ORAN Interview Questions
- What is the full form of O-RAN and what is its main objective?
- Briefly describe the journey from traditional RAN to O-RAN.
- What motivated the creation of the O-RAN Alliance?
- Name at least three founding members of the O-RAN Alliance.
- Explain how O-RAN promotes multi-vendor interoperability.
- What are the three main pillars of O-RAN?
- Define the term “open interfaces” in the O-RAN context.
- What is the difference between open RAN and virtualized RAN (vRAN)?
- Explain the importance of “disaggregation” in O-RAN.
- How does O-RAN impact vendor lock-in for operators?
- What is the difference between proprietary RAN and O-RAN?
- Describe the O-RAN approach to RAN intelligence and automation.
- How does O-RAN support innovation and ecosystem growth?
- List two major global operator groups actively driving O-RAN adoption.
- What role does open source software play in the O-RAN ecosystem?
- How does O-RAN drive down the cost of 5G deployments?
- What is “white-box” hardware and why is it important for O-RAN?
- How does O-RAN facilitate the deployment of small cells?
- Explain the term “RAN sharing” and how O-RAN enhances it.
- What is the relationship between 3GPP and O-RAN specifications?
- What are the main building blocks of O-RAN architecture?
- What is the primary function of the O-RU (Radio Unit)?
- What is the O-DU (Distributed Unit) responsible for?
- What are the O-CU (Centralized Unit) main roles?
- What is the SMO (Service Management and Orchestration) in O-RAN?
- Describe the role of the RAN Intelligent Controller (RIC).
- Differentiate between Near-RT RIC and Non-RT RIC.
- What are xApps and where do they run?
- What are rApps and what is their purpose?
- Which O-RAN node interfaces directly with user equipment (UE)?
- Which O-RAN node is responsible for MAC/PHY layer functions?
- Which node typically handles RRC and SDAP processing?
- What is the role of the Network Management System (NMS) in O-RAN?
- Explain the hierarchy between SMO, RIC, and DU/CU.
- What is the function of the Management Plane (M-Plane)?
- What is the CUS-Plane and what are its sub-planes?
- Explain the purpose of the O1 interface.
- What is the O2 interface and its role?
- What is the E2 interface used for?
- What is the A1 interface and between which nodes does it run?
- What are the standard interfaces between O-RU, O-DU, and O-CU?
- Explain the function and structure of the open fronthaul interface.
- What protocol is commonly used over the open fronthaul (O-DU to O-RU)?
- What is eCPRI and why is it preferred over CPRI in O-RAN?
- What are the Control, User, and Synchronization Planes (CUS) in O-RAN?
- Explain the responsibilities of the M-Plane in O-RAN.
- What protocols are used for M-Plane management?
- Describe the use of NETCONF/YANG in O-RAN.
- What is SSH used for in O-RAN M-Plane communications?
- What is the function of the O-RU “Call Home” feature?
- What is a functional split in O-RAN?
- List all 3GPP-defined functional split options and their split points.
- What is the most widely adopted split option in O-RAN and why?
- Describe Option 7-2x split and its main advantages.
- Compare high-layer and low-layer functional splits.
- What are the main data flows in Option 7-2x split?
- What are the trade-offs between Option 2 and Option 7-2x splits?
- How does functional split impact fronthaul bandwidth requirements?
- What data flows are exchanged on the User Plane (U-Plane)?
- How are IQ samples transmitted in the O-RAN fronthaul?
- What is the Control Plane (C-Plane) responsible for in O-RAN?
- What are the main functions of the User Plane (U-Plane)?
- Describe the Synchronization Plane (S-Plane) and its importance.
- What is the role of an IEEE 1588 Grand Master in O-RAN?
- What is the purpose of the S-Plane protocol stack?
- What timing parameters must be managed for C-Plane and U-Plane coordination?
- What is Tcp_adv_dl and why is it important?
- Explain how C-Plane and U-Plane transmission windows are aligned.
- How does O-RAN handle PRACH IQ data transfer?
- What is Data Flow 1a, 1b, and 1c in U-Plane?
- How is time synchronization distributed in an O-RAN network?
- What is SyncE and how is it used in O-RAN?
- What are the compliant O-RAN timing topology configurations (LLS-C1 through LLS-C4)?
- What are the reference points R1, R2, R3, R4, and Ra in O-RAN?
- What are T12 and T34 delays in O-RAN?
- How does the O-DU function as a Grand Master for synchronization?
- What is the impact of excessive hops/switches on PTP performance?
- What does Full Timing Support mean in O-RAN synchronization?
- What are T-BC and T-TC switches and their relevance to O-RAN?
- What issues may arise if O-DU and O-RU are not properly synchronized?
- What are the main FCAPS functions provided by the O-RAN M-Plane?
- List the architectural models for M-Plane management (Hierarchical vs Hybrid).
- Describe the O-RU bootup and startup sequence.
- What is the function of SDaaS in O-RU integration?
- What information is exchanged during NETCONF capability discovery?
- What is the purpose of “Call Home” in O-RU management?
- How is performance management activated at O-RU startup?
- How is O-RU software upgraded and managed remotely?
- What fault management procedures are performed by O-RU controller?
- What is the role of the management system (NMS/SMO) in hybrid M-Plane models?
- What is the role of the Near-RT RIC in O-RAN?
- What functions are performed by Non-RT RIC?
- What are xApps, and what types of use cases do they support?
- What are rApps and how are they different from xApps?
- Describe the interaction between RIC and the E2 interface.
- How can AI/ML models be integrated into RIC/xApps?
- What is the A1 interface and what information does it convey?
- How does the Near-RT RIC enable closed-loop automation?
- List examples of RIC use cases for performance optimization.
