Section: 4.7.5.1.6 Abnormal cases on the network side
Content: The following abnormal cases can be identified: a) If a lower layer failure occurs before the message ROUTING AREA UPDATE COMPLETE has been received from the MS and a P-TMSI and/or PTMSI signature has been assigned, the network shall abort the procedure and shall consider both, the old and new P-TMSI and the corresponding P-TMSI signatures as valid until the old P-TMSI can be considered as invalid by the network (see subclause 4.7.1.5). During this period the network may use the identification procedure followed by a P-TMSI reallocation procedure if the old P-TMSI is used by the MS in a subsequent message. NOTE 1: Optionally, paging with IMSI may be used if paging with old and new P-TMSI fails. Paging with IMSI causes the MS to re-attach as described in subclause 4.7.9.1. b) Protocol error If the ROUTING AREA UPDATE REQUEST message has been received with a protocol error, the network shall return a ROUTING AREA UPDATE REJECT message with one of the following reject causes: #96: Mandatory information element error; #99: Information element non-existent or not implemented; #100: Conditional IE error; #111: Protocol error, unspecified. c) T3350 time-out On the first expiry of the timer, the network shall retransmit the ROUTING AREA UPDATE ACCEPT message and shall reset and restart timer T3350. The retransmission is performed four times, i.e. on the fifth expiry of timer T3350, the routing area updating procedure is aborted. Both, the old and the new P-TMSI and the corresponding P-TMSI signatures shall be considered as valid until the old P-TMSI can be considered as invalid by the network(see subclause 4.7.1.5). During this period the network acts as described for case a above. Figure 4.7.5/1 3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] : Routing and combined routing area updating procedure d.1) ROUTING AREA UPDATE REQUEST received after the ROUTING AREA UPDATE ACCEPT message has been sent and before the ROUTING AREA UPDATE COMPLETE message is received - If one or more of the information elements in the ROUTING AREA UPDATE REQUEST message differ from the ones received within the previous ROUTING AREA UPDATE REQUEST message, the previously initiated routing area updating procedure shall be aborted if the ROUTING AREA UPDATE COMPLETE message has not been received and the new routing area updating procedure shall be progressed, or - If the information elements do not differ, then the ROUTING AREA UPDATE ACCEPT message shall be resent and the timer T3350 shall be restarted if an ROUTING AREA UPDATE COMPLETE message is expected. In that case, the retransmission counter related to T3350 is not incremented. d.2) More than one ROUTING AREA UPDATE REQUEST received and no ROUTING AREA UPDATE ACCEPT or ROUTING AREA UPDATE REJECT message has been sent - If one or more of the information elements in the ROUTING AREA UPDATE REQUEST message differs from the ones received within the previous ROUTING AREA UPDATE REQUEST message, the previously initiated routing area updating procedure shall be aborted and the new routing area updating procedure shall be progressed; - If the information elements do not differ, then the network shall continue with the previous routing area updating procedure and shall not treat any further this ROUTING AREA UPDATE REQUEST message. e) DETACH REQUEST message received before the ROUTING AREA UPDATE ACCEPT message is sent or before the ROUTING AREA UPDATE COMPLETE message (in case of P-TMSI and/or TMSI was allocated) is received. GPRS detach containing cause "power off": The network shall abort the signalling for the routing area updating procedure towards the MS and shall progress the detach procedure as described in subclause 4.7.4.1. NOTE 2: Internally in the network, before processing the detach request, the SGSN can perform the necessary signalling procedures for the routing area updating procedure before progressing the detach procedure. GPRS detach containing other causes than "power off": The network shall proceed with the routing area updating procedure and shall progress the detach procedure after successful completion of the routing area updating procedure. f) ROUTING AREA UPDATE REQUEST message with update type IE indicating "periodic updating" is received by the network, the network does not have the GMM context data related to the subscription, and the network operates in network operation mode I. The network may send the ROUTING AREA UPDATE REJECT message with GMM cause value #10 "Implicitly detached".