er of other protocol networks can be identified as well: The roaming network, ROA, uses the information provided by BRO to find suitable radio channel to connect to. When connected, the MS can make service accesses (over SH) and receive pages (over PAG.) ROA consists of a single ele- ment in MSs. The handover network, HO, operates on established calls. HO is a protocol net- work that analyses to which cell to do a handover, and controls the handover procedure. The HO network uses the services of the LOC network and of the connection handling network (COH). HO provides its service to the service han- dling network (SH). The HO network is represented by protocol elements in MS, BSC and MSC. The locating protocol network, LOC, also operates on established calls. It uses the information provided by BRO to identify nearby cells that may be suitable for handover, once the signal strength in the actual cell gets too low. The LOC network only decides when a handover is needed, but leaves HO to implement the handover. LOC in MS makes continuous signal strength measurements. The MS sends measurement data continuously to LOC in the BSC, where the analy- sis is done. Thus, LOC has protocol elements in MS and in BSC. LOC provides a service to HO and depends on the services provided by BRO. The equipment identity control protocol network, EIC, is a support network to the SH, in the same way as AC and REG. The EIC network is represented by protocol elements in MSC, EIR and OSS. The paging protocol network, PAG, pages MSs. It could be defined as part of the SH, but since paging has become a separate service that the circuit-switched GSM can order from the GPRS part, it should be isolated from SH. PAG has protocol elements in MSC, BSC and MS. The connection handling network, COH, sets up circuit-switched connections over the whole GSM network. It provides its services to the service handling network (SH) and to the handover network (HO). COH has protocol elements in MS, BSC, MSC and GMCS. The separation of the COH from the SH is 