A method of preventing collisions when a cable modem re-registers with a cable modem termination system on a cable television network following failure of a primary communications channel between the cable modem and the cable modem termination system. The method provides a service identifier that is transmitted to the cable modem during initial registration of the cable modem with the cable modem termination system. Upon registration of the cable modem with the cable modem termination system, the cable modem stores the service identifier in memory. After failure of the primary channel, the cable modem reinitializes on the cable network and waits for transmission of a bandwidth allocation map from the cable modem termination system. When the cable modem receives the bandwidth allocation map, it determines if the map contains a unicast initial maintenance opportunity. When the map contains a initial maintenance opportunity having a unicast associated identifier, the cable modem compares the service identifier stored in its memory with a unique service identifier contained in the initial maintenance opportunity information element of the bandwidth allocation map. When the service identifiers match, the cable modem then uses the initial maintenance opportunity having the unicast associated identifier contained in the information element of the bandwidth allocation map to re-register with the network.