Message Exchange Pattern

A Message Exchange Pattern (MEP) describes the pattern of messages [ [http://www.serviceoriented.org/message_exchange_pattern.html Message Exchange Pattern ] ] required by a communications protocol to establish or use a communication channel. There are two major message exchange patterns — a "request-response" pattern, and a "one-way" pattern. For example, the TCP has a "request-response" pattern protocol, and the UDP has a "one-way" pattern.

The term has a similar and specific meaning within the SOAP protocol. [http://www.w3.org/TR/soap12-part1/#soapmep SOAP MEPs in SOAP W3C Recommendation v1.2] [ [http://www.w3.org/TR/wsdl20-additional-meps/ Web Services Description Language (WSDL) Version 2.0: Additional MEPs ] ] SOAP MEP types include:
# In-Only: This is equivalent to "one-way". A standard one-way messaging exchange where the consumer sends a message to the provider that provides only a status response.
# Robust In-Only: This pattern is for reliable one-way message exchanges. The consumer initiates with a message to which the provider responds with status. If the response is a status, the exchange is complete, but if the response is a fault, the consumer must respond with a status.
# In-Out: This is equivalent to "request-response". A standard two-way message exchange where the consumer initiates with a message, the provider responds with a message or fault and the consumer responds with a status.
# In Optional-Out: A standard two-way message exchange where the provider's response is optional.
# Out-Only
# Robust Out-Only
# Out-In
# Out-Optional-In

See also

* REST
* JBI

References