Another common situation is that users find using XA too slow to bridge each message from one provider to another, so instead opt for "DUPS_OK" quality of service mode, and then just detect duplicates in their own code at the end. This can often be much faster than using XA and gives the same overall reliability guarantee, but in order to do that you need to know that the bridge always sends the message on before acking it to the source (i.e. dups_ok) so in case of failure you know you will never lose any messages but may get duplicates. So fine grained qos control is useful there. Then you might have other uses who never want duplicate messages, but don't mind losing a few - this is "at most once" delivery in messaging terminology. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4139386#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...