Mobile Terminated Call • The calling party dials the MSISDN for the mobile subscriber. • The PSTN identifies the network (PLMN) that the dialed MSISDN belongs to and will locate a GMSC for that network. • The PSTN sends an Initial Address message to the GMSC. •T he GMSC forwards the MSISDN to the HLR and requests routing information for it. • The HLR looks up the MSISDN and determines the IMSI and the SS7 address for the MSC/VLR that is servicing the MS. •T he HLR then contacts the servicing MSC/VLR and asks it to assign a Mobile Station Routing Number (MSRN) to the call. (a MSRN is assigned to the call not to the MS itself. ) • The MSC/VLR allocates the MSRN and forwards it to the HLR.