Xn interface in the 5G RAN is as same as X2 interface of LTE RAN. It enables communication between the following nodes:
- ng-eNB and ng-eNB
- ng-eNB and gNB
- gNB and gNB
It is divided into control and user plane. Control plane of this interface uses SCTP as transport and it is mainly used for UE mobility, context transfer, RAN paging, Dual connectivity and interface management. The user plane part of Xn interface provides data forwarding and flow control. The user plane is based on GTP-U protocol stack.