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.

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.

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.

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.

In terms of WCF, What is a message?

A message is a self-contained unit of data that may consist of several parts, including a body and headers.

What is a service contract ( In WCF) ?

In every service oriented architecture, services share schemas and contracts, not classes and types. What this means is that you don't share class definitions neither any implementation details about your service to consumers.

Everything your consumer has to know is your service interface, and how to talk to it. In order to know this, both parts (service and consumer) have to share something that is called a Contract.

In WCF, there are 3 kinds of contracts: Service Contract, Data Contract and Message Contract.

A Service Contract describes what the service can do. It defines some properties about the service, and a set of actions called Operation Contracts. Operation Contracts are equivalent to web methods in ASMX technology

Windows Communication Framework Interview Question

· What is .NET Framework 3?
· What is Windows CardSpace ?
· What is WCF?
· What are the important principles of SOA (Service oriented Architecture)?
· What are end points, contract, address and bindings?
· Which specifications does WCF follow?
· What are the main components of WCF?
· What are different bindings supported by WCF?
· Which are the various programming approaches for WCF?
· What is one way operation?
· Can you explain duplex contracts in WCF?
· How can we host a service on two different protocols on a single server?
· How can we use MSMQ bindings in WCF?
· Can you explain transactions in WCF?
· Can you explain how End points, Contract, Address and Bindings are done in WCF?
· What is a service class?
· What is a service contract, operation contract and Data Contract?
· What are the various ways of hosting a WCF service?
· How do we host a WCF service in IIS?
· What are the advantages of hosting WCF Services in IIS as compared to self hosting?
· What are the major differences between services and Web services?
· What is the difference WCF and Web services?
· What different transaction isolation levels provided in WCF?
· Can we do transactions using MSMQ?
· Can we have two way communications in MSMQ?
· Explain Volatile queues, Dead letter queues & poison message?