This specification uses the following syntax within normative outlines:

Normative text within this specification takes precedence over normative outlines, which in turn take precedence over the XML Schema [] descriptions.

This specification uses a number of namespace prefixes throughout; they are listed in . Note that the choice of any namespace prefix is arbitrary and not semantically significant (see []).

All information items defined by this specification are identified by the XML namespace URI [] &nsuri;. A normative XML Schema [, ] document can be obtained by dereferencing the XML namespace URI.

In this document reference is made to the wsu:Id attribute in a utility schema (http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd). The wsu:Id attribute was added to the utility schema with the intent that other specifications requiring such an Id could reference it (as is done here).

It is the intent of the W3C Web Services Policy Working Group that the &framework.title; and &attachment.title; XML namespace URI will not change arbitrarily with each subsequent revision of the corresponding XML Schema documents but rather change only when a subsequent revision, published as a WD, CR or PR draft results in non-backwardly compatible changes from a previously published WD, CR or PR draft of the specification.

Under this policy, the following are examples of backwards compatible changes that would not result in assignment of a new XML namespace URI:

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [].

We introduce the following terms that are used throughout this document:

A policy is a collection of policy alternatives.

A policy alternative is a collection of policy assertions.

A policy assertion represents an individual requirement, capability, or other property of a behavior.

A policy expression is an XML Infoset representation of a policy, either in a normal form or in an equivalent compact form.

A policy subject is an entity (e.g., an endpoint, message, resource, interaction) with which a policy can be associated.

A policy scope is a collection of policy subjects to which a policy may apply.

A policy attachment is a mechanism for associating policy with one or more policy scopes.

An effective policy, for a given policy subject, is the resultant combination of relevant policies. The relevant policies are those attached to policy scopes that contain the policy subject.

The element policy is the policy attached to the policy subjects associated with the element information item that contains it.

This specification defines several mechanisms for associating policies (&framework.title;, []) with various XML Web service entities. For brevity, we define two sample policy expressions that the remainder of this document references.

The example in indicates a policy for reliable messaging []. The example in is a policy for securing messages using X509 certificates [].

The document containing both of these policy expressions is assumed to be located at http://www.example.com/policies.  Per Section 3.2 Policy Identification of &framework.title; [], the URIs used for these policy expressions in the remainder of this document are http://www.example.com/policies#RmPolicy and http://www.example.com/policies#X509EndpointPolicy, for the examples in and , respectively.

Policies will often be associated with a particular policy subject using multiple policy attachments. For example, there may be attachments at different points in a WSDL description that apply to a subject, and other attachments may be made by UDDI and other mechanisms.

When multiple attachments are made, they must be combined to ascertain the effective policy for a particular policy subject. This is done by identifying which policy scopes a particular subject is in and combining the individual policies associated with those scopes to form an effective policy.

This combination can be achieved by a merge operation. This consists of serializing each policy as a policy expression, replacing their wsp:Policy element with a wsp:All element, and placing each as children of a wrapper wsp:Policy element. The resulting policy expression is considered to represent the combined policy of all of the attachments to that subject.

Such calculated policy expressions have no meaningful URI of their own.

This section defines two general-purpose mechanisms for associating policies [] with one or more policy subjects. The first allows XML-based descriptions of resources to associate policy as part of their intrinsic definition. The second allows policies to be associated with arbitrary policy subjects independently from their definition.

It is often desirable to associate policies with the XML elements describing a subject; this allows description formats such as WSDL to be easily used with the Web Services Policy Framework (see Section for the specific details of WSDL attachment).

The precise semantics of how element policy is to be processed once discovered is domain-specific; however, implementations are likely to follow the precedent specified in the section below on WSDL [] and Policy.

This specification defines a global attribute that allows policy expressions to be attached to an arbitrary XML element. The following is the schema definition for the wsp:PolicyURIs attribute:

The namespace URI [] for this attribute is &nsuri;.

The wsp:PolicyURIs attribute contains a white space-separated list of one or more URIs []. When this attribute is used, each of the values identifies a policy expression as defined by []. If more than one URI is specified, the individual referenced policies need to be merged together to form a single element policy expression. The resultant policy is then associated with the element information item's element policy property.

Note that the policy scope of the attachment is specific to the policy attachment Mechanism using it; accordingly, any policy attachment mechanism using this attribute MUST define the policy scope of the attachment.

An example of element policy through the use of this global attribute is given below using the sample policies stated in Section .

If the policies referenced by the following XML element

have been processed and merged, it would result in an element policy whose XML 1.0 representation is listed in :

Note that this element policy has no meaningful URI.

The presence of the wsp:PolicyURIs attribute does not prohibit implementations from using additional mechanisms for associating policy expressions with XML-based constructs.

