Integrating YANG Configuration and Management into an Abstraction and Control of TE Networks (ACTN) System for Optical Networks

Introduction Abstraction and Control of Traffic Engineering Networks (ACTN) is an architecture that simplifies and optimises the management and control of network resources to deliver connectivity services in Traffic Engineering (TE) networks. ACTN abstracts and controls TE resources to enable end-to-end service provisioning and management across multiple network domains. It provides a way to orchestrate and automate the management of network resources, including connectivity and bandwidth, to meet the requirements of specific services or applications. ACTN in an optical network leverages SDN concepts to achieve its objectives. By applying SDN principles, such as centralised control and programmability, to the transport layer, ACTN enables efficient orchestration and service provisioning in a multi-domain environment. ACTN adds a higher-level framework and management capabilities specifically tailored for TE transport networks, including the abstraction of network resources, service provisioning, and resource optimisation. The term FCAPS is used in network management and stands for Fault, Configuration, Accounting, Performance, and Security. It is a widely accepted framework that documenting different aspects of network management. FCAPS is a framework that categorises different aspects of network management and provides a structured approach to managing and maintaining networks, addressing various operational and maintenance areas. While ACTN primarily deals with the abstraction and control of TE networks for service provisioning, FCAPS covers broader aspects of network management. In practice, while ACTN provides a suitable architecture for requesting and monitoring connectivity services, operators would also like to leverage the FCAPS framework for specific operational tasks and management activities. ACTN and FCAPS are not mutually exclusive, and this document explains how FCAPS can be integrated into the ACTN architecture as applied to optical networks. It considers which elements of IETF work can be used, and what new work is needed. This enhanced ACTN architecture is known as ACTN Fine-Grain Network Management (ACTN FGNM). It provides an evolution path for FCAPS OSS functions from Common Object Request Broker Architecture (CORBA) [CORBA] interfaces and the MTOSI architecture, to IETF YANG-based models and RESTful APIs.

FCAPS Transport Network Management Approaches ITU-T G.805 specifies the architecture and framework for the management of transport (i.e., sub-IP) networks. G.805 provides guidelines and principles for managing network resources and services in a coordinated and efficient manner. The TM Forum (TMF) has developed its own set of standards and frameworks for managing telecommunications networks and services. Specifically, the TMF developed the Telecommunications Management Network (TMN) model and informed the ITU-T M.3060 to align with G.805. TMN is a framework that defines a comprehensive set of management functions and interfaces for network operations and service management, that is, FCAPS. More recently, ITU-T M.3041 introduced a framework for smart operation, management, and maintenance (SOMM). In M.3041 provides the characteristics, scenarios, and the functional architecture of SOMM to support service operation, network management, and infrastructure maintenance for both traditional physical networks and for software-defined networking, and network function virtualisation (non-SDN/VFN), and SDN/NFV aware networks. This document shows how the ACTN architecture can accommodate the principles of G.805 and M.3041 to include FCAPS capabilities. It outlines existing IETF mechanisms, protocols and data models, and indicates requirements where gaps exist.

Configuration Management MTOSI [MTOSI] is a standard in the telecommunications industry that provides a common framework for operations support systems (OSS) to interact with various network elements and technologies. It defines a set of standardized interfaces and protocols to enable the integration of different OSS components. It contains several capabilities and key features:

Service Management: It focuses on service management, allowing operators to efficiently provision, activate, and manage services on the network;
Interoperability: MTOSI promotes interoperability between different vendors' OSS components, reducing the complexity of integrating heterogeneous network elements;
Common Data Model: It defines a common data model for information exchanged between OSS components, ensuring consistency and accuracy in operations.

These features must be introduced into ACTN as ACTN FGNM, to enable automation of operations, which is crucial for managing large, multi-technology, complex, telecommunications networks. Increasingly, network OSSes will require atomic-level views of network devices and interfaces, instead of only abstracted views and interactions. This will allow ACTN-based systems to leverage inventory management, device-level and interface-level views, and network configuration operations, via RESTful APIs instead of legacy CORBA-based APIs.

