--- 1/draft-ietf-opsawg-model-automation-framework-00.txt 2020-02-26 05:13:25.216494888 -0800 +++ 2/draft-ietf-opsawg-model-automation-framework-01.txt 2020-02-26 05:13:25.300497020 -0800 @@ -1,143 +1,146 @@ Networking Working Group Q. Wu, Ed. Internet-Draft Huawei Intended status: Informational M. Boucadair, Ed. -Expires: May 20, 2020 Orange +Expires: August 29, 2020 Orange D. Lopez Telefonica I+D C. Xie China Telecom L. Geng China Mobile - November 17, 2019 + February 26, 2020 A Framework for Automating Service and Network Management with YANG - draft-ietf-opsawg-model-automation-framework-00 + draft-ietf-opsawg-model-automation-framework-01 Abstract Data models for service and network management provides a programmatic approach for representing (virtual) services or networks and deriving (1) configuration information that will be communicated to network and service components that are used to build and deliver the service and (2) state information that will be monitored and tracked. Indeed, data models can be used during various phases of the service and network management life cycle, such as service - instantiation, service provisioning, optimization, monitoring, and - diagnostic. Also, data models are instrumental in the automation of - network management. They also provide closed-loop control for the - sake of adaptive and deterministic service creation, delivery, and - maintenance. + instantiation, service provisioning, optimization, monitoring, + diagnostic, and assurance. Also, data models are instrumental in the + automation of network management. They also provide closed-loop + control for the sake of adaptive and deterministic service creation, + delivery, and maintenance. - This document provides a framework that describes and discusses an - architecture for service and network management automation that takes - advantage of YANG modeling technologies. This framework is drawn - from a network provider perspective irrespective of the origin of a - data module; it can accommodate even modules that are developed - outside the IETF. + This document describes an architecture for service and network + management automation that takes advantage of YANG modeling + technologies. This architecture is drawn from a network provider + perspective irrespective of the origin of a data module; it can thus + accommodate even modules that are developed outside the IETF. - The document aims to exemplify an approach that specifies the journey - from technology-agnostic services to technology-specific actions. + The document aims in particular to exemplify an approach that + specifies the journey from technology-agnostic services to + technology-specific actions. 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 May 20, 2020. + This Internet-Draft will expire on August 29, 2020. Copyright Notice - Copyright (c) 2019 IETF Trust and the persons identified as the + Copyright (c) 2020 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Architectural Concepts & Goals . . . . . . . . . . . . . . . 5 3.1. Data Models: Layering and Representation . . . . . . . . 5 - 3.2. Automation of Service Delivery Procedures . . . . . . . . 7 - 3.3. Service Fullfillment Automation . . . . . . . . . . . . . 8 - 3.4. YANG Modules Integration . . . . . . . . . . . . . . . . 8 - 4. Architecture Overview . . . . . . . . . . . . . . . . . . . . 9 - 4.1. Service Lifecycle Management Procedure . . . . . . . . . 10 + 3.2. Automation of Service Delivery Procedures . . . . . . . . 8 + 3.3. Service Fullfillment Automation . . . . . . . . . . . . . 9 + 3.4. YANG Modules Integration . . . . . . . . . . . . . . . . 9 + 4. Functional Bocks and Interactions . . . . . . . . . . . . . . 10 + 4.1. Service Lifecycle Management Procedure . . . . . . . . . 11 4.1.1. Service Exposure . . . . . . . . . . . . . . . . . . 11 - 4.1.2. Service Creation/Modification . . . . . . . . . . . . 11 - 4.1.3. Service Optimization . . . . . . . . . . . . . . . . 11 - 4.1.4. Service Diagnosis . . . . . . . . . . . . . . . . . . 12 - 4.1.5. Service Decommission . . . . . . . . . . . . . . . . 12 - 4.2. Service Fullfillment Management Procedure . . . . . . . . 12 - 4.2.1. Intended Configuration Provision . . . . . . . . . . 12 - 4.2.2. Configuration Validation . . . . . . . . . . . . . . 13 - 4.2.3. Performance Monitoring . . . . . . . . . . . . . . . 13 - 4.2.4. Fault Diagnostic . . . . . . . . . . . . . . . . . . 14 - 4.3. Multi-layer/Multi-domain Service Mapping . . . . . . . . 14 - 4.4. Service Decomposing . . . . . . . . . . . . . . . . . . . 14 + 4.1.2. Service Creation/Modification . . . . . . . . . . . . 12 + 4.1.3. Service Optimization . . . . . . . . . . . . . . . . 12 + 4.1.4. Service Diagnosis . . . . . . . . . . . . . . . . . . 13 + 4.1.5. Service Decommission . . . . . . . . . . . . . . . . 13 + 4.2. Service Fullfillment Management Procedure . . . . . . . . 13 + 4.2.1. Intended Configuration Provision . . . . . . . . . . 13 + 4.2.2. Configuration Validation . . . . . . . . . . . . . . 14 + 4.2.3. Performance Monitoring/Model-driven Telemetry . . . . 14 + 4.2.4. Fault Diagnostic . . . . . . . . . . . . . . . . . . 15 + 4.3. Multi-layer/Multi-domain Service Mapping . . . . . . . . 15 + 4.4. Service Decomposing . . . . . . . . . . . . . . . . . . . 15 - 5. YANG Data Model Integration Examples . . . . . . . . . . . . 14 - 5.1. L3VPN Service Delivery . . . . . . . . . . . . . . . . . 14 - 5.2. VN Lifecycle Management Example . . . . . . . . . . . . . 16 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 - 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17 - 10. Informative References . . . . . . . . . . . . . . . . . . . 18 - Appendix A. Layered YANG Modules Example Overview . . . . . . . 26 - A.1. Service Models: Definition and Samples . . . . . . . . . 26 - A.2. Network Models: Definitions and Samples . . . . . . . . . 27 - A.3. Device Models: Definitions and Samples . . . . . . . . . 30 - A.3.1. Model Composition . . . . . . . . . . . . . . . . . . 31 - A.3.2. Device Models: Definitions and Samples . . . . . . . 31 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 + 5. YANG Data Model Integration Examples . . . . . . . . . . . . 15 + 5.1. L3VPN Service Delivery . . . . . . . . . . . . . . . . . 15 + 5.2. VN Lifecycle Management . . . . . . . . . . . . . . . . . 17 + 5.3. Event-based Telemetry in the Device Self management . . . 18 + 6. Security Considerations . . . . . . . . . . . . . . . . . . . 19 + 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 + 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19 + 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 20 + 10.2. Informative References . . . . . . . . . . . . . . . . . 21 + Appendix A. Layered YANG Modules Example Overview . . . . . . . 29 + A.1. Service Models: Definition and Samples . . . . . . . . . 