If the SOAP message has an empty SOAP action, does not contain a SOAP action, or the SOAP action value cannot be resolved (i.e., no operation in the binder has the specified SOAP action value), Integration Server searches the binder for an operation with no defined SOAP action value or an empty SOAP action. If the binder contains a single operation that does not have a SOAP action value, Integration Server executes the IS service that corresponds to this operation. If the binder contains multiple operations without an assigned SOAP action value, Integration Server treats the absent SOAP action values as duplicate SOAP action values. For information about how Integration Server determines which operation to invoke when there are duplicate SOAP action values in a binder, see Duplicate SOAP Action.

If the binder does not contain an operation with an empty SOAP action, Integration Server compares the fully qualified name of the first element in the SOAP body to the expected first element for an operation. For operations with a Document style, the expected first element is the first part element declared for the operation’s input message in the WSDL document. For operations with an RPC style, the expected first element will have the same name as the operation in the WSDL document. Integration Server then invokes the IS service that corresponds to this operation.

If, after searching for the fully qualified name of the first element in the SOAP body, Integration Server cannot determine which operation to invoke, Integration Server returns a SOAP fault to the web service client.