Section: 6.5.3.4 UE requested bearer resource allocation procedure not accepted by the network 6.5.3.4.1 General
Content: If the bearer resource allocation requested cannot be accepted by the network, the MME shall send a BEARER RESOURCE ALLOCATION REJECT message to the UE. The message shall contain the PTI and an ESM cause value indicating the reason for rejecting the UE requested bearer resource allocation. The ESM cause value typically indicates one of the following: #26: insufficient resources; #30: request rejected by Serving GW or PDN GW; #31: request rejected, unspecified; #32: service option not supported; #33: requested service option not subscribed; #34: service option temporarily out of order; #35: PTI already in use; #37: EPS QoS not accepted; #41: semantic error in the TFT operation; #42: syntactical error in the TFT operation; #43: invalid EPS bearer identity; #44: semantic error(s) in packet filter(s); #45: syntactical error(s) in packet filter(s); #56: collision with network initiated request; #59: unsupported QCI value; #60: bearer handling not supported; #65: maximum number of EPS bearers reached; or #95 – 111: protocol errors. If the bearer resource allocation requested is for an established LIPA PDN connection or SIPTO at the local network PDN connection, then the network shall reply with a BEARER RESOURCE ALLOCATION REJECT message with ESM cause #60 "bearer handling not supported". If the requested new TFT is not available, then the BEARER RESOURCE ALLOCATION REJECT message shall be sent. The TFT in the request message is checked by the network for different types of TFT IE errors as follows: a) Semantic errors in TFT operations: 1) When the TFT operation is an operation other than "Create a new TFT". The network shall reject the allocation request with ESM cause #41 "semantic error in the TFT operation". b) Syntactical errors in TFT operations: 1) When the TFT operation = "Create a new TFT" and the packet filter list in the TFT IE is empty. 2) When there are other types of syntactical errors in the coding of the TFT IE, such as a mismatch between the number of packet filters subfield, and the number of packet filters in the packet filter list. The network shall reject the allocation request with ESM cause #42 "syntactical error in the TFT operation". c) Semantic errors in packet filters: 1) When a packet filter consists of conflicting packet filter components which would render the packet filter ineffective, i.e. no IP packet will ever fit this packet filter. How the network determines a semantic error in a packet filter is outside the scope of the present document. 2) When the resulting TFT does not contain any packet filter which applicable for the uplink direction. The network shall reject the allocation request with ESM cause #44 "semantic errors in packet filter(s)". d) Syntactical errors in packet filters: 1) When the TFT operation = "Create a new TFT" and two or more packet filters in the resultant TFT would have identical packet filter identifiers. 2) When the TFT operation = "Create a new TFT" and two or more packet filters among all TFTs associated with the PDN connection would have identical packet filter precedence values. 3) When there are other types of syntactical errors in the coding of packet filters, such as the use of a reserved value for a packet filter component identifier. In case 2, if the old packet filters do not belong to the default EPS bearer context, the network shall not diagnose an error, shall further process the new request and, if it was processed successfully, shall delete the old packet filters which have identical filter precedence values. Furthermore, the network shall perform an EPS bearer context deactivation request procedure to deactivate the dedicated EPS bearer context(s) for which it has deleted the packet filters. In case 2, if one or more old packet filters belong to the default EPS bearer context, the network shall release the relevant PDN connection using the EPS bearer context deactivation procedure. If it is the last remaining PDN connection and EMM-REGISTERED without PDN connection is not supported by the UE or the MME, the network shall detach the UE using detach type "re-attach required". Otherwise the network shall reject the allocation request with ESM cause #45 "syntactical errors in packet filter(s)". The network may include a Back-off timer value IE in the BEARER RESOURCE ALLOCATION REJECT message. If the Back-off timer value IE is included and the ESM cause value is different from #26 "insufficient resources" and #65 "maximum number of EPS bearers reached", the network may include the Re-attempt indicator IE to indicate: - whether the UE is allowed to attempt a secondary PDP context activation procedure in the PLMN for the same in A/Gb or Iu mode or a PDU session modification procedure in the PLMN for the same APN in N1 mode; and - whether another attempt in A/Gb and Iu mode, in S1 mode or in N1 mode is allowed in an equivalent PLMN. Upon receipt of a BEARER RESOURCE ALLOCATION REJECT message, the UE shall stop the timer T3480, release the traffic flow aggregate description associated to the PTI value, and enter the state PROCEDURE TRANSACTION INACTIVE.