29 + A.2. Network Models: Definitions and Samples . . . . . . . . . 30 + A.3. Device Models: Definitions and Samples . . . . . . . . . 32 + A.3.1. Model Composition . . . . . . . . . . . . . . . . . . 33 + A.3.2. Device Models: Definitions and Samples . . . . . . . 34 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37 1. Introduction The service management system usually comprises service activation/ provision and service operation. Current service delivery procedures, from the processing of customer's requirements and order to service delivery and operation, typically assume the manipulation of data sequentially into multiple OSS/BSS applications that may be managed by different departments within the service provider's organization (e.g., billing factory, design factory, network operation center, etc.). In addition, many of these applications have been developed in-house over the years and operating in a silo mode: o The lack of standard data input/output (i.e., data model) also raises many challenges in system integration and often results in manual configuration tasks. - o Secondly, many current service fulfillment system might have limit - visibility to the network and therefore have slow response to the - network changes. + o Secondly, many current service fulfillment system might have a + limited visibility on the network state and therefore have slow + response to the network changes. Software Defined Networking (SDN) becomes crucial to address these challenges. SDN techniques [RFC7149] are meant to automate the overall service delivery procedures and typically rely upon (standard) data models that are used to not only reflect service providers'savoir-faire but also to dynamically instantiate and enforce a set of (service-inferred) policies that best accommodate what has been (contractually) defined (and possibly negotiated) with the customer. [RFC7149] provides a first tentative to rationalize that service provider's view on the SDN space by identifying concrete @@ -155,117 +158,172 @@ o Techniques used by service-requirement-derived dynamic resource allocation and policy enforcement schemes, so that networks can be programmed accordingly. o Dynamic feedback mechanisms that are meant to assess how efficiently a given policy (or a set thereof) is enforced from a service fulfillment and assurance perspective. Models are key for each of these technical items. Service and network management automation is an important step to improve the - agility of network operations and infrastructures. Models are also - important to ease integrating multi-vendor solutions. + agility of network operations. Models are also important to ease + integrating multi-vendor solutions. - YANG module developers have taken both top-down and bottom-up - approaches to develop modules [RFC8199], and also to establish a - mapping between network technology and customer requirements on the + YANG ([RFC7950]) module developers have taken both top-down and + bottom-up approaches to develop modules [RFC8199] and to establish a + mapping between a network technology and customer requirements on the top or abstracting common construct from various network technologies - on the bottom. At the time of writing this document (2019), there + on the bottom. At the time of writing this document (2020), there are many data models including configuration and service models that have been specified or are being specified by the IETF. They cover many of the networking protocols and techniques. However, how these models work together to configure a device, manage a set of devices involved in a service, or even provide a service is something that is not currently documented either within the IETF or other SDOs (e.g., MEF). - This document provides a framework that describes and discusses an - architecture for service and network management automation that takes - advantage of YANG modeling technologies and investigates how - different layer YANG data models interact with each other (e.g., - service mapping, model composing) in the context of service delivery - and fulfillment. + This document describes an architectural framework for service and + network management automation (Section 3) that takes advantage of + YANG modeling technologies and investigates how different layer YANG + data models interact with each other (e.g., service mapping, model + composing) in the context of service delivery and fulfillment + (Section 4). This framework is drawn from a network provider perspective irrespective of the origin of a data module; it can accommodate even modules that are developed outside the IETF. - The document also identifies a list of use cases to exemplify the - proposed approach, but it does not claim to be exhaustive. + The document identifies a list of use cases to exemplify the proposed + approach (Section 5), but it does not claim to be exhaustive. 2. Terminology The following terms are defined in [RFC8309][RFC8199] and are not redefined here: o Network Operator o Customer o Service o Data Model o Service Model o Network Element Module The document makes use of the following terms: - Network Model: The Network Model describes network level abstraction - or various aspects of a network infrastructure, including devices - and their subsystems, and relevant protocols operating at the link - and network layers across multiple devices. It can be used by a + Network Model: Describes a network level abstraction (or a subset of + aspects of a network infrastructure), including devices and their + subsystems, and relevant protocols operating at the link and + network layers across multiple devices. It can be used by a network operator to allocate the resource(e.g., tunnel resource, topology resource) for the service or schedule the resource to - meet the service requirements define in the Service Model. + meet the service requirements defined in a Service Model. - Device Model: Network Element YANG data module described in - [RFC8199]. + Device Model: Refers to the Network Element YANG data module + described in [RFC8199]. Device Model is also used to refer to + model a function embedded in a device (e.g., NAT [RFC8512], ACL + [RFC8519]). 