Service Assurance Service Assurance refers to the activities and processes that ensure the quality, availability, and performance of services delivered by a network. It monitors and manages the end-to-end service experience, and meets Service Level Agreements (SLAs) and customer expectations. By applying RESTful FCAPS functions to the ACTN framework, network operators and service providers can address different aspects of network management to support Service Assurance. This helps them detect and resolve faults, manage configurations, track resource usage, optimise performance, and enhance security, all of which contributes to delivering reliable and high-quality services to customers. Not all Service Assurance requirements can be provided via existing ACTN YANG models. Fine-grain detail may also be required, supplementing abstract resource models with inventory-based models [I-D.ietf-ccamp-network-inventory-yang]. This would provide an atomic-level view of network devices and components, instead of only abstracted views. Note that not all FCAPS functions require fine grain views and control, a mix of abstracted and detailed views will sometimes be needed.

Motivation and Scope Operators who manage optical transport networks can leverage ACTN for resource abstraction and service provisioning. At the same time, they can utilise the G.805 architecture and the TMN model to establish effective network management practices, which will facilitate service assurance. Combining the two management approaches aligns with best-practice industry standards and allows adopting emerging ACTN-based abstraction and control techniques. This document studies the FCAPS requirements in the context of ACTN functional components. It analyses the ACTN interfaces from a management operations perspective. It identifies suitable IETF data models that meet FCAPS requirements that can be utilised in the ACTN architecture to support optical transport networks. Gaps and requirements are identified where necessary so additional models may be developed.

Extending the ACTN Architecture to Include FCAPS shows the ACTN architecture from enhanced to provide FCAPS support. The Customer Network Controller (CNC), Multi-domain Service Coordinator (MDSC), and Provisioning Network Controller (PNC) are functional components of ACTN, as described in RFC 8453. There are two ACTN interfaces between the components: the CNC-MDSC Interface (CMI) and the MDSC-PNC Interface (MPI). In ACTN, the CMI and MPI are realised using a combination of IETF data models.

The ACTN Architecture Enhanced for FCAPS shows the ACTN functional components as described in , but also introduces some common management system components. The Operational Support System (OSS) is the overarching management component that the operator uses to coordinate customers, services, and the network, and to apply policies across the network. The Network Management System (NMS) allows an operator to manage a network or set of network elements as a single unit. At the same time, the Element Management System (EMS) applies configuration and management to individual network elements. As described in , the function of the PNC may be provided by an NMS or an EMS. Thus, shows the PNC overlapping with the NMS/EMS. To avoid confusion between the three possible components (NMS, EMS, PNC) that might all be used to operate the devices in the network, this document groups all of their function together and uses the term Domain Controller. In a conventional management system, the OSS uses an interface with the Domain Controller to exchange FCAPS information. This interface has previously been based on CORBA/XML. Furthermore, in an ACTN system, the OSS is likely the point of origin for policy instructions that guide the MDSC in how it orchestrates customer service requests and configures the network. In the MPI is used by the MDSC to instruct the PNCs about how the network must be configured to deliver the customers' services. The MPI also reports to the MDSC on the status of provisioning commands and the availability of network resources. However, up to now, the MDSC has had no visibility into the majority of the FCAPS functions and has, therefore, had limited reactive and proactive abilities. Instead of only using abstracted Tunnel and Topology YANG models, the capability to support network inventory and device models is required. Facilitating much more detailed modeling, and configuration management of network resource information. This document examines how the MPI may be enhanced with extensions that utilise current YANG models, such as inventory, and future YANG-based data models to deliver extensions that provide RESTful FCAPS support.

Functionality at the MPI This section describes the MPI as specified before the addition of FCAPS capabilities.

Data Models at the MPI lists the data models that can be used at the MDI for abstraction and control of underlying optical networks.

ACTN MPI YANG Models

Abstraction and Control at the MPI The abstraction of TE modeling is described in Section 3 of . The major objects that are modeled include TE topology, TE node, TE link, TE Link Termination Point (LTP), TE Tunnel Termination Point (TTP). Also included in the modeling are transitional TE link, TE node connectivity matrix, and TTP Local Link Connectivity List to describe the multiplexing relationship of links. These TE concepts are generic, but they are also applicable within an optical network. The MPI deals in abstracted TE network concepts and so can be realised using the YANG models listed in to expose the TE modeled objects that can be enhanced using YANG model augmentations to make them specific to optical technologies.

