NMOP O. Havel Internet-Draft B. Claise Intended status: Informational Huawei Expires: 4 January 2025 O. G. D. Dios Telefonica T. Graf Swisscom 3 July 2024 Digital Map: Concept, Requirements, and Use Cases draft-havel-nmop-digital-map-concept-00 Abstract This document defines the concept of Digital Map, explains its connection to the Digital Twin, and identifies a set of Digital Map requirements and use cases. The document intends to be used as a reference for the assessment effort of the various topology modules to meet Digital Map requirements. Discussion Venues This note is to be removed before publishing as an RFC. Source for this draft and an issue tracker can be found at https://github.com/OlgaHuawei/draft-havel-nmop-digital-map-concept/. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 4 January 2025. Havel, et al. Expires 4 January 2025 [Page 1] Internet-Draft Digital Map Concept & Needs July 2024 Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Digital Twin Overview . . . . . . . . . . . . . . . . . . 3 1.2. Digital Map . . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Digital Map as a Prerequisite for Digital Twin . . . . . 4 1.4. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Sample Digital Map Use Cases . . . . . . . . . . . . . . . . 6 4. Digital Map Requirements . . . . . . . . . . . . . . . . . . 7 4.1. Core Requirements . . . . . . . . . . . . . . . . . . . . 7 4.2. Design Requirements . . . . . . . . . . . . . . . . . . . 8 4.3. Architectural Requirements . . . . . . . . . . . . . . . 9 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . 10 7.2. Informative References . . . . . . . . . . . . . . . . . 10 Appendix A. Related IETF Activities . . . . . . . . . . . . . . 13 A.1. Network Topology . . . . . . . . . . . . . . . . . . . . 13 A.2. Core Digital Map Components . . . . . . . . . . . . . . . 13 A.3. Additional Digital Map Components . . . . . . . . . . . . 14 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 14 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 1. Introduction Havel, et al. Expires 4 January 2025 [Page 2] Internet-Draft Digital Map Concept & Needs July 2024 1.1. Digital Twin Overview The network digital twin (referred to simply as Digital Twin) concepts and a reference architecture are discussed in the "Digital Twin Network: Concepts and Reference Architecture" [I-D.irtf-nmrg-network-digital-twin-arch]. That reference document defines the core elements of Digital Twin: Data, Models, Interfaces, and Mapping. The Digital Twin, constructed based on the four core technology elements, is intended to analyze, diagnose, emulate, and control the physical network in its whole lifecycle with the help of optimization algorithms, management methods, and expert knowledge. Also, that document [I-D.irtf-nmrg-network-digital-twin-arch] states that a Digital Twin can be seen as an indispensable part of the overall network system and provides a general architecture involving the whole lifecycle of physical networks in the future, serving the application of innovative network technologies (e.g., network planning, construction, maintenance and optimization, improving the automation and intelligence level of the network). 1.2. Digital Map Digital Map provides the core multi-layer topology model and data for the Digital Twin and connects them to the other Digital Twin models and data. This includes layers from physical topology to service topology. The Digital Map modelling defines the core topological entities (network, node, link, and interface) at each layer, their role in the network, core properties, and relationships both inside each layer and between the layers. The Digital Map model can be approached as a topological model that is linked to other functional parts of the Digital Twin and connects them all: configuration, maintenance, assurance (KPIs, status, health, and symptoms), Traffic-Engineering (TE), different behaviors and actions, simulation, emulation, mathematical abstractions, AI algorithms, etc. Havel, et al. Expires 4 January 2025 [Page 3] Internet-Draft Digital Map Concept & Needs July 2024 The Digital Map data consists of virtual instances of network and service topologies at different layers. The Digital Map provides the access to this data via standard APIs for both read and write operations (write operations for offline simulations), with query capabilities and links to other YANG modules (e.g., Service Assurance for Intent-based Networking (SAIN) [RFC9417], Service Attachement Points (SAPs) [RFC9408], Inventory [I-D.ietf-ivy-network-inventory-yang], and non-YANG models. 1.3. Digital Map as a Prerequisite for Digital Twin One of the important requirements for Digital Twin is to ease correlating all models and data to topological entities at different layers in the layered twin network. The Digital Map aims at providing a virtual instance of the topological information of the network, based on this Digital Map Model. *Building a Digital Map is prerequisite towards the Digital Twin.