There are three types of interaction:

Basic interactions like panning the view are processed locally on the client side. They are fast and no requests are sent to the servlets.

When using advanced interactors like the select interactor (selectInteractor), you can choose the invocation context, or how the submitted request will be processed. There are two options:

When the JSF lifecycle processes a request, it follows well-defined phases, respecting listeners, triggering actions and notifying components. The response forces all the pages to be updated at the end, and the network or equipment component executes the DHTML code to request a new image from the image servlet. At least two roundtrips to the server take place.

When the request goes straight to the image servlet (IMAGE_SERVLET_CONTEXT), the processing is faster, as only the networkView or equipmentView component is updated. The response carries the new image in one single roundtrip to the server. The drawbacks are that no other faces component is updated, and that the results may be inconsistent.