SQL Server 2005 native XML web services are based on the following open standards :
Hypertext Transfer Protocol (HTTP)
A platform-independent protocol for exchanging data. HTTP is the underlying protocol for the Web. HTTP defines the format for messages, how they are transmitted, and the actions that web servers and browsers should take in response to the message commands.
Native HTTP support in SQL Server 2005 requires the kernel-mode HTTP listener (http.sys), which is available only in Windows Server 2003 or Windows XP SP2 or later. The HTTP Configuration Utility (httpcfg.exe) is used to configure http.sys.
Simple Object Access Protocol (SOAP)
A lightweight XML-based messaging protocol used to encode web service request and response information and transmit that information over a network. SOAP is platform- and operating system-independent and can be transported over a variety of Internet protocols, including HTTP, TCP, and SMTP.
Web Service Description Language (WSDL)
An XML document format that describes the capabilities of a web service.