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Subject: [wsdm][UPlat] Definitions UPlat Items - Aggregated for easy review and accessibility
I scanned our UPlat email archives (reverse chronological) to get the latest definitions of each UPlat item from our discussions. Owners/Champions, please review and send corrections. I will be happy to coordinate the next revision of this list of definitions. Thanks ----- High: ----- * Identification: - Definition(s): Identification is a way to represent that one element is same or different than the other without necessarily looking at the contents or definition of the element. Applied to Web resources in general, as defined by W3C, a Uniform Resource Identifier (URI) can be used to represent the identity of a Web resource. Applied to Web services, every element which Web service description is composed of (service, interface, endpoint, location, etc.), is required to be identifiable by a URI. Such URI must be unique by definition. Identity is not required to be an addressable location, so a dereferencing mechanism may be required to actually locate the corresponding resource. - Management Need(s): Manageable resources need to be uniquely identified for the manager to tell one from the other and also to consistently refer to. Therefore a standard representation of a unique identity is required. * Versioning: - Definition(s): Versions: A sequence of copies of (Functional and Manageability) Webservices incorporating new modifications. Each version is identified by a number, following a certain specified format signifying the major version number and the release number. Typically an increment in the major version signifies a substantial increase in the function of the Webservice or a partial or total re-implementation. Whereas the release number increases each time the Webservice is changed in any way and re-released. Versioning information must also contain change description that describes what has changed in a revision compared to the previous one. - Management Need(s): 1. Version numbers are useful so that the manager can know if the manageable Webservice interfaces have changed (bugs have been fixed or new functions added) since she obtained her copy. She could also learn whether a bug report relates to the current version. 2. A manager of manageable resources must have the ability to query the available endpoints' revisions along with the corresponding change descriptions such that the manager can discern the most appropriate and compatible interface of a particular manageability function that her management client can use. * Attributes: - Definition(s): Schema to describe attributes of a Web service and portType operations to access and set the attributes. Attributes should be introspect-able at design time and runtime. Attribute is synonymous with property. For manageability, a property is a name, type, value triple that is part of the advertised manageability interface for a resource. An attribute can be used to represent configuration values, metrics, identifiers, etc. * Metadata: - Definition(s): Attribute Metadata - schema that defines how to describe metadata about attributes, operations, events, or interfaces of a Web service. This metadata for attributes could include includes units, volatility, modifiability. Metadata about operations may include idempotency, endState. Metadata should be introspect-able at design time and runtime. Note that metadata applies to more than just attributes. Operations and events. And interfaces. Do we need a definition of metadata? Should it include policies? WSDL documents? Is it settable? "Data about data". "Definition of data that provides information about what is being managed." Don't want to include metadata that is "related" to the data, just the metadata that is "about" the data. Or Definitional. From Dictionary.com: <data> /me't*-day`t*/, or combinations of /may'-/ or (Commonwealth) /mee'-/; /-dah`t*/ (Or "meta data") Data about data. In data processing, meta-data is definitional data that provides information about or documentation of other data managed within an application or environment. For example, meta-data would document data about data elements or attributes, (name, size, data type, etc) and data about records or data structures (length, fields, columns, etc) and data about data (where it is located, how it is associated, ownership, etc.). Meta-data may include descriptive information about the context, quality and condition, or characteristics of the data. * Addressing: - Definition(s): Addressing is the ability to reference an identified entity so that it can be accessed. In the case of a web service, "being accessed" means getting hold of its WSDL description and any extra information that might be needed to route messages to the service. Addressing is the ability to reference another entity. One examples of where a reference is required is in a relationship to refer to the entities that have an association with each other. Another example is to refer to the Web service where asynchronous notifications should be sent. In general, the Web service exposing the manageability interfaces for a resource may need a reference to the resource. Since not all resources are Web services, a reference must be defined such that non-Web service entities can also be referred to. The special case of referring to a Web service entity should refer to the WSDL for the Web service such that a manager can choose which Web service endpoint it wants to send messages. - Management Need(s): Addressing is required to provide references to other entities. Other entities may include resources, Web services, WSDL documents, policy descriptions, as well as other documents and services. Addressing defines the mechanism used to specify the reference. Management using Web services requires a standard mechanism for \ referring to other entities. * Notification: TBD * Relationship: - Definition(s): schema to describe relationships between resource types, resources, interfaces, and endpoints; including portType operations to get and modify the current set of relationships from a participant in the relationship. Static relationships and relationships between types and interfaces should be introspect-able at design time and runtime. All relationships should be introspect-able at runtime. - Management Need(s): - design vs. runtime. - "Static relationships should be introspect-able at design time." ---------------------- Medium above cut line: ---------------------- * Security: - Definition(s): Information/Computer Security. There are many ways to categorize information security, but the most common today is represented by the letters C, I, A: Confidentiality, Integrity, and Authentication. Additional concepts that can be arguably kept separate are: Access Control, Nonrepudiation, Availability, and Privacy. Confidentiality: Preventing unauthorized entities from accessing information or resources. Integrity: Making sure that when authorized entities access information, it is either not changed or any changes are detectable. Authentication: Making sure that entities are who/what they claim to be. Access Control: Making sure that entities can only access services, resources, or information that they are authorized for. Nonrepudiation: Making sure the sender of a message can not deny having sent the message. Availability: Making sure a service or resource can be accessed by authorized users. While this goes beyond