3. Architectural Concepts & Goals 3.1. Data Models: Layering and Representation As described in [RFC8199], layering of modules allows for better reusability of lower-layer modules by higher-level modules while limiting duplication of features across layers. - The data modules developed by IETF can be classified into service - level, network level and device level modules. Different service - module at service level may rely on the same set of network level or - device level modules. + The data modules can be classified into Service, Network, and Device + Models. Different Service Models may rely on the same set of Network + and/or Device Models. - Service level modules usually follow top down approach and are mostly - customer-facing modules providing a common model construct for higher - level network services (e.g., L3VPN), which can be further mapped to - network technology-specific modules at lower layer (e.g., tunnel, + Service Models traditionally follow top down approach and are mostly + customer-facing YANG modules providing a common model construct for + higher level network services (e.g., L3VPN), which can be mapped to + network technology-specific modules at lower layers (e.g., tunnel, routing, QoS, security). For example, the service level can be used to characterise the network service(s) to be ensured between service nodes (ingress/egress) such as the communication scope (pipe, hose, funnel, ...), the directionality, the traffic performance guarantees (one-way delay (OWD), one-way loss, ...), etc. - Network level modules are mainly network resource-facing modules and + Figure 1 depicts the example of a VoIP service provider that relies + in the connectivity services offered by a network provider. These + connectivity services can be captured in a YANG Service Module that + reflects the service attributes that are shown in Figure 2. This + example follows the IP Connectivity Provisioning Profile template + defined in [RFC7297]. + + ,--,--,--. ,--,--,--. + ,-' SP1 `-. ,-' SP2 `-. + ( Service Site ) ( Service Site ) + `-. ,-' `-. ,-' + `--'--'--' `--'--'--' + x | o * * | + (2)x | o * * | + ,x-,--o-*-. (1) ,--,*-,--. + ,-' x o * * * * * * * * * `-. + ( x o +----( Internet ) + User---(x x x o o o o o o o o o o o o o o o o o o + `-. Provider ,-' `-. ,-' (3) + `--'--'--' `--'--'--' + + **** (1) Inter-SP connectivity + xxxx (2) Customer to SP connectivity + oooo (3) SP to any destination connectivity + + Figure 1: An Example of Service Connectivty Components + + Connectivity: Scope and Guarantees + * inter-SP connectivity (1) + - Pipe scope from the local to the remote VoIP gateway + - Full guarantees class + * Customer to SP connectivity (2) + - Hose/Funnel scope connecting the local VoIP gateway + to the customer access points + - Full guarantees class + * SP to any destination connectivity (3) + - Hose/Funnel scope from the local VoIP gateway to the + Internet gateway + - Delay guarantees class + Flow Identification + * Destination IP address (SBC, SBE, DBE) + * DSCP marking + Traffic Isolation + * VPN + Routing & Forwarding + * Routing rule to exclude ASes from the inter-domain paths + Notifications (including feedback) + * Statistics on aggregate traffic to adjust capacity + * Failures + * Planned maintenance operations + * Triggered by thresholds + + Figure 2: Sample Attributes Captured in a Service Model + + Network Models are mainly network resource-facing modules and describe various aspects of a network infrastructure, including devices and their subsystems, and relevant protocols operating at the link and network layers across multiple devices (e.g., Network topology and traffic- engineering Tunnel modules). - Device (and function) level modules usually follow a bottom-up - approach and are mostly technology-specific modules used to realize a - service (e.g., BGP, NAT). + Device (and function) Models usually follow a bottom-up approach and + are mostly technology-specific modules used to realize a service + (e.g., BGP, NAT). Each level maintains a view of the supported YANG modules provided by low-levels (see for example, Appendix A). - Figure 1 illustrates the overall layering model. + Figure 3 illustrates the overall layering model. +-----------------------------------------------------------------+ | +-----------------------+ | | | Orchestrator | Hierarchy Abstraction | | |+---------------------+| | | || Service Modeling || Service Model | | |+---------------------+| (Customer Oriented) | | | | Scope: "1:1" Pipe model | | | | Bidirectional | | |+---------------------+| +-+ BW:100M,OWD +-+ | @@ -285,177 +343,186 @@ | |+---------------------+| L3VPN over TE | | | | Instance Name/Access Interface| | +-----------------------+ Proto Type/BW/RD,RT,..mapping | | for hop | | | | | | +-----------------------+ | | | Device | Device Model | | |+--------------------+ | | | || Device Modeling | | Interface add,BGP Peer, | - | |+--------------------+ | Tunnel id,QoS/TE config | + | |+--------------------+ | Tunnel id, QoS/TE | | +-----------------------+ | +-----------------------------------------------------------------+ - Layering and representation + Figure 3: Layering and representation 3.2. Automation of Service Delivery Procedures - To dynamically offer and deliver service offerings, Service level - modules can be used by an operator. One or more monolithic Service - modules can be used in the context of a composite service activation - request (e.g., delivery of a caching infrastructure over a VPN). - Such modules are used to feed a decision-making intelligence to - adequately accommodate customer's needs. + Service Models can be used by an operator to expose its services to + its customers. Exposing such models allows to automate the + activation and the delivery of service orders. One or more + monolithic Service Models can be used in the context of a composite + service activation request (e.g., delivery of a caching + infrastructure over a VPN). Such modules are used to feed a + decision-making intelligence to adequately accommodate customer's + needs. - Also, such modules may be used jointly with services that require + Such modules may also be used jointly with services that require dynamic invocation. An example is provided by the service modules defined by the DOTS WG to dynamically trigger requests to handle DDoS attacks [I-D.ietf-dots-signal-channel][I-D.ietf-dots-data-channel]. - Network level modules can be derived from service level modules and - used to provision, monitor, instantiate the service, and provide - lifecycle management of network resources (e.g., expose network - resources to customers or operators to provide service fulfillment - and assurance and allow customers or operators to dynamically adjust - the network resources based on service requirements as described in - service level modules and the current network performance information - described in the telemetry modules). + Network Models can be derived from Service Models and used to + provision, monitor, instantiate the service, and provide lifecycle + management of network resources (e.g., expose network resources to + customers or operators to provide service fulfillment and assurance + and allow customers or operators to dynamically adjust the network + resources based on service requirements as described in Service + Models (e.g., Figure 2) and the current network performance + information described in the telemetry modules). 