Introduction to FCAPS

Functionalities Covered by FCAPS Although the building blocks of FCAPS are Fault, Configuration, Accounting, Performance, and Security, important functions for integration with an ACTN system are Configuration and Performance, which are underpinned by Inventory Management. Inventory Management describes all objects involved in the network, including hardware resources (such as network elements, chassis, slots, boards, ports, optical modules, and cables, etc.) and logical resource objects used for service provisioning. The basic Configuration requirement in ACTN is to configure end-to- end paths across the transport network based on the requirements of users. Alarm Management. When a network is running, the Domain Manager collects alarm information from devices or processes connection- related alarms and reports the alarms to the OSS of operator. So that Operations and Management engineers can detect and rectify network faults in time. The main functionalities include alarm retrieval, alarm handling, and alarm control. Performance Monitoring. Based on some Operations and Management requirement scenarios, engineers need to collect and monitor performance data from certain physical devices or logical objects to identify the status of the network. The interfaces of Performance Management include performance monitoring control, performance information retrieval, and threshold crossing alert control.

Abstract Control and Fine-Grain Network Management for ACTN Abstract Control represents the high-level strategic view and objectives, while Fine-Grain Network Management represents the detailed operational tasks and activities that support the strategic objectives. Both levels are important for effective management and control within the operator network. Abstract Control is often mapped to G.805 objects. An Abstract Control object can also be mapped to several Fine-Grain Network Management objects. Therefore, we should not see these concepts as mutually exclusive, but instead as necessary approaches to be combined for holistic control and operational management of ACTN- based network infrastructures. In the context of ACTN, MPI is a concept and a set of mechanisms within ACTN that enables the interconnection of services across multiple domains or administrative boundaries. The MPI addresses the challenge of interconnecting services across multiple administrative domains. It provides a mechanism to coordinate and manage the service delivery between domains while ensuring end-to-end service continuity and quality. As highlighted earlier in this document FCAPS capabilities are also vital for smooth operation and troubleshooting of ACTN-based services. It is expected that FCAPS capabilities will require Fine- Grained Network Management Functions.

Abstract Control and Fine-Grain Network Management Functions for the MPI The Fine-Grain Network Management Functions can be categorised as follows. Several aspects of there functions already exist in the MDSC in the ACTN architecture, and are accessed via the MPI. Others may be added to the MPI in the future. Service Provisioning: This involves the detailed provisioning and activation of services. This includes path computation, configuring service parameters, policy management, allocating resources, and ensuring proper service activation and deactivation. Network Performance Monitoring: This encompasses monitoring and analysing network performance. It involves collecting and analysing performance metrics such as latency, jitter, packet loss, and throughput to identify and resolve performance issues promptly. Fault Detection and Alarm Management: This includes advanced fault detection mechanisms to identify and troubleshoot network issues quickly. It involves monitoring network elements, analysing alarms and events, and performing fault localisation and isolation to expedite problem resolution. Security Management: This covers the management of security measures within the telecommunications network. It involves activities such as access control, authentication, encryption, intrusion detection, and vulnerability management to ensure network security and protect against threats. Service Level Agreement (SLA) Management: This involves tracking service performance against SLA targets, generating SLA reports, and taking corrective actions to meet or exceed customer expectations. Capacity Planning: This encompasses detailed capacity planning activities to ensure optimal resource utilisation and meet future demands. It involves analysing traffic patterns, forecasting capacity requirements, and implementing capacity expansion strategies.

Fine-Grain Network Management Interfaces Several legacy Fine-Grain Network Management interfaces, such as CORBA, exist to facilitate the precise control and management of network elements and services. These interfaces enable communication and interaction between different systems, devices, and management platforms:

Command Line Interface (CLI)
Simple Network Management Protocol (SNMP)
CORBA/XML

New interfaces and data models have been developed that support Fine-Grain Network Management functions. These models are written in YANG, and the interfaces use NETCONF and RESTCONF, the latter also providing RESTful API functions.

Fine-Grain Network Management Data Models As noted in , new or enhanced data models may be required for Fine-Grain Network Management in ACTN-based optical networks. shows a functional architecture for YANG control in an ACTN system enhanced with FGNM. The existing ACTN YANG models provide access to network devices through topology models that map to inventory and thus to configuration of network devices. The old MTOSI approach provides access to inventory and device configuration. The FGNM additions to ACTN retrieve information from the inventory including performance information viewed through the lens of topology. It also allows direct manipulation of devices through configuration of inventory items in a mirror of the MTOSI function. Lastly, fault and alarm information that is generated in respect of the inventory may be delivered direct to the FGNM system or may be correlated before being reported as incidents.

Functional Model of ACTN with FGNM Work in the IETF exists to provide optical interface configuration, resource monitoring, telemetry data, alarm and incident monitoring, inventory, life cycle management, service assurance, and asset management. This existing IETF work includes:

Incident Management for Network Services
A YANG Data Model for Network Hardware Inventory
Service Assurance for Intent-based Networking Architecture
YANG Modules for Service Assurance
A Data Manifest for Contextualized Telemetry Data
Asset Lifecycle Management and Operations Problem Statement
A YANG Data Model for Optical Resource Performance Monitoring
A YANG model to manage the optical interface parameters for an external transponder in a WDM network
A YANG Data Model for Client Signal Performance Monitoring

This section will expand the list of the available IETF YANG data models that could provide Fine-Grain Network Management functionality, in the context of ACTN, specifically the MDI.

Fine-Grain Network Management Example Editors note: An example of Fine-Grain Network Management of an optical network using the ACTN architecture will be provided in future versions of this document.

Manageability Considerations TBD

Security Considerations Security requirements will require that measures and protocol security are applied to ensure the confidentiality, integrity, and availability of information and resources within the context of an ACTN FGNM-based OSS. Key aspects of ACTN FGNM security, will require:

Authentication: The process of verifying the identity of an ACTN user, system, or device. Security includes mechanisms to authenticate users and systems before allowing them to access sensitive resources or perform certain operations;
Authorization: Once a user or system is authenticated, authorization determines what actions or resources they are allowed to access. MTOSI security mechanisms define roles, permissions, and access controls to ensure that only authorized entities can perform specific tasks;
Data Encryption: Security may employ encryption techniques to protect sensitive data as it is transmitted over the ACTN-based OSS network. This prevents unauthorized access or interception of information;
Secure Communication Protocols: The use of secure communication protocols, such as HTTPS (HTTP over SSL/TLS) or other cryptographic protocols, ensures that data exchanged between ACTN components remains confidential and secure;
Secure Data Storage: Security measures are put in place to protect data stored within the ACTN environment. This includes encryption of stored inventory, device and service data, access controls, and regular security audits;
Auditing and Logging: This includes the capability to record and monitor ACTN-based activities within the OSS. Audit logs provide a record of who accessed what resources and when, which is crucial for investigating security incidents or compliance with regulations;
Intrusion Detection and Prevention: Systems may have mechanisms in place to detect and respond to unauthorized access attempts or suspicious activities. Intrusion detection systems (IDS) and intrusion prevention systems (IPS) can play a role in ACTN-based security;
Vulnerability Management: Regular security assessments and vulnerability scans help identify and address potential weaknesses in the ACTN environment;
Security Policies and Procedures: Clear security policies and procedures should be established and communicated to all stakeholders. This ensures that everyone understands their responsibilities in maintaining the security of the ACTN system;
Incident Response: Security should include plans and procedures for responding to security incidents, including steps for containment, investigation, mitigation, and recovery

Overall, security is crucial for maintaining the integrity and reliability of ACTN FGNM operations and support systems, especially in an environment where sensitive customer data and critical network resources are involved.

IANA Considerations This document makes no requests for IANA action.

Acknowledgements Thanks to Chaode Yu for discussions that enhanced the material in this document.