Alternatively, rather than using the global attribute, XML elements may use the wsp:Policy or wsp:PolicyReference elements directly as children, in order to support element policy, and the semantics for this are the same as for the use of the global attribute. For example, an alternative way of attaching the policies in the above example, using child elements, would be as follows: 

This mechanism allows policies to be associated with a policy subject independent of that subject's definition and/or representation through the use of a wsp:PolicyAttachment gelement.

This element has three components: the policy scope of the attachment, the policy expressions being bound, and optional security information. The policy scope of the attachment is defined using one or more extensible domain expressions that identify policy subjects, typically using URIs.

Domain expressions identify the domain of the association. That is, the set of policy subjects that will be considered for inclusion in the scope using an extensible domain expression model. Domain expressions identify policy subjects to be included within the policy scope. Domain expressions yield an unordered set of policy subjects for consideration.

For the purposes of attaching policy to a policy subject through this mechanism, any policy expression contained inside of the wsp:AppliesTo element MUST NOT be considered in scope. For example, an Endpoint Reference may be used as a domain expression, and it may contain policy expressions within it, but this policy expressions are not considered in scope with respect to the wsp:PolicyAttachment element using it.

The following is the pseudo-schema for the wsp:PolicyAttachment element:

The following describes the attributes and elements listed in the pseudo-schema outlined above:

The following example illustrates the use of this mechanism with an EndpointReference domain expression for a deployed endpoint as defined in Web Services Addressing []:

In this example, the policy expression at http://www.example.com/policies#RmPolicy applies to all interactions with the endpoint at http://www.example.com/acct.

Policy attachments in WSDL 1.1 can be used to associate policies with four different types of policy subject, identified as the service policy subject, the endpoint policy subject, the operation policy subject, and the message policy subject. These subjects should be considered as nested, due to the hierarchical nature of WSDL.

When attaching a policy to a WSDL element, a policy scope is implied for that attachment. The policy scope only contains the policy subject associated with that element and not those associated with the children of that element. Therefore, it is RECOMMENDED that each policy assertion contained within a WSDL element's element policy should have the correct semantic such that the subject for that assertion is that WSDL element. For example, assertions that describe behaviours regarding the manipulation of messages should only be contained within policies attached to WSDL message elements.

Figure 1 represents how the effective policies, with regard to WSDL, are calculated for each of these policy subjects. In the diagram, the dashed boxes represent policy scopes implied by WSDL elements. For a particular policy subject, the effective policy MUST merge the element policy of each element with a policy scope that contains the policy subject.

For abstract WSDL definitions, the element policy is considered an intrinsic part of the definition and applies to all uses of that definition. In particular, it MUST be merged into the effective policy of every implementation of that abstract WSDL definition.

Policies that are attached to a deployed resource (e.g., services or ports) are only considered in the effective policy of that deployed resource itself.

This section defines a domain expression based on Web Services Addressing [] to allow the use of the wsp:PolicyAttachment mechanism to reference a specific endpoint of a deployed Web service.

The following schema outline illustrates this extension:

An example of an Endpoint Reference is given at the end of Section to illustrate the extensibility of the wsp:AppliesTo element.

Use of this domain expression is equivalent to policy attachment to a deployed endpoint in WSDL, using the wsdl11:port element, i.e., the effective policy resulting from the combination of policies declared should be considered a part of the endpoint policy scope.

When attaching a policy to a UDDI entity a policy scope is implied for that attachment. The policy scope only contains the policy subjects associated with that entity, and not those associated with the children of that entity. This policy is the entity's element policy.

Each policy assertion contained within a UDDI entity's element policy should have the correct semantic such that the subject for that assertion is that UDDI entity. For example, assertions that describe behaviours regarding a service provider should only be contained within policies attached to a businessEntity structure.

For UDDI tModels that represent Web service types, the element policy is considered an intrinsic part of the tModel and applies to all uses of that tModel. In particular, it MUST be merged into the effective policy of every bindingTemplate that references that tModel.

Policies that apply to deployed Web services (bindingTemplates) are only considered in the effective policy of that deployed resource itself.

Each of these entities MAY have an element policy per Section . The remainder of this section defines how that element policy is interpreted to calculate the effective policy.

UDDI tModels provide a generic mechanism for associating arbitrary metadata with services and other entities in a UDDI registry. To properly integrate Web Services Policy into the UDDI model, &attachment.title; pre-defines one tModel that is used to associate a remotely accessible policy with an entity in a UDDI registry.

This new tModel is called the remote policy reference category system and is defined in Appendix .

UDDI registries MUST use the tModelKey uuid:a27078e4-fd38-320a-806f-6749e84f8005 to uniquely identify this tModel so that UDDI registry users can expect the same behavior across different UDDI registries.

The tModel's valid values are those URIs that identify external policy expressions; that is, when referencing this category system in a categoryBag, the corresponding keyValue of the keyedReference is the URI of the policy expression.

