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DMTF
Tutorial > WBEM > CIM-XML
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CIM-XML
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URI | XML | CIM-XML | CLP | Discovery | CQL
CIM-XML is a protocol for exchanging CIM information. CIM-XML has
the following components:
- Common Information Model (CIM)
- xmlCIM encoding
- set of operations to retrieve and manipulate CIM data
- HTTP encapsulation
CIM-XML uses xmlCIM as the payload and HTTP as the transport. CIM-XML
defines all interactions between management clients and management infrastructure as CIM messages, which are
well-defined request or response data packets
used to exchange information.
The two types of CIM Messages
are as follows:
- A CIM operation message is a CIM message that is used to invoke
an operation.
- A CIM export message is a CIM message that is used to communicate
information about a CIM namespace or element that is foreign to the
target. A CIM export message is informational only and does not
define an operation on the target CIM namespace or even imply the
existence of a target namespace.
A XML Document Type Definition (DTD) is a document that sets the rules for how the XML is structured. CIM-XML has defined the CIM-XML DTD. The XML payload of CIM messages is loosely valid.
The term loosely valid
applles to an XML Document as follows:
- If any attributes or elements in the XML document which do not
appear in the CIM XML DTD are removed, then the resulting document
is valid with respect to the CIM XML DTD.
In effect, a loosely valid document is one that is valid with
respect to the CIM XML Document Type Definition (DTD) apart from
having additional attributes or elements that are not defined in that DTD.
The concept is very similar to that of an open content model.
One corollary of this definition is that any XML
document that is valid with respect to the CIM XML DTD is also loosely
valid.
The motivation for introducing this class of XML documents is to relax
the restrictions on a CIM Client, CIM Server or CIM Listener when it is
parsing received XML documents that are defined within the scope of this mapping.
Not all CIM Clients (CIM Servers or
CIM Listeners) should be required to validate each received CIM Message
Response (CIM Message Request) because this would place too great
a processing burden on the validating entity at the expense of footprint
and performance, most notably in communication between robust and conformant
implementations of this mapping.
Instead, this specification makes the following requirements:
- A CIM Client (respectively, CIM Server or CIM Listener) may include a
DOCTYPE element in a CIM Message Request (respectively, CIM Message Response).
If so, an External declaration should be used (inclusion inline of the complete
DTD within a message is discouraged).
- A CIM Client (respectively, CIM Server or CIM Listener) may elect to
validate a received CIM Message Response (respectively, CIM Message Request).
- If a CIM Client (respectively, CIM Server or CIM Listener) elects not
to validate a received CIM Message Response (respectively, CIM Message Request),
then loose validation must be enforced.
Finally, all CIM operation requests are defined as invocations of one or more
methods. A method is either:
- Intrinsic, which means that it is defined by this specification for
the purposes of modeling a CIM operation
- Extrinsic, which means that it is defined as a method on a CIM class
in some Schema.
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