A Routing action can only be used inside a Route node and will always have to be placed at the end of the proxy service message flow. No other actions can follow a routing node in the message flow. The Routing action will define where the request thread stops and where the response thread starts. The request and response pipeline of an OSB proxy service are always executed in two different threads. A Routing action supports both request/response as well as one-way message exchange patterns.
The Service Callout action can be placed anywhere where an OSB action is valid. There is no limit for the number of Service Callout actions which can be used. A Service Callout placed in the request pipeline will be performed by the request thread, a Service Callout in the response pipeline by the response thread. A Service Callout only supports the request/ response message exchange pattern and will always be synchronous, that is, it waits for the response message.
