LAU reject with cause Location Area Not Allowed
In this scenario is when network will send message to the mobile station(MS) mentioning LAU reject with cause as Location Area Not Allowed.
This cause is transmitted to mobile station(MS) when the MS is restricted region wise as shown in the figure. As shown in the figure, upper part of North America is rectricted for the MS and hence in that region MS will not get service with any of the PLMNs. Based on knowledge of subscribtion details of mobile station (MS), network will return this cause and reject the LAU request.
This cause is the one sent only by Home PLMN (HPLMN) to the MS. After receiving this cause MS enters into limited service mode. MS also will not search for any PLMNs.
As shown in the figure, let us assume that operator Verizon is providing service and as shown one subscriber is allowed to access the network service for this operator in the region marked with green and restricted in the above region. When mobile subscriber enters into the restricted region where in service is not available for it, network will send reject cause Location Area(LA) not allowed to the MS.