
Chapter 7. Web services roadmap 125
Figure 7-3 WS-I basic interaction models
WS-I have not yet dealt with more complex styles of interaction familiar to
MOM architects such as in Figure 7-4.
Figure 7-4 Examples of more complex point-to-point interaction styles
3. Callback (A message is solicited by the invoker, either as a separate callback)
4. Multi-hop (such as through a gateway or an ESB)
In the multi-hop example in Figure 7-4, the requests to a single provider are
routed through different gateways (by an load balancing scheme perhaps). In
this example, the gateway needs to be able to insert return routing