O-RAN ALLIANCE has released another set of technical specifications for open and intelligent RAN published since November 2021. This batch of specs, together with the batch published in July 2021, complete the O-RAN Release 002, the first O-RAN Release focusing on enabling Open Intelligence. To access the O-RAN specifications, please visit our website.
This batch include 4 new titles comprising:
Another 36 technical documents bring extensions and new features to the existing specifications. A brief overview of all 40 specifications is provided below.
4 specifications published since November 2021:
The O-RAN Architecture Description document specifies the overall architecture of O-RAN. It describes all the O-RAN functions and relevant interfaces that connect these functions. This version clarifies how R1 interface enables rApps to obtain information and trigger actions through the SMO interfaces towards O-RAN functions. It includes the ‘Open FH M-Plane’ interface (between SMO and O-RU) to the functional architecture of the Non-RT RIC. A section on the ‘UE Associated Identifier’ for correlating UE identities across all O-RAN logical functions has been added. It introduces the ‘O-Cloud Notification’ interface to enable O-RAN functions to receive critical information from the cloud infrastructure. The O-RAN security architecture consisting of ‘Threat Analysis’, ‘Attach Surfaces’, and ‘Security Protocols’ is another notable feature of this version.
This document describes potential O-RAN use cases at a very high level, emphasizing how the use case is enabled by the O-RAN architecture along with basic input data expectations and resulting actions. This version includes addition of a new use case (“Integrated SON Function”) and updates to NSSI resource optimization use case.
This document describes selected O-RAN use cases in further details to facilitate relevant O-RAN Work Groups to define requirements for associated O-RAN functions and interfaces. This version includes updates to NSSI resource optimization use case.
This document describes O-RAN slicing related use cases, requirements, and architecture. Along with requirements and a reference slicing architecture, slicing related impact to O-RAN functions and interfaces is also captured. This version includes updates to NSSI resource optimization use case and a new Annex section for slicing terminology awareness.
3 specifications published since November 2021:
The R1 GAP Specification has summarized the R1 Interface Specification Objectives and Specified the Principles and procedures for:
This initial version of the A1 Test Specification includes conformance tests for both the Non-Real-Time RIC and the Near-Real-Time RIC for the policy related services on the A1 interface.
This document describes O-RAN Non-RT RIC use cases in detail including the required datasets, the workflows, and the interactions within and outside of Non-RT RIC with other O-RAN components. As a result of the use case analysis, this specification captures the requirements imposed by these use cases on the Non-RT RIC architecture, A1 and R1 interfaces as well. This version includes the addition of NSSI resource optimization use case and updates to RAN Slice SLA assurance use case.
6 specifications published since November 2021:
This specification describes the functional architecture of O-RAN Near-Real-Time RAN Intelligent Controller (Near-RT RIC), and the Stage-2 designs of Near-RT RIC APIs between Near-RT RIC platform and xApps. This version introduces a new internal function “xApp repository function”, additional Near-RT RIC API designs, and revisions related to the management and orchestration of xApps.
A set of three E2 specifications present corrections and minor enhancements to their corresponding v2.0. Support of E2 removal, clarifications on multiple TNLA handling, and definition of UE identity over the E2 interface are provided.
The newer version of E2SM-KPM includes additional network measurements related to slicing and new report styles for group of UEs, compared to its v2.0.
The newer version of E2SM-RC contains clarifications and small corrections to its v1.0.
4 specifications published since November 2021:
This specification defines the Control Plane, User Plane and Synchronization Plane of the Open Fronthaul Interface. Version 8.0 contains main changes in the following areas:
This spec brings essential upgrade of YANG models for Management Plane specification in v7.0.
This document describes O-RAN Open Fronthaul M-Plane Specification, which defines the Management Plane of the Open Fronthaul Interface as well as the associated YANG models. This version contains main changes in the following areas:
This document describes O-RAN Open Fronthaul IOT Specification, which defines tests to validate the ability for O-DU and O-RU equipment to operate together using the Open Fronthaul Interface. This version delivers:
5 specifications published since November 2021:
The scope of WG5 IOT spec is to specify interoperability tests for RAN Node from different vendors implemented in accordance with the WG5 C-plane and U-plane profiles.
This version of the IOT spec focuses on:
Main Updates compared to v2.0 include:
The scope of U-Plane profile spec is to further clarify the expected behavior (still within the scope of the 3GPP specifications) of each RAN node, e.g. usage of IEs for each use case, general behavior of each node, etc. U-Plane profile specification contains profiles of X2/F1/Xn U-Plane procedure for EN-DC use cases, NR-SA use cases and NR-DC use cases.
Main Updates compared to v4.0 include 3GPP baseline version uplifted to Rel-16.
The scope of C-Plane profile spec is to further clarify the expected behavior (still within the scope of the 3GPP specifications) of each RAN node, e.g. usage of IEs for each use case, general behavior of each node, etc. C-Plane profile specification contains profiles of X2/F1/Xn C-Plane procedure for EN-DC use cases, NR-SA use cases and NR-DC use cases.