* The Digital Map model/data provide this missing correlation between the topology models/data and all other models/data: KPIs, alarms, incidents, inventory (with UUIDs), configuration, traffic engineering, planning, simulation ("what-if"), emulations, actions, and behaviors. Some of these models/data provide a device view, some provide a network or subnetwork view, while others focus more on the customer service perspective. All these views are needed for both inner and outer closed-loops. It is debatable what is part of the Digital Map itself versus what are pointers from the Digital Map to some other sources of information. As an example, a Digital Map should not specifically include all information about the device inventory (product name, vendor, product series, embedded software, and hardware/software versions, as specified in a Network Inventory. A pointer to another inventory system might be sufficient or support of means that ease the mapping between inventory and topology. Similarly, Digital Map should not specifically contain incidents, configuration, data plane monitoring, or even assurance information, simply to name a few, but should provide pointers to the different data sources. 1.4. Scope This document defines the concept of Digital Map, explains its connection to the Digital Twin, and identifies a set of Digital Map requirements and use cases. Havel, et al. Expires 4 January 2025 [Page 4] Internet-Draft Digital Map Concept & Needs July 2024 The document intends to be used as a reference for the assessment effort of the various topology modules to meet Digital Map requirements. 2. Terminology The document defines the following terms: Digital Twin: Virtual instance of a physical system (twin) that is continually updated with the latter's performance, maintenance and health status data throughout the physical system's life cycle (as defined in Section 2.2 of [I-D.irtf-nmrg-network-digital-twin-arch] Topology: Network topology defines how physical or logical nodes, links and interfaces are related and arranges. Service topology defines how service components (e.g., VPN instances, customer interfaces, and customer links) between customer sites are interrelated and arranged. There are at least 8 types of topologies: point to point, bus, ring, star, tree, mesh, hybrid and daisy chain. Topologies may be unidirectional or bidirectional (bus, some rings). Topology layer: Defines a layer in the multilayer topology. A multilayer topology models relationships between different layers of connectivity, where each layer represents a connectivity aspect of the network and service that needs to be configured, controlled and monitored. The topology layer can also represent what needs to be managed by a specific user, for example IGP layer can be of interest to the operator troubleshooting or optimizating the routing, while the optical layer may be of interest to the user managing the optical network. Some topology layers may relate closely to OSI layers, like L1 topology for physical topology, Layer 2 for link topology and Layer 3 for IPv4 and IPv6 topologies. Some topology layers represent the control aspects of Layer 3, like OSPF, IS-IS, or BGP. The service layer represents the service view of the connectivity, that can differ for different types of services and for different providers/solutions. The top layer represents the application / flow view of connectivity. Havel, et al. Expires 4 January 2025 [Page 5] Internet-Draft Digital Map Concept & Needs July 2024 Digital Map: Basis for the Digital Twin that provides a virtual instance of the topological information of the network. It provides the core multi-layer topology model and data for the Digital Twin and connects them to the other Digital Twin models and data. Digital Map modelling: The set of principles, guidelines, and conventions to model the Digital Map using the IETF [RFC8345] approach. They cover the network types (layers and sublayers), entity types, entity roles (network, node, termination point or link), entity properties and relationship types between entities. Digital Map model: Defines the core topological entities, their role in the network, core properties and relationships both inside each layer and between the layers. It is the basic topological model that is linked to other functional parts of the Digital Twin and connects them all: configuration, maintenance, assurance (KPIs, status, health, symptoms, etc.), traffic engineering, different behaviors, simulation, emulation, mathematical abstractions, AI algorithms, etc. Digital Map data: Consists of instances of network and service topologies at different layers. This includes instances of networks, nodes, links and termination points, topological relationships between nodes, links and termination points inside a network, relationships between instances belonging to different networks, links to functional data for the instances, including configuration, health, symptoms. :The data can be historical, real-time, or future data for 'what- if' scenarios. 