Cellular network connectivity procedures

A computer implemented method for managing requests to register subscription devices for service with one or more cellular networks is provided. The method involves storing data representing a plurality of registration records, each being indicative of a respective subscription device being registered for service with a respective cellular network using a respective IMSI. A request to register a subscription device for service is received, the request including at least an IMSI and being associated with one or more request characteristics. An outcome for the request is generated based on whether the plurality of registration records are indicative of another subscription device being registered for service, and if so, at least one of the one or more request characteristics. A computer system for performing the method, and a non-transitory computer readable storage medium are also provided.