Fast Web Services is the term applied to the use of ASN.1 to provide message exchanges based on a SOAP envelope and WSDL specification of services that can have a higher transaction-processing rate and less bandwidth requirements than use of a character-based XML representation.
ITU-T X.694 | ISO/IEC 8825-5 "Mapping W3C XML Schema definitions into ASN.1" is an important building block for Fast Web Services because XSD is used in WSDL to define the structure of messages. Consequently, the XML schema referenced in a WSDL document can be considered an abstract schema, with an equivalent ASN.1 description, whose instances can be encoded using XML or an ASN.1 encoding. In the latter case it is possible to use an efficient binary encoding such as Packed Encoding Rules (PER).
ITU-T X.892 | ISO/IEC 24824-2 "Fast Web Services" consists of an ASN.1 Schema for SOAP as well as annotations for WSDL, but does not define any new specific binary encoding of XSD. There is no need to invent a new technology. Instead, the existing ASN.1 standards can be applied and if necessary evolved to meet future requirements. The standard can be
downloaded for free from the ITU-T website.
Fast Web Services annotations for WSDL allow services to explicitly state that a binding can support the
ITU-T X.892 | ISO/IEC 24824-2encoding (in addition to XML).
The ASN.1 schema for SOAP is based on the W3C SOAP 1.2 specification and ensures that the SOAP semantics and processing model are preserved. This enables WSDL-defined content to be efficiently encapsulated in a SOAP-based envelope using the same encoding technology. No changes to the SOAP binding syntax are required.
