wcf?

Windows Communication Foundation
is a .NET library for developing and deploying services on Windows.
itF provides a runtime environment for services, enabling you to expose CLR types as services, and to consume other services as CLR types.

WCF reased with .NET 3.5

Contracts

Service contracts map to WSDL

Data contracts map to XSD

Message contracts map to SOAP

Message objects are essentially .NET representations of a
SOAP message. Format of the message will be SOAP 1.1/1.2/ Message
Transmission Optimization Mechanism (MTOM) according to the binding
configuration.

Messages travel in

•  (Hypertext Transfer Protocol [HTTP]
• Transmission Control Protocol [TCP]
• named pipes
• Microsoft Message Queuing [MSMQ])

Servicecontract attribute properties

• Name
• Namespace 
• CallbackContract  ProtectionLevel 
• ConfigurationName 
• SessionMode