The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 .

With the exception of examples and sections explicitly marked as "Non-Normative", all parts of this specification are normative.

This message exchange pattern is identified by the URI (see SOAP 1.2 Part 1 SOAP Features):

The SOAP One-way MEP defines properties for the exchange of a SOAP message. In the absence of failure in the underlying protocol, this MEP consists of one SOAP message. The scope of a one-way MEP is limited to the exchange of a message between one sending and one receiving SOAP node. Implementations MAY choose to support multiple meps at the same time.

The sending node MUST send the SOAP Message provided in http://www.w3.org/2003/05/soap/mep/OutboundMessage to the node identified by http://www.w3.org/2003/05/soap/mep/ImmediateDestination. The sender is not required to detect whether transmission succeeds or fails, but the sender SHOULD fault in a binding specific manner if it discovers that transmission is unsuccessful.

The receiving node MUST determine whether a given message is successfully received, and if so, MUST populate http://www.w3.org/2003/05/soap/mep/InboundMessage with the received message AND MUST process the message in http://www.w3.org/2003/05/soap/mep/InboundMessage according to the SOAP Processing Model (see SOAP 1.2 Part 1 Processing SOAP messages). Determination of success by the receiver MAY be conservative, I.e. the receiver may in exceptional circumstances treat as erroneous or lost a message which is received intact (typical reasons for making such decisions might include shortage of buffer space, network interface overruns, etc.). Receivers MAY fault in a binding-specific manner if some particular message is declared in error (note, however, that in many cases where receipt is unsuccessful, information identifying the message or its sender may be unreliable, in which case there may be little if any value in reflecting a message-specific fault.)

Abnormal operation during a one-way message exchange might be caused by a failure to transfer the message or a failure at the receiving SOAP node to process the message. Such failures might be silent at either or both of the sending and recieving SOAP nodes involved, or might result in the generation of a SOAP or binding-specific fault (see ). Also, during abnormal operation each SOAP node involved in the message exchange might differ in its determination of the successful completion of the message exchange.

The One-way MEP defines a set of properties described below.

There may be other properties related to the operation of the message exchange and are processed according to their own feature specifications.

During the operation of the One-way MEP, the participating SOAP nodes may generate SOAP faults. This MEP makes no claims about the disposition or handling of SOAP faults generated by the sending SOAP node or the receiving SOAP node.