# Daily Report day 8
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29/07/2021
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## 1. Aspects : RAN Intelligent Controller (RIC), Network Management and Security

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### A. RAN Intelligent Controller (RIC)

#### Near Real-Time RAN Intelligent Controller (Near-RT RIC)
Near Real-Time RAN Intelligent Controller (Near-RT RIC) is a near‐real‐time, micro‐service‐based software platform for hosting micro-service-based applications called xApps. They run on the near-RT RIC platform. The near-RT RIC software platform provides xApps cloud-based infrastructure for controlling a distributed collection of RAN infrastructure (eNB, gNB, CU, DU) in an area via the O-RAN Alliance's E2 protocol ("southbound"). As part of this software infrastructure, it also provides "northbound" interfaces for operators: the A1 and O1 interfaces to the Non-RT RIC for the management and optimization of the RAN. The self-optimization is responsible for necessary optimization-related tasks across different RANs, utilizing available RAN data from all RAN types (macros, Massive MIMO, small cells). This improves user experience and increases network resource utilization, key for consistent experience on data-intensive 5G networks.
RIC Near-Real Time (<500ms)
- Radio Resource Management (RRM)
- QoS management
- Connectivity Management
- Seamless Handover Control

#### Non-Real-Time RAN Intelligent Controller (Non-RT RIC)
Non-Real-Time RAN Intelligent Controller (Non-RT RIC) functionality includes configuration management, device management, fault management, performance management, and lifecycle management for all network elements in the network. It is similar to Element Management (EMS) and Analytics and Reporting functionalities in legacy networks. All new radio units are self-configured by the Non-RT RIC, reducing the need for manual intervention, which will be key for 5G deployments of Massive MIMO and small cells for densification. By providing timely insights into network operations, MNOs use Non-RT RIC to better understand and, as a result, better optimize the network by applying pre-determined service and policy parameters. Its functionality is internal to the SMO in the O-RAN architecture that provides the A1 interface to the Near-Real Time RIC. The primary goal of Non-RT RIC is to support intelligent RAN optimization by providing policy-based guidance, model management and enrichment information to the near-RT RIC function so that the RAN can be optimized. Non-RT RIC can use data analytics and AI/ML training/inference to determine the RAN optimization actions for which it can leverage SMO services such as data collection and provisioning services of the O-RAN nodes.
RIC Non-Real Time (>500ms)
- service and policy management
- RAN analytics
- Model-training for Near-RT RAN functional

#### QoS Mechanisms
Traffic handling (In-traffic) mechanism
- clasify, handle, police, and monitor the packets across the network
- main mechanisms:
- classification
- traffic policing
- packet scheduling
- channel access

bandwidth management (Out-of-traffic) mechanisms
- manage the network resources (e.g., bandwidth) by coordinating and configuring network devices traffic handling mechanisms.
- main mechanism:
- resource reservation signaling
- admission control

#### Radio Resource Management (RRM)
General functionalities of RRM are:
- radio resource allocation (scheduling)
- call admission control
- load balancing (traffic steering)
- mobility (handover)
- multi-connectivity
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### B. Service Management and Orchestration (SMO)
Service Management & Orchestrator (SMO): The component that oversees all the orchestration aspects, management and automation of RAN elements. It supports O1, A1 and O2 interfaces.
As mentioned, the non real-time RIC exists within the SMO framework, which is a combination of several management services. It is capable of going beyond supporting a RAN, but also can conduct network core management, transport management, and network slicing management.
Outside of the non real-time RIC, the key aspects of the SMO include managing and orchestrating the open cloud (O-Cloud) as well as containing the FCAPS services for the O-RAN network elements. FCAPS stands for fault, configuration, accounting, performance, security; which are various management categories for maintaining and securing the O-RAN virtual network functions (VNFs).
The O-Cloud is a collection of physical RAN nodes that host the RICs, CUs, and DUs; the software components such as the operating systems and runtime environments; and the SMO. To be clear, the SMO is managing and orchestrating the O-Cloud from within.

#### Network Management

#### Management and Orchestra
Management and orchestration of 5G networks and network slicing is a feature that includes the following work items:
- management concept and architecture
- provisioning
- network resource model
- fault supervision
- assurance and performance management
- trace management
- virtualization management aspects

The management concept, architecture and provisioning are defined in TS 28.530, 531, 532, 533.