3.3. Service Fullfillment Automation - To operate the service, Device level modules derived from Service - level modules or Network level modules can be used to provision each - involved network function/device with the proper configuration - information, and operate the network based on service requirements as - described in the Service level module(s). + To operate a service, Device Models derived from Service Models or + Network Models can be used to provision each involved network + function/device with the proper configuration information, and + operate the network based on service requirements as described in the + Service Model(s) and local operational guidelines. In addition, the operational state including configuration that is in effect together with statistics should be exposed to upper layers to provide better network visibility (and assess to what extent the derived low level modules are consistent with the upper level - inputs). + inputs). Filters are enforced on the notifications that are + communicated to Service layers. The type of notifications may be + agreed in the Service Model. Note that it is important to correlate telemetry data with configuration data to be used for closed loops at the different stages of service delivery, from resource allocation to service operation, in particular. 3.4. YANG Modules Integration - To support top-down service delivery, YANG modules at different level - or at the same level need to be integrated together to enable - function, feature in the network device and get network setup. For - example, the service parameters captured in service level modules - need to be decomposed into a set of (configuration/notification) - parameters that may be specific to one or more technologies; these - technology-specific parameters are grouped together to define - technology-specific device level models or network level models. + To support top-down service delivery, YANG modules at different + levels or at the same level need to be integrated together for proper + service delivery (including, proper network setup). For example, the + service parameters captured in Service Models need to be decomposed + into a set of (configuration/notification) parameters that may be + specific to one or more technologies; these technology-specific + parameters are grouped together to define technology-specific device + level models or network level models. - In addition, these technology-specific device level models or network - level models can be further integrated with each other using schema - mount mechanism [RFC8528] to provision each involved network - function/device or each involved administrative domain to support - newly added module or features. A collection of device models - integrated together can be loaded and validated during implementation - time. + In addition, these technology-specific Device or Network Models can + be further integrated with each other using the schema mount + mechanism [RFC8528] to provision each involved network function/ + device or each involved administrative domain to support newly added + module or features. A collection of Device Models integrated + together can be loaded and validated during the implementation time. - Policies provide a higher layer of abstraction. Policy models can be - defined at service level, network level, or device level to provide - policy-based management and telemetry automation,e.g., telemetry data - can trigger a new policy that captures new network service - requirements. + High-level policies can be defined at Service or Network Models + (e.g., AS Exclude in the example depicted in Figure 2). Device + Models will be tweaked accordingly to provide policy-based + management. Policies can also be used for telemetry automation, + e.g., policies that contain conditions can trigger the generation and + pushing of new telemetry data. Performance measurement telemetry can be used to provide service - assurance at service level or at the network level. Performance - measurement telemetry model can tie with network level model or - service level model to monitor network performance or service level - agreement. + assurance at Service and/or Network levels. Performance measurement + telemetry model can tie with Service or Network Models to monitor + network performance or Service Level Agreement. -4. Architecture Overview +4. Functional Bocks and Interactions The architectural considerations described in Section 3 lead to the - architecture described in this section and illustrated in Figure 1. + architecture described in this section and illustrated in Figure 4. +------------------+ Service level | | ----------- V | - E2E E2E E2E + E2E E2E E2E E2E Service -- Service --------> Service --->Service ---+ Exposure Creation ^ Optimization | Diagnosis | /Modification | | | | |Diff | V Multi-layer | | E2E | E2E Multi-domain | | Service | Service Service Mapping| +------ Assurance ---+ Decommission | ^ |<-----------------+ | Network level | | +----+ ------------ V | | - Specific Specific | Specific - Service ----+---> Service ---+--+-> Service --+ - Creation ^ Optimization | | Diagnosis | - /Modification | | | V - | |Diff | | Specific - | | Specific----+ | Service - Service | | Service | Decommission - Decomposing | +------Assurance -----+ + Specific Specific | + Service ----+---> Service ---+--+ + Creation ^ Optimization | | + /Modification | | | + | |Diff | | + | | Specific----+ | + Service | | Service | + Decomposing | +------Assurance ----+ | ^ | | Aggregation Device level | +------------+ ------------ V | Service Intent Fullfillment Config ------> Config ----> Performance -->Fault Provision Validate Monitoring Diagnostic - Figure 1: Service and Network Lifecycle Management + Figure 4: Service and Network Lifecycle Management 4.1. Service Lifecycle Management Procedure Service lifecycle management includes end to end service lifecycle - management at the service level and specific network lifecycle - management at the network level. The end-to-end service lifecycle - management is multi-domain or multi-layer service management while - specific service lifecycle management is domain specific or layer - specific service lifecycle management. - - o Note: Clarify what is meant by "domain". + management at the service level and technology specific network + lifecycle management at the network level. The end-to-end service + lifecycle management is technology independent service management and + span across multiple administrative domain or multiple layers while + technology specific service lifecycle management is technology domain + specific or layer specific service lifecycle management. 