A user device connected to a CMTS over a network is configured such that upon power-up it can use a universal broadcast SID or a predetermined multicast SID to obtain an initial maintenance during a maintenance window. The predetermined multicast SID is assigned to the device at manufacture based on the type, or class, of device. The CMTS to which the devices connect is configured to schedule exclusive initial maintenance opportunity windows for each type of device in addition to an all-inclusive, or open, initial maintenance opportunity window, during which all types of devices may attempt to register. The order and number of initial maintenance windows within a periodically recurring sequence of windows can be configured by an operator based on the types of devices connected to the network.