1. A method for managing performance of a multimedia content distribution network (MCDN), comprising: responsive to receiving an indication from a first MCDN client system of an impairment in MCDN performance, identifying a local MCDN node serving the first MCDN client system; identifying a community of MCDN client systems served by the local MCDN node, including the first MCDN client system; characterizing the MCDN client systems in the community based on an impairment parameter; identifying candidate MCDN client systems in the community based on said characterizing; and performing network diagnostics on the identified candidate MCDN client systems to predict a source of the impairment in MCDN performance.