#### O-RAN Security Protocol
SSH
- SSHv2

Transport Layer Security (TLS):
- TLS 1.2, 1.3

#### O-RAN SMO Interfaces
The key O-RAN SMO interfaces are:
* O1: Interface between management entities in Service Management and Orchestration Framework and O-RAN managed elements, for operation and management, by which FCAPS management, software management, and file management shall be achieved.
* O2 (previously O1*): Interface between Service Management and Orchestration Framework and Infrastructure Management Framework supporting O-RAN virtual network functions.
* A1: Interface between non-RT RIC and near-RT RIC. Over this interface non-RT RIC performs policy management, enrichment information and AI/ML model updates on the near-RT RIC.
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### C. Open Standards for Interfaces

#### Open Fronthaul Interface
The open fronthaul interface connects the O-DU and open radio unit (O-RU). It breaks down into the management plane (M-Plane) and the control user synchronization plane (CUS-Plane). The M-Plane connects the O-RU to the O-DU, and only optionally connects the O-RU to the SMO. The O-DU uses the M-Plane to manage the O-RU, while the SMO can provide FCAPS services to the O-RU.

#### A1 Interface
The A1 interface enables communication between the two RICs and supports policy management, data transfer, and machine learning management. The data, actually called enrichment information, is specifically for assisting the model training for the AI and machine learning in the near real-time RIC.

#### O1 and O2 Interfaces
The O1 interface connects the SMO to the RAN managed elements. These include the near real-time RIC, O-CU, O-DU, O-RU, and the open evolved NodeB (O-eNB). The O-eNB is the hardware aspect of a 4G RAN. The management and orchestration functions are received by the managed elements via the O1 interface. The SMO in turn receives data from the managed elements via the O1 interface for AI model training.
The O2 interface is how the SMO communicates with the O-Cloud it resides in. Network operators that are connected to the O-Cloud can then operate and maintain the network with the O1 or O2 interfaces by reconfiguring network elements, updating the system, or upgrading the system.

#### X2 and Xn Interface
The X2 interface is broken up into the X2-c and X2-u interfaces, where the former is for the control plane and the latter is for the user plane. Both are originally designed by 3GPP for sending information between a 4G network’s eNBs, or between an eNB and a 5G network’s en-gNB. In the O-RAN Alliance’s documentation, the interface has the same principles and protocols. In the above image, Both of the X2 interfaces enter from outside the architecture, showing that they are incoming to another deployment. The Xn, NG, F1, and E1 interfaces are all also adopted from 3GPP standards.
The Xn interface is also broken into control and user subtypes — Xn-c and Xn-u. They transfer control and user plane information between next generation NodeBs (gNBs), between ng-eNBs (4G nodes capable of connecting to a 5G core), or between the two different types.

#### NG Interface
The NG control and user plane interfaces connect an O-CU control plane (O-CU-CP) and O-CU user plane (O-CU-UP) to the 5G core. The control plane information goes to the 5G access and mobility management function (AMF), which receives connection and session information from the user equipment. The user plane information goes to the 5G user plane function (UPF), which handles many aspects of routing, forwarding, and tunneling.

#### F1 Interface
The F1 interface, again broken into control and user plane subtypes, connects the O-CU-CP and O-CU-UP to the O-DU. It exchanges data about the frequency resource sharing and other network statuses. One O-CU can communicate with multiple O-DU via F1 interfaces.

#### E1 and E2 Interfaces
The last of the 3GPP-based interfaces is the E1 interface. It connects the two disaggregated O-CU user and control planes. It transfers configuration data and capacity information between the two O-CU planes. The configuration data ensures the two planes can interoperate. The capacity information is sent from the user plane to the control plane and includes the status of the user plane.
The near real-time RIC in the open RAN architecture connects to the O-CU, O-DU, and O-eNB with the E2 interface. These elements combined make the E2 node. An E2 node can only connect to one near real-time RIC, but one of those RICs can connect to multiple E2 nodes. The protocols that go over the E2 interface are only control plane protocols. The protocols are for controlling and optimizing the E2 node elements and the resources they use. Again, data collected is returned to the RIC over the interface.
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## 2. Summary
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Near Real-Time RAN Intelligent Controller (Near-RT RIC) is a near‐real‐time, micro‐service‐based software platform for hosting micro-service-based applications called xApps.
Non-Real-Time RAN Intelligent Controller (Non-RT RIC) functionality includes configuration management, device management, fault management, performance management, and lifecycle management for all network elements in the network.
Service Management & Orchestrator (SMO): The component that oversees all the orchestration aspects, management and automation of RAN elements. It supports O1, A1 and O2 interfaces.
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## 3. Comment
The O-RAN Alliance’s RIC has two forms, a non real-time RIC and a near real-time RIC. The two get their names from their response times. The non real-time RIC is a logical function, meaning it is software and not hardware. It exists in the service management and orchestration (SMO) system.

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# <center>Discussion with Team</center>

1. Discuss about final project
2. Prepare Presentation