2.2.3.7 SOAP
A Simple Object Access Protocol (SOAP) [SOAP1.1] [SOAP1.2/1] [SOAP1.2/2] technical specification defines a packet-based protocols. Unlike Block technical specifications, SOAP specifies request/response, SOAP-based protocols that use Web Services Description Language (WSDL). SOAP technical specifications typically apply to Web services.
A SOAP technical specification uses the features and mechanisms defined in XML and WSDL to define the protocol as closely as those mechanisms allow. SOAP services support the feature of returning XSD and WSDL documents that describe the protocol that the service implements. If the XSD includes character data that follows a grammar that cannot be described in the XSD, the grammar can be defined in the technical specification, or a normative reference to the grammar definition is provided. If the character data has some internal syntax that is not defined in a normative reference, the syntax is specified in the technical specification by using "augmented" BNF (ABNF).
If the XSD includes binary data that follows a grammar that cannot be described in the XSD, the grammar is defined in the technical specification, or a normative reference to the grammar definition is provided. If the grammar is defined in the technical specification, the packet definition format used in Block technical specifications (section 2.2.3.2) is used.
SOAP technical specifications can contain the following types of normative information, where applicable: