15 manages the PDU session UP which is required when PDU sessions need to be transferred between Xn- and NG-related interfaces for handovers. 3GPP 38.410 defines NG (N2, N3 above) general aspects and principles for both CP and UP aspects. These include the Xn interface Layer 1 and signaling (CP) transport standards (3GPP 38.411 and 38.412) which define any SCTP/IP-based packet interface. 3GPP 38.413 defines the NG application protocol which is used to signal messages over the N2 interface. 3GPP 38.415 manages the PDU session UP which is required when PDU sessions need to be transferred between Xn- and NG-related interfaces for handovers. O-RAN specifications as written by O-RAN WG5 around these interfaces do not redefine any 3GPP interface specifications but define profiles (such as information elements to be supported) and expected message sequences that are expected to be supported by an O-RAN compliant vendor. Internet Protocol (IP) and Internet Protocol Security (IPSec) The Data Link Layer specifications for all transport networks such as NG and F1 interfaces define the use of any frame-based protocol, or in the bulk of the cases: IPv4 or IPv6. What is implicit in this definition is that when the backhaul is not physically secure, support for Internet Protocol Security (IPSec) becomes an implied requirement that can consume a large amount of compute/processing resources when requirements go to 10s or 100s of Gbps throughput associated with UP processing. Given the point-to-point nature of these links, the vast number of operators looks to deploy a single-tunnel mode implementation: it gives simplicity. However, other scenarios can ask for multiple tunnel support, including: traffic type separation including QoS-class-based differentiation or user plane/control plane separation; multiple 3GPP service deployments, such as mass-market and public safety concurrent deployment; Mobile Virtual Network Operator deployments that require separation on per-operator level, but also base station sharing scenarios (single 