onally installs) a complete "kit" of equipment to deploy a site-as well as to guarantee successful operation. The equipment itself can either be highly custom and optimized or made from a combination of commercial software stacks running on relatively general- purpose hardware. The latter "white box" systems are becoming more and more popular due to ease of development and support of a wide range of deployment options. When considering system integrator choice, consider what the target features of the system will be: network services; mobility/handover support; interoperability with commercial operator networks; QoS requirements such as voice, video, and industrial/URLLC; and integration with other applications, such as (Metro) Edge Computing, virtualized services, and application integration. Client equipment modem cards/clients with proven interoperability with the deployed network; general-purpose (EQ mobile phones) or application-specific (URLLC/industrial Ethernet bridges); and SIM cards. Indoor versus outdoor deployment which impacts both RF aspects (output power/EIRP) as well as form factor (passive or active cooling, hardware noise, moisture, and dust resilience) and other related topics. This sets the boundaries around the system that can be deployed. Regulatory requirements-location, transmit power, sensing, and registration are unique per geography as we discussed. What are the RF testing requirements that need to be finished and how do they impact design and hardware timeline? And obviously, the RF specifications define the target system requirements. Security requirements that are often overlooked. Does the system have a secure-boot requirement, or can it be assumed in a safe-enough environment protected by other factors? What is the process for applying critical software patches without disrupting user experience? 36 Open Radio Access Network (O-RAN) Systems Architecture and Design System optimization point. It is impossible to design a system that both scales to every possible performance point whi