4.1.1. Service Exposure A service in the context of this document (sometimes called a Network Service) is some form of connectivity between customer sites and the - Internet or between customer sites across the network operator's - network and across the Internet. + Internet or between customer sites across the operator's network and + across the Internet. Service exposure is used to capture services offered to customers (ordering and order handling). One typical example is that a customer can use a L3SM service model to request L3VPN service by providing the abstract technical characterization of the intended - service between cutsomer sites. + service between customer sites. Service model catalogs can be created along to expose the various services and the information needed to invoke/order a given service. 4.1.2. Service Creation/Modification A customer is (usually) unaware of the technology that the network operator has available to deliver the service, so the customer does not make requests specific to the underlying technology but is limited to making requests specific to the service that is to be delivered. This service request can be issued using the service model. - The service orchestrator/management system maps such service request - to its view. This view can be described as a network model and this - mapping may include a choice of which networks and technologies to - use depending on which service features have been requested. + Upon receiving the service request, the service orchestrator/ + management system should first verify whether the service + requirements in the service request can be met (i.e., whether there + is sufficient resource that can be allocated). + + In successful case, the service orchestrator/management system maps + such service request to its view. This view can be described as a + technology specific network model or a set of technology specific + device models and this mapping may include a choice of which networks + and technologies to use depending on which service features have been + requested. In addition, a customer may require to change underlying network infrastructure to adapt to new customer's needs and service requirements. This service modification can be issued in the same service model used by the service request. 4.1.3. Service Optimization Service optimization is a technique that gets the configuration of the network updated due to network change, incident mitigation, or @@ -482,32 +549,32 @@ o troubleshoot failures (i.e., fault verification and localization) o monitor service-level agreements and performance (i.e., performance management) When the network is down, service diagnosis should be in place to pinpoint the problem and provide recommendation (or instructions) for the network recovery. The service diagnosis information can be modelled as technology- - independent RPC operations for OAM protocols and technology- - independent abstraction of key OAM constructs for OAM protocols - [RFC8531][RFC8533]. These models can provide consistent + independent Remote Procedure Call (RPC) operations for OAM protocols + and technology-independent abstraction of key OAM constructs for OAM + protocols [RFC8531][RFC8533]. These models can provide consistent configuration, reporting, and presentation for the OAM mechanisms used to manage the network. 4.1.5. Service Decommission Service decommission allow the customer to stop the service and remove the service from active status and release the network resource that is allocated to the service. Customer can also use the - service model to withdraw the subscription to a service. + service model to withdraw the registration to a service. 4.2. Service Fullfillment Management Procedure 4.2.1. Intended Configuration Provision Intended configuration at the device level is derived from network model at the network level or service model at the service level and represents the configuration that the system attempts to apply. Take L3SM service model as an example, to deliver a L3VPN service, we need to map L3VPN service view defined in Service model into detailed @@ -525,209 +593,267 @@ listed in the document, as well as routing policies associated with those protocols. o Multicast Support o NAT or address sharing o Security function This specific configuration models can be used to configure PE and CE - devices within the site, e.g., A BGP policy model can be used to + devices within the site, e.g., a BGP policy model can be used to establish VPN membership between sites and VPN Service Topology. 4.2.2. Configuration Validation Configuration validation is used to validate intended configuration and ensure the configuration take effect. For example, a customer creates an interface "et-0/0/0" but the interface does not physically exist at this point, then configuration data appears in the status but does not appear in datastore. -4.2.3. Performance Monitoring +4.2.3. Performance Monitoring/Model-driven Telemetry When configuration is in effect in the device, datastore holds the complete operational state of the device - including learned, system, default configuraton and system state. + including learned, system, default configuration and system state. However the configurations and state of a particular device does not have the visibility to the whole network or information of the flow packets are going to take through the entire network. Therefore it becomes more difficult to operate the network without understanding the current status of the network. The management system should subscribe to updates of a YANG datastore in all the network devices for performance monitoring purpose and build full topological visibility to the network by aggregating and filtering these operational state from different sources. 4.2.4. Fault Diagnostic When configuration is in effect in the device, some device may be misconfigured(e.g.,device links are not consistent on both sides of the network connection), network resources be misallocated and services may be negatively affected without knowing what is going on in the network. - Technology-dependent nodes and remote procedure call (RPC) commands - are defined in technology-specific YANG data models which can use and - extend the base model described in Section 4.1.4can be used to deal - with these challenges. + Technology-dependent nodes and RPC commands are defined in + technology-specific YANG data models which can use and extend the + base model described in Section 4.1.4can be used to deal with these + challenges. - These RPC command recieved in the technology dependent node can be + These RPC commands received in the technology dependent node can be used to trigger technology specific OAM message exchange for fault verification and fault isolation,e.g., TRILL Multicast Tree Verification (MTV) RPC command [I-D.ietf-trill-yang-oam] can be used to trigger Multi-Destination Tree Verification Message defined in [RFC7455] to verify TRILL distribution tree integrity. 