Service Orchestration with ESB Guidance 1.0

Hello guys, I have a good one for you interested on implementing ESB.

I’ve learned that ESB could helpme to build more complex services using the itineraries, but you also can create an orchestration (that will consume other services) to do some complex process and also expose this as a service.

For an architectural perspective I know that any application should access my services using the ESB, the cuestion here is, what happens with this orchestration i want to create to be a service? How do the orchestration needs to access to the services?? Do I need to contact the itinerary  services installed with ESB (like if the orchestration is an application)? Or should the orchestration go directly to the services??

What do you think?