3. Sample Digital Map Use Cases The following are sample Digital Twin use cases that require Digital Map: * Generic inventory queries * Service placement feasibility checks * Service-> subservice -> resource * Resource -> subservice -> service * Intent/service assurance Havel, et al. Expires 4 January 2025 [Page 6] Internet-Draft Digital Map Concept & Needs July 2024 * Service E2E and per-link KPIs on the Digital Map (delay, jitter, and loss) * Capacity planning * Network design * Simulation * Closed loop Overall, the Digital Map is needed to break down data islands and have a Digital Twin for emulation and closed loop, which is a catalyst for autonomous networking. 4. Digital Map Requirements 4.1. Core Requirements The following are the core requirements for the Digital Map (note that some of them are supported by default by [RFC8345]): REQ-BASIC-MODEL-SUPPORT: Basic model with network, node, link, and interface entity types. This means that users of the Digital Map model must be able to understand topology model at any layer via these core concepts only, without having to go to the details of the specific augmentations to understand the topology. REQ-LAYERED-MODEL: Layered Digital Map, from physical network (ideally optical, layer 2, layer 3) up to service and intent views. REQ-PROG-OPEN-MODEL: Open and programmable Digital Map. This includes "read" operations to retrieve the view of the network, typically as application-facing interface of Software Defined Networking (SDN) controllers or orchestrators. It also includes "write" operations, not for the ability to directly change the Digital Map data (e.g., changing the network or service parameters), but for offline simulations, also known as what-if scenarios. Running a "what-if" analysis requires the ability to take snapshots and to switch easily between them. Note that there is a need to distinguish between a change on the Havel, et al. Expires 4 January 2025 [Page 7] Internet-Draft Digital Map Concept & Needs July 2024 Digital Map for future simulation and a change that reflects the current reality of the network. REQ-STD-API-BASED: Standard based Digital Map Models and APIs, for multi-vendor support. Digital Map must provide the standard YANG APIs that provide for read/write and queries. These APIs must also provide the capability to retrieve the links to external data/models. REQ-COMMON-APP: Digital Map models and APIs must be common over different network domains (campus, core, data center, etc.). This means that clients of the Digital Map API must be able to understand the topology model of layers of any domain without having to understand the details of any technologies and domains. REQ-SEMANTIC: Digital Map must provide semantics for layered network topologies and for linking external models/data. REQ-LAYER-NAVIGATE: Digital Map must provide intra-layer and inter- layer relationships. REQ-EXTENSIBLE: Digital Map must be extensible with metadata. REQ-PLUGG: Digital Map must be pluggable. That is, * Must connect to other YANG modules for inventory, configuration, assurance, etc. * Given that no all involved components can be available using YANG, there is a need to connect Digital Map YANG model with other modelling mechanisms. REQ-GRAPH-TRAVERSAL: Digital Map must be optimized for graph traversal for paths. This means that only providing link nodes and source and sink relationships to termination-points may not be sufficient, we may need to have the direct relationship between the termination points or nodes. 4.2. Design Requirements The following are design requirements for modelling the Digital Map: REQ-TOPO-ONLY: Digital Map should contain only topological information. Digital Map is not required to contain all data required for all Havel, et al. Expires 4 January 2025 [Page 8] Internet-Draft Digital Map Concept & Needs July 2024 the management and use cases. However, it should be designed to support adequate pointers to other functional Digital Twin data and models to ease navigating in the overall system. For example: * ACLs and Route Policies are not required to be supported in the Digital Map, they would be linked to Digital Map * Dynamic paths may either be outside of the Digital Map or part of traffic engineering data/models REQ-PROPERTIES: Digital Map entities should mainly contain properties used to identify topological entities at different layers, identify their roles, and topological relationships between them. REQ-RELATIONSHIPS: Digital Map should contain only topological relationships inside each layer or between the layers (underlay/ overlay). REQ-CONDITIONAL: Provide capability for conditional retrieval of parts of Digital Map. REQ-TEMPO-HISTO: Must support geo-spatial, temporal, and historical data. The temporal and historical can be supported external to the Digital Map. 4.3. Architectural Requirements The following are the architectural requirements for the Digital Map: REQ-DM-SCALES: Scale, performance, ease of integration. REQ-DM-DISCOVERY: Initial discovery and dynamic (change only) synch with the physical network. 