This standard describes the concept of Event Messages used to collect usage for the purposes of billing within the IPCablecom architecture. It details a transport protocol independent Event Message attribute TLV format, an Event Message file format, mandatory and optional transport protocols, the various Event Messages, lists the attributes each Event Message contains, and lists the required and optional Event Messages associated with each type of enduser service supported. In order to support vendor interoperability, implementations must minimally support RADIUS as a transport protocol.