4.3. Multi-layer/Multi-domain Service Mapping Multi-layer/Multi-domain Service Mapping allow you map end to end abstract view of the service segmented at different layer or different administrative domain into domain specific view. One example is to map service parameters in L3VPN service model into configuration parameters such as RD, RT, and VRF in L3VPN network model. Another example is to map service parameters in L3VPN service model into TE tunnel parameter (e.g.,Tunnel ID) in TE model and VN - parameters (e.g., AP list, VN member) in TEAS VN model [I-D.ietf- - teas-actn-vn-yang]. + parameters (e.g., AP list, VN member) in TEAS VN model + [I-D.ietf-teas-actn-vn-yang]. 4.4. Service Decomposing Service Decomposing allows to decompose service model at the service level or network model at the network level into a set of device/ function models at the device level. These device models may be tied to specific device type or classified into a collection of related YANG modules based on service type and feature offered and load at the implementation time before configuration is loaded and validated. 5. YANG Data Model Integration Examples 5.1. L3VPN Service Delivery - L3SM | - Service | - Model | + L3SM | ^ + Service | | Notifications + Model | | +--------------------+----------------------------+ | +-----V- -------+ | | Orchestrator |Service Mapping| | | +-----+---------+ | | | | +--------------------+----------------------------+ - L3NM | - Network| - Model | + L3NM | ^ + Network| | L3NM Notifications + Model | | L3NM Capabilities +--------------------+----------------------------+ | Controller+--------V-----------+ | | | Service Decomposing| | | +-++------------++---+ | | || || | | || || | +-------------++---------- ++--------------------+ || || || || ||BGP,QoS || || || +----------+|NI,Intf,IP |+-----------------+ +--+--+ +++---+ --+---+ +--+--+ | CE1 |------| PE1 | | PE2 | ---------+ CE2 | +-----+ +-----+ +-----+ +-----+ - Figure 2: L3VPN Service Delivery Example + Figure 5: L3VPN Service Delivery Example - In reference to Figure 2, the following steps are performed to + In reference to Figure 5, the following steps are performed to deliver the L3VPN service within the network management automation architecture defined in this document: - 1. Customer Requests to create two sites based on L3SM Service model - with each having one network access connectivity: + 1. The Customer requests to create two sites (as per service + creation operation in Section 4.2.1) relying upon a L3SM Service + model with each having one network access connectivity: Site A: Network-Access A, Bandwidth=20M, for class "foo", guaranteed-bw-percent = 10, One-Way-Delay=70 msec Site B: Network-Access B, Bandwidth=30M, for class "foo1", guaranteed-bw-percent = 15, One-Way-Delay=60 msec 2. The Orchestrator extracts the service parameters from the L3SM - model. Then, it uses them as input to translate them into an - orchestrated configuration of network elements (e.g., RD, RT, - VRF, etc.) that is part of the L3NM network model. + model. Then, it uses them as input to translate ("service + mapping operation" in Section 4.4) them into an orchestrated + configuration of network elements (e.g., RD, RT, VRF) that are + part of the L3NM network model. 3. The Controller takes orchestrated configuration parameters in the L3NM network model and translates them into orchestrated - configuration of network elements that is part of BGP model, QoS - model, Network Instance model, IP management model, interface - model, etc. + ("service decomposing operation" in ) configuration of network + elements that are part of, e.g, BGP, QoS, Network Instance model, + IP management, and interface models. -5.2. VN Lifecycle Management Example + [I-D.ogondio-opsawg-uni-topology] is used for representing, managing + and controlling the User Network Interface (UNI) topology. + + L3NM inherits some of data elements from the L3SM. Likewise, the + L3NM expose some information to the above layer such as the + capabilities of an underlying network (which can be used to drive + service order handling) or notifications (to notify subscribers about + specific events or degradations as per agreed SLAs). + +5.2. VN Lifecycle Management | VN | Service | Model | - +------------------- --|--------------------------+ + +----------------------|--------------------------+ | Orchestrator | | - | +--------V--------+ +----------+ | - | | Service Mapping | +-+ECA Engine| | - | +-----------------+ | +--------^-+ | - +----------------------+----------+----------+----+ - TE | ECA | Telemetry - Tunnel | Policy| Model - Model | | | - +----------------------V----------V----------+----+ + | +--------V--------+ | + | | Service Mapping | | + | +-----------------+ | + +----------------------+--------------------^-----+ + TE | Telemetry + Tunnel | Model + Model | | + +----------------------V--------------------+----+ | Controller | | | +-------------------------------------------------+ +-----+ +-----+ +-----+ +-----+ | CE1 |------| PE1 | | PE2 |---------+ CE2 | +-----+ +-----+ +-----+ +-----+ - Figure 3 + Figure 6 - In reference to Figure 3, the following steps are performed to + In reference to Figure 6, the following steps are performed to deliver the VN service within the network management automation architecture defined in this document: - 1. Customer requests to create 'VN' based on Access point, - association between VN and Access point, VN member defined in the - VN YANG module. + 1. Customer requests (service exposure operation in Section 4.1.1) + to create 'VN' based on Access point, association between VN and + Access point, VN member defined in the VN YANG module. 2. The orchestrator creates the single abstract node topology based on the information captured in an VN YANG module. 