CSFB: How signalling messages are exchanged in CSFB when UE moves from LTE to Legacy network ?

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Assuming one case when UE was in LTE network and data transmission was ongoing. Due to incoming voice call, UE leaves LTE network and moves to legacy network to finish voice call. I want to know what will happen with ongoing data session in LTE network.
Does the LTE network deletes UE context ? Does the LTE network buffers UE data coming in downlink direction ? Or UE establishes voice as well as data session is legacy network and he continues voice and data services (less through due to legacy network speed) in case UE and legacy network both support DTM (Dual transmission mode) ?

posted Jul 26, 2017 by Harshita

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