Basic uncertainties about the nature of the comet-solar wind interaction have existed for decades, and even gross features of the interaction phenomena were poorly understood on theoretical grounds alone. The first discussions of measurements from the encounter of ICE (International Cometary Explorer) with Comet Giacobini-Zinner did not provide immediate clarification to these issues. Here we analyze the nature of the interaction by examining the detailed evolution of the plasma wave spectra across the interaction region. It is shown that the cometary spectra are very similar to those detected at certain classes of interplanetary shocks and terrestrial bow shocks.