A SOAP message can carry binary data. The binary data is packaged with the SOAP message.
The packaged data is sent as a single stream over transport protocols, such as HTTP, SMTP, or the File Transfer Protocol (FTP).
The SOAP Messages with Attachments (SwA) specification is an abstract model that provides the basis for packaging attachments with a SOAP message.
The SwA specification is designed as a compound document structure that consists of a primary SOAP message part and zero or more secondary attachment parts.
The SwA specification is primarily implemented through Multipurpose Internet Mail Extension (MIME) and Direct Internet Message Encapsulation (DIME).