Which of the following boards is added, the base station Is reset and you need to log in to the LMT again?

Adding a Universal Baseband Processing Unit (UBBP) board increases the base station's cell processing capacity. This is a significant change to the system's hardware resources. The main control board (UMPT) must re-initialize the system to recognize and integrate the new board into the resource pool. This re-initialization process involves a reset of the entire base station. Consequently, any active LMT (Local Maintenance Terminal) session will be disconnected, requiring the user to log in again after the reset is complete.

A. A UMPT is the main control board; adding a second one for redundancy is a major operation, but adding a UBBP is a more common expansion that necessitates a reset.
C. The UPEU (power unit) is designed to be hot-swappable. Adding or replacing it does not require a system reset, ensuring service continuity.
D. The UEIU (environment interface unit) is also hot-swappable. Its addition or replacement does not impact the base station's core functions or require a reset.

Huawei Technologies Co., Ltd. (2020). 3900 & 5900 Series Base Station Maintenance Guide. Document Version 25. Chapter "Board Replacement", Section "Replacing a UBBP". This guide specifies that adding or replacing baseband processing units requires a base station reset.

Huawei Technologies Co., Ltd. (2020). SingleRAN LTE FDD MML Command Reference. Document Version SRAN16.1. The command ADD BRD (Add Board) documentation notes that adding certain board types, like a UBBP, will trigger a board or system reset.