Section: 11.1 Multiple TNLAs for Xn-C
Content: In the following, the procedure for managing multiple TNLAs for Xn-C is described. Figure 11.1-1: Managing multiple TNLAs for Xn-C. 1. The NG-RAN node1 establishes the first TNLA with the NG-RAN node2 using a configured TNL address. NOTE: The NG-RAN node1 may use different source and/or destination IP end point(s) if the TNL establishment towards one IP end point fails. How the NG-RAN node1 gets the remote IP end point(s) and its own IP address are outside the scope of this specification. 2-3. Once the TNLA has been established, the NG-RAN node1 initiates the Xn Setup procedure to exchange application level configuration data 4-6. The NG-RAN node2 may add additional TNL Endpoint(s) to be used for Xn-C signalling between the NG-RAN node1 and the NG-RAN node2 pair using the NG-RAN node Configuration Update procedure. NG-RAN node Configuration Update procedure also allows the NG-RAN node2 to request the NG-RAN node1 to modify or release TNLA(s). 7-9. The NG-RAN node1 may add additional TNL Endpoint(s) to be used for Xn-C signalling between the NG-RAN node1 and the NG-RAN node2 pair using the NG-RAN node Configuration Update procedure. NG-RAN node Configuration Update procedure also allows the NG-RAN node1 to request the NG-RAN node2 to modify or release TNLA(s). The XnAP UE TNLA binding is a binding between a XnAP UE association and a specific TNL association for a given UE. After the XnAP UE TNLA binding is created, the NG-RAN node1 or the NG-RAN node2 can update the UE TNLA binding by sending the first available XnAP message for the UE to the peer NG-RAN node via a different TNLA. The peer NG-RAN node shall update the XnAP UE TNLA binding with the new TNLA.