5. Security Considerations As this document covers the Digital Map concepts, requirements, and use cases, there is no specific security considerations. However, the RFC 8345 Security Considerations aspects will be useful when designing the solution. 6. IANA Considerations This document has no actions for IANA. 7. References Havel, et al. Expires 4 January 2025 [Page 9] Internet-Draft Digital Map Concept & Needs July 2024 7.1. Normative References [RFC8345] Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March 2018, . 7.2. Informative References [I-D.draft-ietf-nmop-network-incident-yang] Hu, T., Contreras, L. M., Wu, Q., Davis, N., and C. Feng, "A YANG Data Model for Network Incident Management", Work in Progress, Internet-Draft, draft-ietf-nmop-network- incident-yang-01, 28 June 2024, . [I-D.ietf-ccamp-network-inventory-yang] Yu, C., Belotti, S., Bouquier, J., Peruzzini, F., and P. Bedard, "A YANG Data Model for Network Hardware Inventory", Work in Progress, Internet-Draft, draft-ietf- ccamp-network-inventory-yang-02, 9 July 2023, . [I-D.ietf-ivy-network-inventory-yang] Yu, C., Belotti, S., Bouquier, J., Peruzzini, F., and P. Bedard, "A YANG Data Model for Network Inventory", Work in Progress, Internet-Draft, draft-ietf-ivy-network- inventory-yang-01, 4 March 2024, . [I-D.ietf-opsawg-ntw-attachment-circuit] Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S., and B. Wu, "A Network YANG Data Model for Attachment Circuits", Work in Progress, Internet-Draft, draft-ietf- opsawg-ntw-attachment-circuit-11, 15 May 2024, . [I-D.ietf-opsawg-teas-attachment-circuit] Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S., and B. Wu, "YANG Data Models for Bearers and 'Attachment Circuits'-as-a-Service (ACaaS)", Work in Progress, Internet-Draft, draft-ietf-opsawg-teas-attachment-circuit- 13, 29 May 2024, . Havel, et al. Expires 4 January 2025 [Page 10] Internet-Draft Digital Map Concept & Needs July 2024 [I-D.irtf-nmrg-network-digital-twin-arch] Zhou, C., Yang, H., Duan, X., Lopez, D., Pastor, A., Wu, Q., Boucadair, M., and C. Jacquenet, "Network Digital Twin: Concepts and Reference Architecture", Work in Progress, Internet-Draft, draft-irtf-nmrg-network-digital- twin-arch-05, 4 March 2024, . [I-D.ogondio-nmop-isis-topology] de Dios, O. G., Barguil, S., Lopez, V., Ceccarelli, D., and B. Claise, "A YANG Data Model for Intermediate System to intermediate System (IS-IS) Topology", Work in Progress, Internet-Draft, draft-ogondio-nmop-isis- topology-00, 4 March 2024, . [I-D.ogondio-opsawg-ospf-topology] de Dios, O. G., Barguil, S., and V. Lopez, "A YANG Data Model for Open Shortest Path First (OSPF) Topology", Work in Progress, Internet-Draft, draft-ogondio-opsawg-ospf- topology-01, 23 October 2023, . [I-D.wzwb-ivy-network-inventory-topology] Wu, B., Zhou, C., Wu, Q., and M. Boucadair, "A Network Inventory Topology Model", Work in Progress, Internet- Draft, draft-wzwb-ivy-network-inventory-topology-01, 29 April 2024, . [I-D.wzwb-opsawg-network-inventory-management] Wu, B., Zhou, C., Wu, Q., and M. Boucadair, "A YANG Network Data Model of Network Inventory", Work in Progress, Internet-Draft, draft-wzwb-opsawg-network- inventory-management-04, 19 October 2023, . [RFC8299] Wu, Q., Ed., Litkowski, S., Tomotaki, L., and K. Ogaki, "YANG Data Model for L3VPN Service Delivery", RFC 8299, DOI 10.17487/RFC8299, January 2018, . Havel, et al. Expires 4 January 2025 [Page 11] Internet-Draft Digital Map Concept & Needs July 2024 [RFC8466] Wen, B., Fioccola, G., Ed., Xie, C., and L. Jalil, "A YANG Data Model for Layer 2 Virtual Private Network (L2VPN) Service Delivery", RFC 8466, DOI 10.17487/RFC8466, October 2018, . [RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, August 2020, . [RFC8944] Dong, J., Wei, X., Wu, Q., Boucadair, M., and A. Liu, "A YANG Data Model for Layer 2 Network Topologies", RFC 8944, DOI 10.17487/RFC8944, November 2020, . [RFC9179] Hopps, C., "A YANG Grouping for Geographic Locations", RFC 9179, DOI 10.17487/RFC9179, February 2022, . [RFC9182] Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M., Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182, February 2022, . [RFC9291] Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil, S., and L. Munoz, "A YANG