Is both source and target are MFBI supporting cells?
There are two types of Handover defined X2 and S1.
When X2 handover disabled then MME handle handovers through S1 interface based on CPU load.
- If X2 is down.
- If there is no X2.
- If source and target eNB belongs to different MME pool.
- If source and target from different technology.
In this scenario S1 handover can trigger instead of X2 handover.