.3.5 The Manageable and Secure Service Model
The Management model focuses on the concepts necessary to capture the notions of a manageable Web service and a secure Web service. A manageable Web service is one that can be monitored and controled (or that has manageability capabilities), adheres to management policies such as Quality of Service (QoS), and has well defined semantics for both (management semantics). A secure Web service is one that both adheres to its security policy (a statement of its security requirements also called is Qulaity of Protection (QoP)) when interacting as a provider with other service and has well defined security semantics.
The model presents two additional concepts: a manageable service and a secure service. The central idea in this model is that managing and securing a Web service is different to using a Web service. Thus a service can be made manageable by exposing manageability capabilities (control and monitoring capbilities) via a manageability interface for the service and by including additional manageability specific sematics with the service. Thus, the manageable service is itself a Web service and adheres to the Service model. The manageable service can be further augmented with management policies including advertised QoS. A service can be made secure by providing its sercurity requirements or QoP via a security policy to which the service and consumers of the service are required to adhere.
It should be noted that, although the management of the infrastructure, agents and documents needed to realize a Web service are important in order to construct large-scale Web services, their management is not considered here. The primary reason for that is that these all concern matters that are "behind" the interface; and are therefore not directly related to interoperability issues.
What is an interoperability concern is the ability of trusted partners to manage Web services as it relates to issues such as requesting particular levels of Quality of Service,adhering to management policies, and monitoring and controlling services.
The concepts and relationships in the management model are illustrated in the figure:
2.3.5.1 Manageable Service
2.3.5.1.1 Definition
A Web service becomes a manageable service with additional semantics, policy statements, and monitoring and control (or manageability) capabilities (exposed via a manageability interface) all for the purposes of managing the service.
2.3.5.1.2 Relationships to other elements
A Manageable Service is
a service
A Manageable Service has
Management Semantics
A Manageable Service has
Manageability Capabilities
A Manageable Service is associated with and accepts the obligations of
A management policy
A Manageable Service has
A manageability interface
2.3.5.1.3 Explanation
A Manageable Service is the addition of well defined management specific capabilities, requirements which are permissions, and advertised behaviors (QoS) which are obligations that augment a Web service soley for the purposes of management of that service.
2.3.5.2 Manageability Capabilities
2.3.5.2.1 Definition
Manageability capabilities are the capabilities that a Web service has for the purposes of controlling or monitoring the service that can be exposed to a management system for the sole purpose of managing the service. Manageability capabilities are distinct from the business capabilities of a service. Manageability capabilities adhere to the service model.
2.3.5.2.2 Relationships to other elements
Manageability Capabilities are
Capabilities for the purpose of managing a service
Manageability Capabilities have
An manageability information model
Manageability Capabilities are exposed
Via a manageability interface
Manageability Capabilities have
management semantics
Manageability Capabilities can be restricted
in a management policy statement
2.3.5.2.3 Explanation
Manageability Capabilities are additional capabilities exposed by a service for the purposes of making that service manageable. Manageability capabilities are themselves exposed as a service. The addition of Manageability capabilities to a service necessitates the distinction between the functionality of the service (or functional interface) and the manageable portion of the service (the manageability interface and any management policy). Thus the manageable portion of a service is soley for the purpose of managing the functionality of the service.
The existence of these capabilities implies that a manageability information model has been associated with a service and that the instantiation of the model is available during the deployment lifetime of the service
In order that a service is manageable, it must provide manageability capabilities as a service.
2.3.2.12 Management semantics
2.3.2.12.1 Definition
The management semantics of a service augments the semantics of a service with management specific semantics. This management semantics are the contract between the service providerand the service requesterthat expresses the effects and requirements pertaining to the manageability and management policies for a service.
2.3.2.12.2 Relationships to other elements
a management semantics is
the contract between the service providerand the service requesterexpresses the effects and requirements pertaining to the manageability and management policies for a service.
a management semantics is about
the manageabilitycapabilities and management policies for a service.
a management semantics describes
the intended effects of using the manageability interface for the service.
a management semantics is describes
the relationship between the service providerand the service requesterwith respect to quality of service and other management related obligations.
a management semantics describes
the relationship between the service providerand a management system as a service requestor for manageability capabilities.
2.3.???? Explanation
The management semantics includes both the effects and requirements associated with the use of the manageability interface, by a management system, as well as the meaning of the obligations that service provider maintains with the service consumer.
Management semantics augment the service semantics for a service.
So why didn't the service semantics apply to the requirements and obligations that associated with using the service. I think that this is missing from the service model and is forcing me to dance around a bit in this section.
2.3.5.3 Manageability Interface
2.3.5.3.1 Definition
The manageability interface is the interface through which the manageability capabilities of a service are exposed.
2.3.5.3.2 Relationships to other elements
A manageability interface is
A service interface
2.3.5.3.3 Explanation
A manageability interface defines the set of messages that a service recieves and sends pertaining to its manageability capabilities.
2.3.5.4 Management Policy
2.3.5.4.1 Definition
A management policy is the policy associated with Web service soley for the purpose of describing the management obligations and permissions for the service.
2.3.5.4.2 Relationships to other elements
A management policy is
A policy
A management policy describes
Obligation and permissions
A management policy describes
Quality of Service obligations
2.3.5.4.3 Explanation
A management service is a Web service that is associated with a managed service. As with other services, it is realized by an agent and is provided by a Web service provider. The latter being a person or organization.
The key property of management services is that they enable the associated managed service(s) to be controlled in some way. There are many potential forms of this control, however, in this model, these controls relate to various meta-level characteristics of the managed service: such as Quality of Service, availability, and so on. These characteristics are captured as policy obligations, which themselves may be expressed in policy documents.
Since the management service is itself a Web service it is also realized by an agent. However, there is no requirement or assumption that the management service relating to a given managed service is realized by the same agent. In fact, there may be cases where that is not possible or desirable. The management service's primary role is to realize the manageability obligations accepts by the managed service's provider.
2.3.5.5 Quality of Service
2.3.5.5.1 Definition
Quality of Service is an obligation accepted and advertised by a service producer to service consumers.
2.3.5.5.2 Relationships to other elements
Quality of Service is
An obligation
Quality of Service is
a kind of policy
Quality of Service is
an obligation that may be accepted by the provider of the managed service and being provided to the consumer of a service; allowing (or disallowing) trusted partners (i.e., a management system) to manage the quality of service associated with the service.
2.3.5.5.3 Explanation
Quality of Service may be advertised and provided by a manageable service. Quality of Service can be monitored and controled by a management system but is an obligation rather than a permission that is enforced.
This architecture does not attempt to define Quality of Service. However, many services may be associated with a level of service - sometimes numerically expressed as in available bandwidth, sometimes logically, as in encrypted versus unencrypted handling.