Section: 5.5.1.2.3 S1-based handover, Reject
Content: The Target eNodeB rejects the use of the Handover procedure if none of the requested bearers in the Handover Request message could be established. In this case no UE context is established in the target MME/eNodeB and no resources are allocated. Further, the Target MME rejects the handover request and clears all resource in Target eNodeB and Target MME if the Target eNodeB accepts the handover request but none of the default EPS bearers gets resources allocated. In both cases, the UE remains in the Source eNodeB/MME. Figure 5.5.1.2.3-1: S1-based handover, Reject NOTE 1: Steps 3, 4, 7 and 8 are performed if the MME is relocated. NOTE 2: If the MME is not relocated Steps 5 and 6 are performed by the source MME and, in the description below, the source MME acts as the target MME. 1-5. Steps 1 to 5 in the flow are identical to steps 1-5 in clause 5.5.1.2.2. 6a. If the Target eNodeB fails to allocate any resources for any of the requested EPS bearers it sends a Handover Failure (Cause) message to the Target MME. The Target MME clears any reserved resources for this UE in the target MME. 6b. If the Target MME receives a Handover Request Acknowledge message from the Target eNodeB but none of the default EPS bearers are in the EPS Bearer Setup list IE, the Target MME clears any reserved resources for this UE in both the Target MME and the Target eNodeB. 7. This step is only performed for Serving GW relocation, i.e. if steps 4/4a have been performed. The Target MME deletes the EPS bearer resources by sending Delete Session Request (Cause) messages to the Target Serving GW. The Target Serving GW acknowledges with Delete Session Response (Cause) messages. 8. The Target MME sends the Forward Relocation Response (Cause) message to the Source MME. 9. When the Source MME receives the Forward Relocation Response message, it sends a Handover Preparation Failure (Cause) message to the Source eNodeB.