UE communicates with MME by the NAS layer messages which are transparently transferred by the eNodeB.
Does eNB communicates with another eNB using wireless medium or using wired medium ?
UE send selected PLMN information to eNodeB by using the RRC connection setup complete message. How MME comes to know about selected PLMN since I did not find selected PLMN ID inS1-AP "Intial Ue Message" ?