How will Windows Communication Foundation change the way developers build applications?

Windows Communication Foundation radically simplifies development of distributed applications in several ways. First, Windows Communication Foundation reduces complexity by unifying the silos that exist with today's distributed technology stacks (Enterprise Services, System.Messaging, .NET Remoting, ASMX, and WSE). This enables developers to compose distributed applications using the best features of each of today's stacks. Second, Windows Communication Foundation maximizes developer productivity through an attribute-based programming model. Finally, Windows Communication Foundation is the first development framework built from the ground up on the principle of service-orientation—enabling developers to build loosely coupled applications that interoperate securely and reliably across platforms.

What is Windows Communication Foundation?

Windows Communication Foundation is Microsoft's unified programming model for building service-oriented applications with managed code. It extends the .NET Framework to enable developers to build secure and reliable transacted Web services that integrate across platforms and interoperate with existing investments. Windows Communication Foundation combines and extends the capabilities of existing Microsoft distributed systems technologies, including Enterprise Services, System.Messaging, Microsoft .NET Remoting, ASMX, and WSE to deliver a unified development experience across multiple axes, including distance (cross-process, cross-machine, cross-subnet, cross-intranet, cross-Internet), topologies (farms, fire-walled, content-routed, dynamic), hosts (ASP.NET, EXE, Windows Presentation Foundation, Windows Forms, NT Service, COM+), protocols (TCP, HTTP, cross-process, custom), and security models (SAML, Kerberos, X509, username/password, custom).

What is Service-Orientation and how is it related to Windows Communication Foundation?

Service Orientation is a specific set of architectural principles for building loosely coupled services that help developers maximize the return on your application investments over time. The services have explicit boundaries, are autonomous, share schema and contracts, and determine compatibility based on policy. Applications based on these principles provide benefits in maintainability, reusability, and manageability of connected systems. Windows Communication Foundation is the first programming model built from the ground up for building service-oriented applications.

Why is service orientation important?

Loosely-coupled applications built on the tenets of service orientation yield benefits in maintainability, reusability, and manageability of connected systems. Service-oriented applications also more closely reflect real-world processes and relationships. Microsoft sees service orientation as a means to an end—that end being a set of connected systems that optimize communications across a business—connecting people, information, and devices.

Does service-oriented development conflict with object-oriented development?

No. Service-oriented development complements object-oriented (OO) development. Object-oriented development continues to fulfill an important role in the internal design of services. Service-orientation deals with how to interconnect services to build connected systems. To use an architecture analogy, OO development addresses the architecture within a single building (a service), while service-orientation addresses the issues around city planning (a system).

How will Windows Communication Foundation make service-oriented development easier?

Today, it is difficult to build service-oriented applications due to the lack of an intuitive service-oriented programming model. Web services provide a great start, but lack support for more advanced communication, including secure and reliable transacted services. Windows Communication Foundation provides both an intuitive service-oriented programming model and the advanced functionality to create service-oriented applications that interoperate across organizational and platform boundaries.

Will Windows Communication Foundation applications interoperate with Web services built with other technologies?

Yes. By default, services built with Windows Communication Foundation will communicate with other services based on the interoperable Web services specifications. This means that Windows Communication Foundation services will communicate with any application built on an infrastructure that also conforms to these standards. Microsoft is deeply committed to platform interoperability and is an active member of key standards organizations defining the latest Web services standards. Microsoft also continues to engage in public interoperability workshops to help ensure cross-platform communication with other vendors.

What specifications will Windows Communication Foundation support?

Windows Communication Foundation will support a broad range of Web services standards, including basic standards (XML, XSD, XPath, SOAP, WSDL) and advanced standards and specifications that comprise the WS-* architecture. These include WS-Addressing, WS-Policy, WS-Security, WS-Trust, WS-SecureConversation, WS-ReliableMessaging, WS-AtomicTransaction, WS-Coordination, WS-Policy, and MTOM.

What are activities in WWF?

Activities are the elemental unit of a workflow. They are added to a workflow programmatically in a manner similar to adding XML DOM child nodes to a root node. When all the activities in a given flow path are finished running, the workflow instance is completed.

An activity can perform a single action, such as writing a value to a database, or it can be a composite activity and consist of a set of activities. Activities have two types of behavior: runtime and design time. The runtime behavior specifies the actions upon execution. The design time behavior controls the appearance of the activity and its interaction while being displayed within the designer.

What is password fatigue?

As the use of internet increases, as increases the danger of online identity theft, fraud, and privacy. Users must track a growing number of accounts and passwords. This burden results in "password fatigue," and that results in less secure practices, such as reusing the same account names and passwords at many sites.

In Terms of WCF, what do you understand by metadata of a service?

The metadata of a service describes the characteristics of the service that an external entity needs to understand to communicate with the service. Metadata can be consumed by the Service Model Metadata Utility Tool ( Svcutil.exe) to generate a WCF client and accompanying configuration that a client application can use to interact with the service.

The metadata exposed by the service includes XML schema documents, which define the data contract of the service, and WSDL documents, which describe the methods of the service.

What is a fault contract?

A fault contract can be associated with a service operation to denote errors that can be returned to the caller. An operation can have zero or more faults associated with it. These errors are SOAP faults that are modeled as exceptions in the programming model.

What is a message contract?

A message contact describes the format of a message. For example, it declares whether message elements should go in headers versus the body, what level of security should be applied to what elements of the message, and so on.

What is an operation contract?

An operation contract defines the parameters and return type of an operation. When creating an interface that defines the service contract, you signify an operation contract by applying the OperationContractAttribute attribute to each method definition that is part of the contract. The operations can be modeled as taking a single message and returning a single message, or as taking a set of types and returning a type. In the latter case, the system will determine the format for the messages that need to be exchanged for that operation.

In terms of WCF, What is binding?

A binding defines how an endpoint communicates to the world. It is constructed of a set of components called binding elements that "stack" one on top of the other to create the communication infrastructure. At the very least, a binding defines the transport (such as HTTP or TCP) and the encoding being used (such as text or binary). A binding can contain binding elements that specify details like the security mechanisms used to secure messages, or the message pattern used by an endpoint.

In terms of WCF, What is an address?

An address specifies the location where messages are received. It is specified as a Uniform Resource Identifier (URI). The schema part of the URI names the transport mechanism to be used to reach the address, such as "HTTP" and "TCP", and the hierarchical part of the URI contains a unique location whose format is dependent on the transport mechanism.

In terms of WCF, What is an infrastructure endpoint?

An endpoint that is exposed by the infrastructure to facilitate functionality that is needed or provided by the service that does not relate to a service contract. For example, a service might have an infrastructure endpoint that provides metadata information.

In terms of WCF, What is an application endpoint?

An endpoint exposed by the application and that corresponds to a service contract implemented by the application.

In terms of WCF, What is an endpoint?

An endpoint is a construct at which messages are sent or received (or both). It comprises a location (an address) that defines where messages can be sent, a specification of the communication mechanism (a binding) that described how messages should be sent, and a definition for a set of messages that can be sent or received (or both) at that location (a service contract) that describes what message can be sent.

An WCF service is exposed to the world as a collection of endpoints.

In terms of WCF, What is a service?

A service is a construct that exposes one or more endpoints, with each endpoint exposing one or more service operations.