3. The Customer exchanges connectivity-matrix on abstract node and explicit path using TE topology model with the orchestrator. This information can be used to instantiate VN and setup tunnels - between source and destination endpoints. + between source and destination endpoints (service creation + operation in Section 4.1.2). - 4. The telemetry which augments the TEAS VN model and corresponding - TE Tunnel model can be used to notify all the parameter changes + 4. The telemetry model which augments the TEAS VN model and + corresponding TE Tunnel model can be used to subscribe to + performance measurement data and notify all the parameter changes and network performance change related to VN topology or Tunnel - [I-D.ietf-teas-actn-pm-telemetry-autonomics]. This information - can be further used as input to ECA engine in the orchestrator - and generate ECA policy model to optimize the network. + [I-D.ietf-teas-actn-pm-telemetry-autonomics] and provide service + assurance (service optimization operation in Section 4.1.3). + +5.3. Event-based Telemetry in the Device Self management + + +----------------+ + | | + | Controller | + +----------------+ + | + | + ECA | + Model| ^ + | |Notif + | | + +------------V-------------+-------+ + |Device | Reconfig + | +-------+ +---------+ +--+---+ | + | | Event --> Event -->Event --> | + | | Source| |Condition| |Action| | + | +-------+ +---------+ +------+ | + +--------Update------trigger-------+ + + Figure 7: Event-based Telemetry + + In reference to Figure 7, the following steps are performed to + monitor state changes of managed objects or resource in the device + and provide device self management within the network management + automation architecture defined in this document: + + 1. To control which state a network device should be in or is + allowed to be in at any given time, a set of conditions and + actions are defined and correlated with network events (e.g., + allow the NETCONF server send updates only when the value exceeds + a certain threshold for the first time but not again until the + threshold is cleared.), which constitute an event-driven policy + or network control logic in the controller. + + 2. The controller pushes ECA policy to the network device and + delegate network control logic to the network device. + + 3. The network device generates ECA script from ECA model and + execute ECA script or network control logic based on Event. + Event based notification or telemetry can be triggered if a + certain condition is satisfied (model driven telemetry operation + in Section 4.2.3). 6. Security Considerations Security considerations specific to each of the technologies and protocols listed in the document are discussed in the specification documents of each of these techniques. (Potential) security considerations specific to this document are listed below: o Create forwarding loops by mis-configuring the underlying network. o Leak sensitive information: special care should be considered when translating between the various layers introduced in the document. - o ...tbc + o Some Service Models may include a traffic isolation clause, + appropriate technology-specific actions must be enforced to avoid + that traffic is accessible to non-authorized parties. 7. IANA Considerations There are no IANA requests or assignments included in this document. 8. Acknowledgements Thanks to Joe Clark, Greg Mirsky, and Shunsuke Homma for the review. 9. Contributors @@ -759,21 +885,29 @@ Weiqiang Cheng China Mobile Email: chengweiqiang@chinamobile.com Young Lee Sung Kyun Kwan University Email: younglee.tx@gmail.com -10. Informative References +10. References + +10.1. Normative References + + [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", + RFC 7950, DOI 10.17487/RFC7950, August 2016, + . + +10.2. Informative References [I-D.arkko-arch-virtualization] Arkko, J., Tantsura, J., Halpern, J., and B. Varga, "Considerations on Network Virtualization and Slicing", draft-arkko-arch-virtualization-01 (work in progress), March 2018. [I-D.asechoud-netmod-diffserv-model] Choudhary, A., Shah, S., Jethanandani, M., Liu, B., and N. Strahle, "YANG Model for Diffserv", draft-asechoud-netmod- @@ -782,21 +916,21 @@ [I-D.clacla-netmod-model-catalog] Clarke, J. and B. Claise, "YANG module for yangcatalog.org", draft-clacla-netmod-model-catalog-03 (work in progress), April 2018. [I-D.homma-slice-provision-models] Homma, S., Nishihara, H., Miyasaka, T., Galis, A., OV, V., Lopez, D., Contreras, L., Ordonez-Lucena, J., Martinez- Julia, P., Qiang, L., Rokui, R., Ciavaglia, L., and X. Foy, "Network Slice Provision Models", draft-homma-slice- - provision-models-01 (work in progress), July 2019. + provision-models-02 (work in progress), November 2019. [I-D.ietf-bess-evpn-yang] Brissette, P., Shah, H., Hussain, I., Tiruveedhula, K., and J. Rabadan, "Yang Data Model for EVPN", draft-ietf- bess-evpn-yang-07 (work in progress), March 2019. [I-D.ietf-bess-l2vpn-yang] Shah, H., Brissette, P., Chen, I., Hussain, I., Wen, B., and K. Tiruveedhula, "YANG Data Model for MPLS-based L2VPN", draft-ietf-bess-l2vpn-yang-10 (work in progress), @@ -818,24 +952,24 @@ Vallin, S. and M. Bjorklund, "YANG Alarm Module", draft- ietf-ccamp-alarm-module-09 (work in progress), April 2019. [I-D.ietf-ccamp-flexigrid-media-channel-yang] Madrid, U., Perdices, D., Lopezalvarez, V., Dios, O., King, D., Lee, Y., and G. Galimberti, "YANG data model for Flexi-Grid media-channels", draft-ietf-ccamp-flexigrid- media-channel-yang-02 (work in progress), March 2019. [I-D.ietf-ccamp-flexigrid-yang] - Madrid, U., Perdices, D., Lopezalvarez, V., King, D., and - Y. Lee, "YANG data model for Flexi-Grid Optical Networks", - draft-ietf-ccamp-flexigrid-yang-04 (work in progress), - July 2019. + Madrid, U., Perdices, D., Lopezalvarez, V., King, D., Lee, + Y., and H. Zheng, "YANG data model for Flexi-Grid Optical + Networks", draft-ietf-ccamp-flexigrid-yang-05 (work in + progress), January 2020. [I-D.ietf-ccamp-l1csm-yang] Lee, Y., Lee, K., Zheng, H., Dhody, D., Dios, O., and D. Ceccarelli, "A YANG Data Model for L1 Connectivity Service Model (L1CSM)", draft-ietf-ccamp-l1csm-yang-10 (work in progress), September 2019. [I-D.ietf-ccamp-mw-yang] Ahlberg, J., Ye, M., Li, X., Spreafico, D., and M. Vaupotic, "A YANG Data Model for Microwave Radio Link", @@ -853,58 +987,58 @@ Xu, "OTN Tunnel YANG Model", draft-ietf-ccamp-otn-tunnel- model-09 (work in progress), November 2019. [I-D.ietf-ccamp-wson-tunnel-model] Lee, Y., Zheng, H., Guo, A., Lopezalvarez, V., King, D., Yoon, B., and R. Vilata, "A Yang Data Model for WSON Tunnel", draft-ietf-ccamp-wson-tunnel-model-04 (work in progress), September 2019. [I-D.ietf-dots-data-channel] - Boucadair, M. and R. K, "Distributed Denial-of-Service - Open Threat Signaling (DOTS) Data Channel Specification", - draft-ietf-dots-data-channel-31 (work in progress), July - 2019. + Boucadair, M. and T. Reddy.K, "Distributed Denial-of- + Service Open Threat Signaling (DOTS) Data Channel + Specification", draft-ietf-dots-data-channel-31 (work in + progress), July 2019. [I-D.ietf-dots-signal-channel] - K, R., Boucadair, M., Patil, P., Mortensen, A., and N. - Teague, "Distributed Denial-of-Service Open Threat + Reddy.K, T., Boucadair, M., Patil, P., Mortensen, A., and + N. Teague, "Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Specification", draft- - ietf-dots-signal-channel-38 (work in progress), October - 2019. + ietf-dots-signal-channel-41 (work in progress), January + 2020. [I-D.ietf-idr-bgp-model] Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP YANG Model for Service Provider Networks", draft-ietf-idr- bgp-model-07 (work in progress), October 2019. [I-D.ietf-ippm-stamp-yang] Mirsky, G., Xiao, M., and