This subscriber data is used, among other things, for connection setup and service management. Depending on network size, number of subscribers and network organization, there may be several HLR registers in a GSM network. One HLR register can manage several 100,000 subscribers. The subscriber number indicates which GSM network the subscriber belongs to and in which Home Location Register his data is located. The location register is connected via Signalling System No 7 ( SS7).