Instead of chosing a static route ahead of time, ExOR defers the choice of the next forwarding node until the reception of the packet which is to be routed. The forwarding is done by the node closest to the destination, so the route is built dynamically. Using a mechanism of acknowledgements (ACKs), we can ensure, that only one node forwards the packet.
Let's look at an example transmission, taking place in the network represented by the following figure, where the edges are labeled with the delivery ratios (= probability of reception):