The Xw user plane interface (Xw-U) is defined between eNB and WT. The Xw-U interface provides non guaranteed
delivery of user plane PDUs. The transport network layer is built on IP transport and GTP-U is used on top of UDP/IP to carry the user plane PDUs.
The Xw control plane interface (Xw-C) is defined between an eNB and a WT. The transport network layer is built on SCTP on top of IP. The application layer signalling protocol is referred to as Xw-AP (Xw Application Protocol).