Using the remote policy reference category system, one can then associate a policy expression with a businessEntity, a businessService, and a tModel using the entity's categoryBag. For example, associating the policy expression that is identified by the URI http://www.example.com/myservice/policy with a businessService is done as follows: 

The tModelKey of the keyedReference MUST match the fixed tModelKey from the remote policy reference category system. The keyValue MUST be the URI that identifies the policy expression.

A different approach has to be taken to associate a policy expression with a bindingTemplate, since bindingTemplates do not contain a categoryBag in UDDI Version 2. Therefore, the bindingTemplate's tModelInstanceInfo and instanceParms MUST be used as follows: 

The tModelKey of the tModelInstanceInfo MUST match the fixed tModelKey from the remote policy reference category system as defined above. The instanceParms MUST be the URI that identifies the policy expression.

In addition to using the approach outlined in the section above, publishers may register a specific policy expression in a UDDI registry as a distinct tModel. To properly categorize tModels as policy expressions, &attachment.title; pre-defines the Web Services Policy Types category system as a tModel. This tModel is defined in Appendix .

The following illustrates a tModel for the policy expression identified by the URI http://www.example.com/myservice/policy.

The first keyedReference specifies that the tModel represents a policy expression — rather than only being associated with one — by using the Web Services Policy Types category system's built-in category "policy", which is its single valid value. This is necessary in order to enable UDDI inquiries for policy expressions in general. The second keyedReference designates the policy expression the tModel represents by using the approach from the section above. This is necessary in order to enable UDDI inquiries for particular policy expressions based on their URI.

Note that the policy expression URI is also specified in the tModel's overview URL to indicate that it is a resolvable URL to actually retrieve the policy expression.

&attachment.title; pre-defines another tModel that is used to associate such a pre-registered, locally available policy expressions with an entity in a UDDI registry

This new tModel is called the local policy reference category system and is defined in Appendix .

UDDI registries MUST use the tModelKey uuid:a27f7d45-ec90-31f7-a655-efe91433527c to uniquely identify this tModel so that UDDI registry users can expect the same behavior across different UDDI registries.

The local policy reference category system is based on tModelKeys. The valid values of this category system are those tModelKeys identifying tModels that

That is, when referencing this category system in a category bag, the corresponding keyValue of the keyedReference is the tModelKey of the tModel that represents the policy expression.

Given the local policy reference category system, one can then associate a policy expression tModel with a businessEntity, a businessService, and a tModel using the entity's categoryBag. For example, associating the policy expression tModel with the tModelKey "uuid:04cfa…" from above with a businessService is done as follows: 

The tModelKey of the keyedReference MUST match the fixed tModelKey from the local policy reference category system. The keyValue MUST be the tModelKey of the policy expression that is registered with the UDDI registry.

A different approach has to be taken to associate a policy expression with a bindingTemplate, since bindingTemplates do not contain a categoryBag in UDDI Version 2. Therefore, the bindingTemplate's tModelInstanceInfo and instanceParms MUST be used as follows: 

The tModelKey of the tModelInstanceInfo MUST match the fixed tModelKey from the local policy reference category system. The instanceParms MUST be the tModelKey of the policy expression that is registered with the UDDI registry.

UDDI Version 3 [] provides a number of enhancements in the areas of modeling and entity keying. Special considerations for UDDI multi-version support are outlined in chapter 10 of []. The changes with respect to the previous sections are as follows.

First, the tModelKeys of the pre-defined tModels are migrated to domain-based keys. The migration is unique since the Version 2 keys introduced in this specification are already programmatically derived from the Version 3 keys given below.

The tModelKey for the remote policy reference tModel changes from "uuid:a27078e4-fd38-320a-806f-6749e84f8005" to "uddi:schemas.xmlsoap.org:remotepolicyreference:2003_03".

The tModelKey for the Web Services Policy Types tModel changes from "uuid:fa1d77dc-edf0-3a84-a99a-5972e434e993" to "uddi:schemas.xmlsoap.org:policytypes:2003_03".

The tModelKey for the local policy reference tModel changes from "uuid:a27f7d45-ec90-31f7-a655-efe91433527c" to "uddi:schemas.xmlsoap.org:localpolicyreference:2003_03".

Second, rather than putting policy expression references in a bindingTemplate's tModelInstanceInfo, they are added to the bindingTemplate's categoryBag, analogous to the mechanism described for other UDDI entities. For example, the example bindingTemplate from section would be changed as follows: 

Third, inquiries for reusable policy expression tModels and UDDI entities that are associated with remote policy expression is enhanced by the wildcard mechanism for keyValues in keyedReferences. For example, searching for all policy expression tModels whose URI starts with http://www.example.com/, the following find_tModel API call can be used: 

Fourth, all UDDI entities may be digitally signed using XML digital signatures []. Publishers who want to digitally sign their policy expression tModels or policy expression references in UDDI MUST use the Schema-centric canonicalization algorithm [].