Section: 4.7.3.1.6 Abnormal cases on the network side
Content: The following abnormal cases can be identified: a) Lower layer failure If a low layer failure occurs before the message ATTACH COMPLETE has been received from the MS and a new P-TMSI (or a new P-TMSI and a new P-TMSI signature) has been assigned, the network shall consider both the old and new P-TMSI each with its corresponding P-TMSI-signature as valid until the old P-TMSI can be considered as invalid by the network (see subclause 4.7.1.5) or the GMM context which has been marked as detached in the network is released, and shall not resent the message ATTACH ACCEPT. 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. b) Protocol error If the ATTACH REQUEST message is received with a protocol error, the network shall return an ATTACH 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 ATTACH ACCEPT message and shall reset and restart timer T3350. This retransmission is repeated four times, i.e. on the fifth expiry of timer T3350, the GPRS attach procedure shall be aborted. If a new P-TMSI or a new P-TMSI together with a new P-TMSI signature were allocated in the ATTACH ACCEPT message, the network shall consider both the old and new P-TMSI each together with 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) or the GMM context which has been marked as detached in the network is released. During this period the network acts as specified for case a. d.1) ATTACH REQUEST received after the ATTACH ACCEPT message has been sent and before the ATTACH COMPLETE message is received - If one or more of the information elements in the ATTACH REQUEST message differ from the ones received within the previous ATTACH REQUEST message, the previously initiated GPRS attach procedure shall be aborted if the ATTACH COMPLETE message has not been received and the new GPRS attach procedure shall be progressed, or - If the information elements do not differ, then the ATTACH ACCEPT message shall be resent and the timer T3350 shall be restarted if an ATTACH COMPLETE message is expected. In that case, the retransmission counter related to T3350 is not incremented. d.2) More than one ATTACH REQUEST received and no ATTACH ACCEPT or ATTACH REJECT message has been sent - If one or more of the information elements in the ATTACH REQUEST message differs from the ones received within the previous ATTACH REQUEST message, the previously initiated GPRS attach procedure shall be aborted and the new GPRS attach procedure shall be progressed; - If the information elements do not differ, then the network shall continue with the previous attach procedure and shall not treat any further this ATTACH REQUEST message. e) ATTACH REQUEST received in state GMM-REGISTERED If an ATTACH REQUEST message is received in state GMM-REGISTERED the network may initiate the GMM common procedures; if it turned out that the ATTACH REQUEST message was send by an MS that has already been attached, the GMM context, PDP contexts and MBMS contexts, if any, are deleted and the new ATTACH REQUEST is progressed. f) ROUTING AREA UPDATE REQUEST message received before ATTACH COMPLETE message. Timer T3350 shall be stopped. The allocated P-TMSI shall be considered as valid and the routing area updating procedure shall be progressed as described in subclause 4.7.5. g) DETACH REQUEST message received before ATTACH COMPLETE message. The network shall abort the attach procedure and shall progress the detach procedure as described in subclause 4.7.4.1. Figure 4.7.3/1 3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] : GPRS attach procedure and combined GPRS attach procedure