Which of the following about CMG CUPS architecture is FALSE?

The statement that the CMG control plane (CMG-C) VNF can be deployed in LB-less mode is false. The LB-less deployment architecture is a specific performance and scalability optimization designed for the high-throughput user plane (CMG-U) VNF. This mode allows the CMG-U to bypass a centralized load balancer for the data path, reducing latency and bottlenecks. The CMG-C, which handles signaling traffic, is deployed in standard high-availability configurations (e.g., active/standby pairs) that are typically fronted by a load balancer for distributing signaling messages, but it does not utilize the "LB-less" architecture specific to the user plane.

A. The core principle of CUPS is the separation of functions. The CMG user plane (CMG-U) VNF is explicitly designed to implement the data forwarding components: Serving Gateway User Plane (SGW-U), Packet Data Network Gateway User Plane (PGW-U), and GPRS Gateway Support Node User Plane (GGSN-U).
B. The Sx interface is the 3GPP-defined reference point connecting the control plane and user plane elements in a CUPS architecture. The Nokia 7750 SR Mobile Gateway (MG) implements the CMG-U function and uses the Sx interface to communicate with the CMG-C VNF.
D. The CMG user plane (CMG-U) VNF supports multiple deployment models to meet diverse performance and scalability requirements. This includes a traditional load-balanced (LB) mode and a high-performance LB-less mode, which is often preferred for demanding user plane workloads.

1. Nokia Cloud Mobile Gateway (CMG) Solution Description, Release 21, Document ID: D578000194.

Section 3.1, "CMG CUPS Architecture": This section details the functional split, confirming that the CMG-U VNF embodies the SGW-U, PGW-U, and GGSN-U functionalities (validating option A). It also describes the Sx interface as the communication path between the CMG-C and CMG-U (validating option B).

Section 4.2, "CMG User Plane Deployment Models": This section explicitly describes the LB-mode and LB-less mode as deployment options for the CMG-U VNF (validating option D). The document does not describe an "LB-less" mode for the CMG-C, instead detailing its deployment in active/standby pairs for resiliency (invalidating option C).

2. 3GPP TS 23.214, "Architecture enhancements for control and user plane separation of EPC nodes; Stage 2".

Section 5.2, "Reference points": This specification officially defines the Sx reference point and its variants (Sxa, Sxb, Sxc) as the interface between the separated control plane and user plane functions of the SGW, PGW, and TDF. This provides the standards-based validation for option B.