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Team Comment on MTOM Serialization Policy Assertion (WS-MTOMPolicy) Submission

W3C is pleased to receive the MTOM Serialization Policy Assertion (WS-MTOMPolicy) from IBM and Microsoft.

WS-MTOMPolicy describes a domain-specific policy assertion that indicates endpoint support of the optimized MIME multipart/related serialization of SOAP messages defined in the MTOM specifications.


WS-MTOMPolicy defines a requirement for endpoints to generate messages serialized as specified in section 3 of the SOAP Message Transmission Optimization Mechanism W3C Recommendation, or the SOAP 1.1 Binding for MTOM 1.0 W3C Member Submission. The behavior applies to all messages in a binding. By marking the assertion as optional, it is possible to indicate support of non-MTOM-encoded exchanges for an endpoint.

The MTOM Serialization policy assertion establish two WSDL 1.1 policy attachment points for this policy assertion, wsdl:binding and wsdl:port, and excludes wsdl:portType as a possible attachment point. The behavior applies to all messages sent to or received from the Web service endpoint.

Section 3.2, Assertion Syntax, allows mandating the use of MTOM, which implies that a SOAP Node would refuse content sent with the SOAP media type (application/soap+xml). This would make the said Node non-compliant if the HTTP binding is used (Section 7.1.4, HTTP Media-Type, SOAP Version 1.2 Part 2: Adjuncts).

Next Steps

The W3C Team plans to notify the Web Services Coordination Group of this Member Submission. It is expected that this Submission will be used as input for the XML Protocol Working Group.

Yves Lafon, Web Services Activity Lead