security, security is expected to address denial of service attacks. Privacy: Making sure that information on entities is used only for the express purposes allowed. - Management Need(s): Resources have to be manageable in a secure way (see definition of security). Security is composable on top of the manageability exposed via Web services, similar to securing any other capability of a resource exposed via a Web service. For example, access to a manageability operation can be granted to only clients that present "manager's identity" in a request message. Security must be manageable, preferably via Web services. For example, identity or access assertion can be verified by issuing a request to a security Web service. * Registration/Discovery: - Definition(s): Registration is a method of advertising an existence of an element so that it can be discovered. Discovery is a method of locating an existing element so that it can be used or operated. Discovery can be based on a selection criteria or simply a name or identity of an element. Location is a method of obtaining an address of an element. For example, location may mean translating an identity of an element into an address of an existing useable element. In the Web services sense, registration, discovery and location can be represented by a set of operations and schema which may be implemented by a Registry. A Web service can register itself or can be registered by a third party by sending a request to the Registry. A Web service can be discovered by sending a request to the Registry. The Registry can return the description of a Web service with location address included in a description or it may return the location address directly. - Management Need(s): 1. Manageable resources have to be discoverable by the managers. 2. Manageable resources exposed via Web services can be registered, discovered and located via a Registry. * Policy: - Definition(s): 1. is a course of action, guiding principle, or procedure considered expedient, prudent, or advantageous for a given condition or event. 2. describes a broad range of service requirements, preferences, and capabilities. 3. provides a set of requirements to a manageable resources in a specific context. There are various policies that can be specified to a manageable resources (Webservice functional and manageability endpoints) via MUWS such as: authentication, access control, privacy, non- repudiation, service level agreement, quality of service, routing, content inspection, auditing, etc. policies. - Management Need(s): MUWS must leverage as much as existing Webservices specifications and technologies in applying policies to the manageable resources. MUWS should endorse a list of such specifications and technologies, and should specify the compatibility and interoperability requirements (i.e. must meet WS-I). ---- Low: ---- * Collection: - Definition(s): A collection is an entity which acts as a proxy to zero or more other entities. A manager can send a single request to a collection where the result is that zero or more members of the collection are acted upon as specified in the request. The members of a collection are managed entities in their own right and have their own management interfaces. The result of a manager sending a single request to a collection must be the same as a manager sending a separate message to each of the selected members of the collection individually. It is not necessary that the collection actually send separate messages to each of its members, only that the result to the members is the same. A collection provides a mechanism to perform the same action on many managed entities at once, and acts as one scalability mechanism in a management system. - Management Need(s): As the number of managed resources grows, it becomes more important for a management system to provide a mechanism to allow a manager to perform the same action on many resources at once. For instance, with a collection a manager can query for the state of all resources in the collection at once rather than one at a time. Also, it is possible for a collection to reset the state of metrics for the resources in the collection using a single request. A collection provides the ability for a management system to scale much better than a system not supporting collections. Also, there are cases where the exact membership of a group is better known by an entity, such as a collection, that may be closer to the group than a manager. This allows the manager to defer to the collection to determine the exact entities to act upon. * (Work)Flow: - Definition(s): the capability to describe a sequence of web services interactions, where each interaction is fully or partially determined by the sequence description and the result of previous interactions in that sequence. * Negotiation: - Definition(s): Negotiation is the act or process of arranging for or bringing about through conference, discussion, and compromise. For Web services, negotiation refers to the process of coming to agreement on the advertised aspects of a service (e.g., quality of service). - Management Need(s): Negotiation of QoS for a manageability interface seems far off in the distance from the current work of this group. * Relationship Service: - Definition(s): A relationship repository or registry which may be responsible for creating, inventorying, tracking, and validating relationships. This service is not a participant in the relationships. If relationships are rule based, then it would also be responsible for altering relationship members based on the rules. This would include portType operations for querying, adding, finding, and validating relationships. This service would build on the Relationships schema above. * Logging: - Definition(s): Logging is the action in which message producers generate log artifacts, i.e., atomic expressions of diagnostic information, that may or may not be used at a later time by other, independent, message consumers. Secure logging is required for audit trails needed to fulfill judiciary and organizational policy requirements, to reconcile security related inconsistencies, and to provide for forensic evidence both after the fact and real-time. * Policy Decision Point: - Definition(s): A program with a repository that stores and calculates various (overlapping) policies that can be applied to various (associated) manageable resources. * Policy Enforcement Point: - Definition(s): A program that enforces various set of policies on (associated) various manageable resources. ---- TBD: ---- * Lifecycle: - Definition(s): Lifecycle is a set of states that a resource can be in and the valid transitions between those states. A resource goes through a set of states and transitions throughout its life. Lifecycle provides the capability to manage the actual operational state of a resource, operations to influence a change in the state of a resources, and events indicating when a state change has occurred. An application or management tool uses the lifecycle information for a resource to better manage that resource. For example, valid operations or valid property values of a resource may be determined through introspection of a resource's state to aid the application or management tool in doing those actions only in the state in which those actions are valid. This is important in autonomic systems where actions taken do not expect exceptions to be thrown. * Name Resolution: TBD
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