Main Updates compared to v5.0 include:
The scope of O-DU O1 Interface specification is to specify the interface that links O-DU to the Service Management and Orchestration (SMO) framework. It is focused on O-DU management operations, performance counters, fault supervision, software management, synchronization management, and configuration parameters for O-DU. Compared to v2.0, this version includes:
The scope of O-CU O1 Interface specification is to specify the interface that links O-CU-CP and O-CU-UP to the Service Management and Orchestration (SMO) framework. It is focused on O-CU management operations, performance counters, fault supervision, software management, and configuration parameters for O-CU. Compared to v1.0, this version includes:
5 specifications published since November 2021:
This document specifies the general aspects and principles associated with the O2 interface. This version introduces the O-Cloud Provisioning concepts, the O-Cloud Performance concepts, and it also provides further clarification about the O2 DMS interface, i.e. an O-Cloud might have its own specific O2dms service API profile.
This specification details the AAL specification for inline accelerators supporting the High-PHY acceleration profiles for all uplink and downlink channels. It contains the description of the interface, information models and requirements to implement an AALI, for the AAL_DOWNLINK_High-PHY and AAL_UPLINK_High-PHY profiles.
This document specifies use cases and associated requirements for the management and orchestration of O-RAN virtualized RAN. This version is retitled “Cloudification and Orchestration Use Cases” and incorporates use case additions to support Functional Status Query, Fault, Performance and VLAN Management Use Cases.
O-RAN AAL enables decoupling of RAN software from hardware by defining abstract interfaces for accelerated RAN functions to allow a RAN software implementation to work with different accelerator implementations. The AAL GA&P defines the high-level architecture and accelerator profile definitions for the AAL. This version of the document adds updates to support inline High-PHY profiles including AALI definitions, general interface principles, and the introduction of aggregated Downlink and Uplink High-PHY profiles.
This specification outlines the infrastructure management services of the O2 interface. This version brings clarification about the attributes of the O-Cloud, and it synchronizes the Infrastructure Inventory figure with the descriptions in the related table.
2 specifications published since November 2021:
The O-RAN Stack Interoperability Test Specification provides interoperability test cases of O-CU and O-DU for end to end call flows. This version contains the following updates:
The O-RAN Base Station O-CU and O-DU Architecture and APIs specification provides the reference architecture, design and APIs for O-CU and O-DU implementation. The specification details the functional block of O-CU and O-DU, including messages across L1, L2 and L3 layers and call flows. This version adds the following key updates:
3 specifications published since November 2021:
This document describes best practices for O-RAN fronthaul transport based on WDM technology. This version contains the following enhancements:
The document is intended to describe best practices for O-RAN transport Network Element (TNE) management interfaces. This version adds:
The document describes best practices for O-RAN Architecture and Solution for X-haul timing and synchronization. This version adds content for:
3 specifications published since November 2021:
The O-RAN OAM Architecture identifies management services, managed elements, functions and applications supported in O-RAN, including the interworking between SMO and O-RAN O-Cloud management components. Requirements are derived from end-to-end OAM use cases, including the initial provisioning of O-RAN service across VNFs and PNFs and the collection of measurement data. This version includes:
The O1 interface defines management services supported by O-RAN managed elements and provides an interface between these managed elements and the SMO. This version includes:
This version of Information Model and Data Models spec includes:
1 specifications published since November 2021:
This document describes the certification and badging processes and associated detail technical procedures that Open Testing and Integration Centre (OTIC) and various other testing entities should adopt. This version brings forth the following:
4 specifications published since November 2021:
This document specifies the Security Requirements per O-RAN Interface and per O-RAN component and adds transversal requirements and Software Bill of Material (SBOM) guidelines. This version includes:
This document specifies security protocols to be used for O-RAN compliant implementation. It captures implementation requirements for SSH, IPSec, DTLS, TLS 1.2, TLS 1.3 and NETCONF support over secure Transport. This version adds mandatory support for TLS 1.3.
This document provides description of the Security Tests which validate security functions, configurations and security protocols requirements. It contains sets of tests to validate proper implementations of security protocols as defined in the O-RAN Security Protocols Specifications (SSH, TLS, DTLS, IPSec). Tests for O-RAN components related to transversal requirements defined in O-RAN Security Requirements specification are also specified: Service Enumeration, Password-based Authentication protection against brute-force, Unauthorized password reset, Secure password policy enforcement, Robustness against volumetric DDoS attacks. Security evaluation of robustness of OS and Applications of O-RAN components are also specified with system vulnerability scanning.
This document specifies the O-RAN Security Threat Modeling and Remediation Analysis. It identifies assets to be protected, analyzes the O-RAN components for vulnerabilities, examines potential threats associated with those vulnerabilities and their mapping to specific O-RAN identified assets. It provides security principles, which stakeholders should address when building a secure end-to-end O-RAN system. It brings a risk assessment based on ISO 27005 standard that aims to assess the criticality of threats based on their potential impacts. This version adds further details and new threats related to the Fronthaul Control and Synchronization planes interface.
Chih-Lin I and
Sachin Katti
