR. Creating an association requires the EPRs of the objects being associated. Performing a Get on an association returns the EPRs, which can then be used to recover the objects that the EPRs refer to.

In the following example, the actual EPR of an object is recovered, starting with the Intel AMT shortcut representation. The operation is done in three steps:

1.  First, recover an EPR from Intel AMT (for example, by performing a Get on an association object.)

2.  Next, perform a Get using the EPR from step 1 to retrieve the parameters of the object itself.

3.  Create an EPR using those fields that are key fields for the object type.

Step 1: Intel AMT returns an EPR for an instance of the class CIM_ComputerSystem:

<wsa:Address>http://10.0.0.5:16992/wsman</wsa:Address>

<wsa:ReferenceParameters>

     <wsman:ResourceURI>http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ComputerSystem</wsman:ResourceURI>

 <wsman:SelectorSet>

   <wsman:Selector Name=”CreationClassName”>CIM_ComputerSystem</wsman:Selector>

   <wsman:Selector Name="Name">ManagedSystem</wsman:Selector>

  </wsman:SelectorSet>

</wsa:ReferenceParameters>

Step 2: Given this representation, the client performs a Get on ResourceURI= http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ComputerSystem with the selectorset above, and gets the object representation itself:

<vxCoaa:CIM_ComputerSystem>

     <vxCoaa:CreationClassName>CIM_ComputerSystem</vxCoaa:CreationClassName>

     <vxCoaa:Dedicated>0</vxCoaa:Dedicated>

     <vxCoaa:ElementName>ManagedSystem</vxCoaa:ElementName>

     <vxCoaa:EnabledDefault>5</vxCoaa:EnabledDefault>

     <vxCoaa:EnabledState>2</vxCoaa:EnabledState>

     <vxCoaa:HealthState>5</vxCoaa:HealthState>

     <vxCoaa:Name>ManagedSystem</vxCoaa:Name>

     <vxCoaa:NameFormat>Other</vxCoaa:NameFormat>

     <vxCoaa:OperationalStatus>0</vxCoaa:OperationalStatus>

     <vxCoaa:RequestedState>12</vxCoaa:RequestedState>

</vxCoaa:CIM_ComputerSystem>

Step 3: Given the object representation, to retrieve its EPR use the class ResourceURI and a Selectorset. Since every CIM object is uniquely identified by the set of its key property values, create the following EPR for the above object, with the knowledge that only Name and CreationClassName are keys to CIM_ComputerSystem:

<wsa:Address> http://10.0.0.5:16992/wsman</wsa:Address>

<wsa:ReferenceParameters>

<wsman:ResourceURI>http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ComputerSystem</wsman:ResourceURI>

<wsman:SelectorSet>

        <wsman:Selector Name="Name">ManagedSystem</wsman:Selector>

        <wsman:Selector Name="CreationClassName">CIM_ComputerSystem</wsman:Selector>

</wsman:SelectorSet>

</wsa:ReferenceParameters>

The feature use cases refer to local functions GetEPR and GetObjectFromEPR. Step 2, above, is an example of what a GetObjectFromEPR function does. Step3 is an example of what a GetEPR function does.

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