Network Data Model for Layer 2 VPNs", RFC 9291, DOI 10.17487/RFC9291, September 2022, . [RFC9408] Boucadair, M., Ed., Gonzalez de Dios, O., Barguil, S., Wu, Q., and V. Lopez, "A YANG Network Data Model for Service Attachment Points (SAPs)", RFC 9408, DOI 10.17487/RFC9408, June 2023, . [RFC9417] Claise, B., Quilbeuf, J., Lopez, D., Voyer, D., and T. Arumugam, "Service Assurance for Intent-Based Networking Architecture", RFC 9417, DOI 10.17487/RFC9417, July 2023, . [RFC9418] Claise, B., Quilbeuf, J., Lucente, P., Fasano, P., and T. Arumugam, "A YANG Data Model for Service Assurance", RFC 9418, DOI 10.17487/RFC9418, July 2023, . [RFC9522] Farrel, A., Ed., "Overview and Principles of Internet Traffic Engineering", RFC 9522, DOI 10.17487/RFC9522, January 2024, . Havel, et al. Expires 4 January 2025 [Page 12] Internet-Draft Digital Map Concept & Needs July 2024 Appendix A. Related IETF Activities A.1. Network Topology Interestingly, we could not find any network topology definition in IETF RFCs (not even in [RFC8345]) or Internet-Drafts. However, it is mentioned in multiple documents. As an example, in Overview and Principles of Internet Traffic Engineering [RFC9522], which mentions: | To conduct performance studies and to support planning of existing | and future networks, a routing analysis may be performed to | determine the paths the routing protocols will choose for various | traffic demands, and to ascertain the utilization of network | resources as traffic is routed through the network. Routing | analysis captures the selection of paths through the network, the | assignment of traffic across multiple feasible routes, and the | multiplexing of IP traffic over traffic trunks (if such constructs | exist) and over the underlying network infrastructure. A model of | network topology is necessary to perform routing analysis. A | network topology model may be extracted from: | | * Network architecture documents | | * Network designs | | * Information contained in router configuration files | | * Routing databases such as the link state database of an | interior gateway protocol (IGP) | | * Routing tables | | * Automated tools that discover and collate network topology | information. | | Topology information may also be derived from servers that monitor | network state, and from servers that perform provisioning | functions. A.2. Core Digital Map Components The following specifications are core for the Digital Map: * IETF network model and network topology model [RFC8345] * A YANG grouping for geographic location [RFC9179] * IETF modules that augment [RFC8345] for different technologies: Havel, et al. Expires 4 January 2025 [Page 13] Internet-Draft Digital Map Concept & Needs July 2024 - A YANG data model for Traffic Engineering (TE) Topologies [RFC8795] - A YANG data model for Layer 2 network topologies [RFC8944] - A YANG data model for OSFP topology [I-D.ogondio-opsawg-ospf-topology] - A YANG data model for IS-IS topology [I-D.ogondio-nmop-isis-topology] A.3. Additional Digital Map Components The Digital Map may need to link to the following models, some are already augmenting [RFC8345]: * Service Attachment Point (SAP) [RFC9408], augments 'ietf-network' data model [RFC8345] by adding the SAP. * SAIN [RFC9417] [RFC9418] * Network Inventory Model [I-D.ietf-ivy-network-inventory-yang] focuses on physical and virtual inventory. Logical inventory is currently outside of the scope. It does not augment RFC8345 like the two Internet-Drafts that it evolved from [I-D.ietf-ccamp-network-inventory-yang] and [I-D.wzwb-opsawg-network-inventory-management]. [I-D.wzwb-ivy-network-inventory-topology] correlates the network inventory with the general topology via RFC8345 augmentations that reference inventory. * KPIs: delay, jitter, loss * Attachment Circuits (ACs) [I-D.ietf-opsawg-ntw-attachment-circuit] and [I-D.ietf-opsawg-teas-attachment-circuit] * Configuration: L2SM [RFC8466], L3SM [RFC8299], L2NM [RFC9291], and L3NM [RFC9182] * Incident Management for Network Services [I-D.draft-ietf-nmop-network-incident-yang] Acknowledgments Many thanks to Mohamed Boucadair mohamed.boucadair@orange.com (mailto:mohamed.boucadair@orange.com) for his valuable contributions, reviews and comments. Havel, et al. Expires 4 January 2025 [Page 14] Internet-Draft Digital Map Concept & Needs July 2024 Many thanks to Nigel Davis ndavis@ciena.com (mailto:ndavis@ciena.com) for the valuable discussions and his confirmation of the modelling requirements. Contributors Ahmed Elhassany Swisscom Email: Ahmed.Elhassany@swisscom.com Authors' Addresses Olga Havel Huawei Email: olga.havel@huawei.com Benoit Claise Huawei Email: benoit.claise@huawei.com Oscar Gonzalez de Dios Telefonica Email: oscar.gonzalezdedios@telefonica.com Thomas Graf Swisscom Email: thomas.graf@swisscom.com Havel, et al. Expires 4 January 2025 [Page 15]