Addition of AgI causes remarkable increases in the Ag+-ion conductivity of glass, and in some cases to the appearance of prepeaks in neutron scattering data (at Q = ca. 0.8 Angstrom(-1)). The origins of these prepeaks are discussed in relation to possible structural models. It is suggested that the enhanced conductivity is related to the formation of AgI clusters, but that local structure in the glass especially at the edge of these clusters is continuously modified by the mobile Ag+ ions. According to the dynamic structure model, the mechanism of cation transport in AgI-based glasses therefore resembles that in other cation-conducting glasses.