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Reasons for RRC Connections Reestablishment

As per 3GPP spec, 36.331 (RRC Protocol Spec), RRC Connection Reestablishment initiates after these conditions occur :
1. Upon detection of RLF (Radio Link Failure)
2. After Handover failure
3. Integrity check failure indication received from lower layers.
4. RRC connection Reconfiguration Failure.
5. Mobility from E-UTRA failure.
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