This image shows a box at the top labeled BPEL Process. Incoming and outgoing arrows connect the bottom of this box with a box immediately below labeled WSIF Invocation Layer. An incoming arrow connects the bottom of the box labeled WSIF Invocation Layer with a box immediately below labeled OutputHeaderHandler. An outgoing arrow connects the bottom of the box labeled WSIF Invocation Layer with a box immediately below labeled InputHeaderHandler. An outgoing arrow connects the bottom of the box labeled InputHeaderHandler with a box immediately below labeled WSIF Provider. An incoming arrow connects the bottom of the box labeled OutputHeaderHandler with the box immediately below labeled WSIF Provider.