- What is the significance of O-RAN RIC openness for innovation?
- Name the main O-RAN working groups and briefly state their responsibilities.
- What is the focus of WG1 and WG2 in O-RAN?
- Which working group defines the open fronthaul specification?
- Which group leads O-RAN security standardization?
- What is the role of WG6 and WG8?
- How does the O-RAN ALLIANCE ensure global interoperability?
- What are O-RAN blueprints and what purpose do they serve?
- What are the main security risks in O-RAN open interfaces?
- How can O-RAN ensure secure management of O-RUs?
- What are O-RAN’s recommendations for interface authentication and encryption?
- What is the format of IQ data sent from O-DU to O-RU?
- How are scheduling and beamforming commands transmitted?
- What messages are exchanged for LBT (Listen Before Talk) configuration?
- How is uplink and downlink IQ data flow separated in O-RAN?
- How does O-RAN support multi-antenna transmission (MIMO)?
- What timing constraints are required for IQ sample delivery?
- How is data integrity ensured during IQ transport?
- What is the role of data flow S in the S-Plane?
- How are delays monitored and managed across the fronthaul?
- What happens if C-Plane messages do not arrive before U-Plane packets?
- What are the primary performance KPIs monitored in O-RAN?
- How do you verify end-to-end delay between O-DU and O-RU?
- Describe a method to test O-RU interoperability with multi-vendor DUs.
- What is the importance of file and log management in O-RAN?
- How is fault management reported and acted upon?
- How would you identify and resolve a C-Plane packet loss issue?
- How is software rollback handled in O-RAN M-Plane?
- What is the impact of a failed synchronization event in live O-RAN?
- What are the typical alarms generated during O-RU startup?
- How would you monitor and optimize CPU/memory utilization on O-DU?
- How does O-RAN support network slicing?
- What mechanisms are used for isolation between network slices in O-RAN?
- How is dynamic slice management orchestrated in O-RAN?
- What is the significance of open APIs for automation in O-RAN?
- How are configuration and software updates secured?
- What are best practices for logging and audit trails in O-RAN?
- How can unauthorized access to O-RU or O-DU be prevented?
- What is the process for key rotation in O-RAN deployments?
- How is resource allocation optimized in a multi-slice scenario?
- What are potential attack vectors unique to O-RAN architecture?
- What is OpenXhaul and how does it relate to O-RAN?
- How does O-RAN enable private 5G networks?
- What are the benefits of using COTS hardware in O-RAN deployments?
- What is the impact of O-RAN on edge computing?
- What role does O-RAN play in IoT and vertical industry support?
- How is AI/ML expected to evolve in the O-RAN ecosystem?
- What is the significance of RAN virtualization in O-RAN?
- How can O-RAN be used for Open RAN as-a-Service (O-RANaaS)?
- How are new features standardized and rolled out in the O-RAN Alliance?
- What trends are expected in O-RAN with the move towards 6G?
- How would you troubleshoot a failed O-RU software upgrade?
- If an O-DU loses synchronization with its O-RUs, what steps do you take?
- How do you handle a sudden spike in fault alarms on the M-Plane?
- How would you integrate a new vendor’s O-RU into a running O-RAN network?
- What’s the process for validating a new xApp in the Near-RT RIC?
- How would you optimize fronthaul bandwidth in a dense urban deployment?
- What would you do if two O-DUs report duplicate O-RU connections?
- Describe a real-world scenario where RIC can prevent network outage.
- How would you verify multi-tenancy operation in an O-RAN deployment?
- How can you use logs to identify the cause of a cell outage in O-RAN?
- What are the main challenges of integrating multi-vendor O-RAN components?
- How is software versioning managed in a multi-vendor O-RAN?
- What tools or practices help ensure cross-vendor interoperability?
- How does O-RAN address localization requirements for global deployments?
- What are typical interoperability issues faced in real networks?
- How do operators validate O-RAN compliance for new hardware/software?
- What is the significance of open testing and certification for O-RAN?
- What role does the O-RAN Software Community play?
- How do O-RAN standards accommodate region-specific spectrum/band requirements?
- How does O-RAN enable plug-and-play RAN elements?
- How could O-RAN principles be applied to non-terrestrial networks?
- What are the main bottlenecks to full O-RAN disaggregation?
- What is the potential of using blockchain for security in O-RAN?
- How does O-RAN need to evolve for real-time, ultra-reliable low-latency use cases?
- What impact will quantum-safe cryptography have on O-RAN?
- How can O-RAN enable more sustainable, energy-efficient networks?
- What are research challenges in O-RAN AI/ML integration?
- What will be the effect of zero-touch automation on O-RAN operations?
- How could O-RAN be extended to support NTN, V2X, or industrial 6G?
- What are the challenges of integrating O-RAN with cloud-native cores?
- What skills are critical for an engineer working in O-RAN development?
- How do O-RAN projects differ from traditional RAN in team structure?
- What are the most common mistakes when configuring O-RAN networks?
- How should an operator approach O-RAN migration from legacy RAN?
- What open-source projects should a new O-RAN developer study?
- What certifications or communities support O-RAN career development?
- How do you keep up with evolving O-RAN standards?
- What is your opinion on O-RAN as a path to 6G?
- What are the main risks of adopting O-RAN early?
- What’s your vision for the future of Open RAN in the telecom industry?
- What is the first step when deploying a new O-RU?
- Name two xApps use cases for RIC.
- What is the default protocol for O1 interface management?
- What’s the most critical KPI for fronthaul performance?
- Which split option is best for rural deployments and why?
- What is the main advantage of O-RAN for greenfield operators?
- How does O-RAN support massive MIMO deployments?
- In one line, why does O-RAN matter for 5G?
- What’s the biggest technical challenge for O-RAN in 2025?