Due to SON, each eNodeB awares about the cells supported by its neighbor eNodeB. If due to Network Management system or administrative reason, any of cells supported by an eNodeB goes down, eNodeB sends "ENODEB CONFIGURATION UDPATE" message to inform to its neighbor eNodeBs and receives acknowledgement from neighbors through "ENODEB CONFIGURATION UPDATE ACKNOWLEDGE" message.
If an eNodeB wants to get activate one or more cells of its neighbor eNodeB, it sends "CELL ACTIVATE REQUEST" message along with intended list of cells to its neighbor enodeB. If receiving eNodeB is not able to switch on or activate a single cell present is the list, eNodeB responds with "CELL ACTIVATE FAILURE" message.
If at least one of the cell present is the list gets activated, eNodeB responds with "CELL ACTIVATE RESPONSE" message.