 Not required RRC Signaling (AS) Required and terminated in eNB Required and terminated in eNB MAC Signaling (AS) Not required Not required RRC_CONNECTED mode between the UE and eNB, the UE is forced to idle mode. Table 8-1 shows the security termination points in 3GPP LTE. Integrity protection for the user-plane is not required, and thus is not supported between the UE and serving gateway or for the transport of user-plane data between the eNB and serving gateway on the S1 interface (i.e., the interface between eNB and MME). In general, on RRC_IDLE to RRC_CON- NECTED transition, RRC protection and user-plane protection keys are generated, while keys for NAS protection, as well as higher layer keys, are assumed to be already available in the MME. These higher layer keys may have been established in the MME as a result of an AKA run, or transferred from another MME during handover or idle mode mobility. On RRC_CONNECTED to RRC_IDLE tran- sition, eNB deletes the keys that it stores, SO that context for the idle mode UE only resides in the MME. The state and current keys of the UE are assumed to have been deleted at eNB on such tran- sition. In particular, the eNB and UE delete NH, KeNB, KRRCenc, KRRCint, KUpenc, and related Next Hop Chaining Counter (NCC), while MME and UE retain KASME, KNASint, and KNASenc- The RRC and user-plane keys are derived based on the algorithm identifiers and KeNB, which results in new RRC and user-plane keys in each handover. The source eNB and UE independently create KenB*. The KeNB* is provided to target the eNB during handover preparation time. Both the target eNB and UE consider the new KeNB equal to the received KeNB*. If AS keys (KUPenc, KRRCint, and KRRCenc) need to be changed in RRC_CONNECTED, an intra-cell handover is used. Inter-RAT handover from UTRAN to E-UTRAN is only supported after activation of integrity protection in UTRAN. References [1] IEEE Std 802.16-2009, IEEE Standard for Local and Metropolitan Area Networks - Part 16: Air Interface for Fixed Broadband Wireless Acc