What is SOAP MTOM?

SOAP Message Transmission Optimization Mechanism (MTOM) is the use of MIME to optimize the bitstream transmission of SOAP messages that contain significantly large base64Binary elements.

The MTOM message format allows bitstream compression of binary data. Data that would otherwise have to be encoded in the SOAP message is instead transmitted as raw binary data in a separate MIME part. A large chunk of binary data takes up less space than its encoded representation, so MTOM can reduce transmission time, although it can increase processor usage. Candidate elements to be transmitted in this way are defined as base64Binary in the WSDL (XML Schema).

An MTOM message is identified by a Content-Type with a type of application/xop+xml.

The SOAP domain handles inbound MTOM messages automatically, and MTOM parts are reincorporated automatically into the SOAP Body.

The use of outbound MTOM messages can be configured on the SOAPReply, SOAPRequest, and SOAPAsyncRequest nodes; for details, see SOAP MTOM and the SOAPReply, SOAPRequest, and SOAPAsyncRequest nodes.

For details of the external specification published by the World Wide Web Consortium (W3C), see SOAP MTOM.