A method implemented in a computer system for determining upstream transmission capability in an area of a hybrid fiber-coaxial (HFC) cable plant network, the area including network components, and customer premises equipment (CPE) devices. The method configures a downstream transmission that includes a marker channel, and initiates the downstream transmission to each CPE device. The method sends a query to each CPE device to request a status of the marker channel at the CPE device. The method receives a response to the query from at least one CPE device, and determines a status of each network component based on the response to the query from said at least one CPE device subtending from the network component.