Figure 1: (a) An illustration of a uniform wireless sensor network over a 2D domain. Destination nodes are located at the far edge. We show the possible path of a message originating from a node located in the left-front region. (b) An illustration of the collision protocol: reception at a node fails when one of its other neighbors transmits (regardless of the intended receiver). (c) An illustration of the time evolution of the queues in the 1D network model.