W. Luo, "Simple Two-way Active Measurement Protocol (STAMP) Data Model", draft-ietf-ippm- stamp-yang-05 (work in progress), October 2019. [I-D.ietf-ippm-twamp-yang] Civil, R., Morton, A., Rahman, R., Jethanandani, M., and K. Pentikousis, "Two-Way Active Measurement Protocol (TWAMP) Data Model", draft-ietf-ippm-twamp-yang-13 (work in progress), July 2018. [I-D.ietf-mpls-base-yang] Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A YANG Data Model for MPLS Base", draft-ietf-mpls-base- - yang-11 (work in progress), September 2019. + yang-12 (work in progress), February 2020. [I-D.ietf-pim-igmp-mld-snooping-yang] Zhao, H., Liu, X., Liu, Y., Sivakumar, M., and A. Peter, "A Yang Data Model for IGMP and MLD Snooping", draft-ietf- - pim-igmp-mld-snooping-yang-08 (work in progress), June - 2019. + pim-igmp-mld-snooping-yang-09 (work in progress), January + 2020. [I-D.ietf-pim-igmp-mld-yang] Liu, X., Guo, F., Sivakumar, M., McAllister, P., and A. Peter, "A YANG Data Model for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD)", draft-ietf-pim-igmp-mld-yang-15 (work in progress), June 2019. [I-D.ietf-pim-yang] Liu, X., McAllister, P., Peter, A., Sivakumar, M., Liu, @@ -913,101 +1047,115 @@ progress), May 2018. [I-D.ietf-rtgwg-device-model] Lindem, A., Berger, L., Bogdanovic, D., and C. Hopps, "Network Device YANG Logical Organization", draft-ietf- rtgwg-device-model-02 (work in progress), March 2017. [I-D.ietf-rtgwg-policy-model] Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data Model for Routing Policy Management", draft-ietf-rtgwg- - policy-model-07 (work in progress), September 2019. + policy-model-08 (work in progress), January 2020. [I-D.ietf-softwire-iftunnel] Boucadair, M., Farrer, I., and R. Asati, "Tunnel Interface Types YANG Module", draft-ietf-softwire-iftunnel-07 (work in progress), June 2019. [I-D.ietf-softwire-yang] Farrer, I. and M. Boucadair, "YANG Modules for IPv4-in- IPv6 Address plus Port (A+P) Softwires", draft-ietf- softwire-yang-16 (work in progress), January 2019. [I-D.ietf-spring-sr-yang] Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J. Tantsura, "YANG Data Model for Segment Routing", draft- - ietf-spring-sr-yang-13 (work in progress), July 2019. + ietf-spring-sr-yang-15 (work in progress), January 2020. [I-D.ietf-supa-generic-policy-data-model] Halpern, J. and J. Strassner, "Generic Policy Data Model for Simplified Use of Policy Abstractions (SUPA)", draft- ietf-supa-generic-policy-data-model-04 (work in progress), June 2017. + [I-D.ietf-teas-actn-pm-telemetry-autonomics] + Lee, Y., Dhody, D., Karunanithi, S., Vilata, R., King, D., + and D. Ceccarelli, "YANG models for VN/TE Performance + Monitoring Telemetry and Scaling Intent Autonomics", + draft-ietf-teas-actn-pm-telemetry-autonomics-01 (work in + progress), October 2019. + [I-D.ietf-teas-actn-vn-yang] Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B. Yoon, "A Yang Data Model for VN Operation", draft-ietf- teas-actn-vn-yang-07 (work in progress), October 2019. [I-D.ietf-teas-sf-aware-topo-model] Bryskin, I., Liu, X., Lee, Y., Guichard, J., Contreras, L., Ceccarelli, D., and J. Tantsura, "SF Aware TE Topology - YANG Model", draft-ietf-teas-sf-aware-topo-model-03 (work - in progress), March 2019. + YANG Model", draft-ietf-teas-sf-aware-topo-model-04 (work + in progress), November 2019. [I-D.ietf-teas-te-service-mapping-yang] Lee, Y., Dhody, D., Fioccola, G., WU, Q., Ceccarelli, D., and J. Tantsura, "Traffic Engineering (TE) and Service Mapping Yang Model", draft-ietf-teas-te-service-mapping- yang-02 (work in progress), September 2019. [I-D.ietf-teas-yang-l3-te-topo] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Dios, "YANG Data Model for Layer 3 TE Topologies", draft-ietf-teas-yang-l3-te-topo-05 (work in progress), July 2019. [I-D.ietf-teas-yang-path-computation] - Busi, I. and S. Belotti, "Yang model for requesting Path - Computation", draft-ietf-teas-yang-path-computation-06 - (work in progress), July 2019. + Busi, I., Belotti, S., Lopezalvarez, V., Sharma, A., and + Y. Shi, "Yang model for requesting Path Computation", + draft-ietf-teas-yang-path-computation-08 (work in + progress), December 2019. [I-D.ietf-teas-yang-rsvp-te] Beeram, V., Saad, T., Gandhi, R., Liu, X., Bryskin, I., and H. Shah, "A YANG Data Model for RSVP-TE Protocol", draft-ietf-teas-yang-rsvp-te-07 (work in progress), July 2019. [I-D.ietf-teas-yang-sr-te-topo] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and S. Litkowski, "YANG Data Model for SR and SR TE - Topologies", draft-ietf-teas-yang-sr-te-topo-05 (work in - progress), July 2019. + Topologies", draft-ietf-teas-yang-sr-te-topo-06 (work in + progress), November 2019. [I-D.ietf-teas-yang-te] Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin, "A YANG Data Model for Traffic Engineering Tunnels and Interfaces", draft-ietf-teas-yang-te-22 (work in progress), November 2019. [I-D.ietf-teas-yang-te-topo] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", draft-ietf-teas-yang-te-topo-22 (work in progress), June 2019. [I-D.ietf-trill-yang-oam] Kumar, D., Senevirathne, T., Finn, N., Salam, S., Xia, L., and H. Weiguo, "YANG Data Model for TRILL Operations, Administration, and Maintenance (OAM)", draft-ietf-trill- yang-oam-05 (work in progress), March 2017. + [I-D.ogondio-opsawg-uni-topology] + Dios, O., Barguil, S., WU, Q., and M. Boucadair, "A YANG + Model for User-Network Interface (UNI) Topologies", draft- + ogondio-opsawg-uni-topology-00 (work in progress), + November 2019. + [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 2006, . [RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer 2 Virtual Private Networks (L2VPNs)", RFC 4664, DOI 10.17487/RFC4664, September 2006, . [RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private @@ -1171,21 +1319,21 @@ o L2SM model [RFC8466] defines the L2VPN service ordered by a customer from a network operator. o VN model [I-D.ietf-teas-actn-vn-yang]provides a YANG data model generally applicable to any mode of Virtual Network (VN) operation. A.2. Network Models: Definitions and Samples - Figure 4 depicts a set of Network models such as topology models or + Figure 8 depicts a set of Network models such as topology models or tunnel models: | | Topo YANG modules | Tunnel YANG modules | ------------------------------------------------| +------------+ | | |Network Top | | +------+ +-----------+ | | Model | | |Other | | TE Tunnel | | +----+-------+ | |Tunnel| +------+----+ | | +--------+ | +------+ | | @@ -1194,21 +1342,21 @@ | +--------+ | |MPLS-TE | |RSVP-TE | |SR TE | |---+L2 Topo | | | Tunnel | | Tunnel | |Tunnel | | +--------+ | +--------+ +--------+ +-------+ | +--------+ | |---+TE Topo | | | +--------+ | | +--------+ | +---+L3 Topo | | +--------+ | - Figure 4: Sample Resource Facing Network Models + Figure 8: Sample Resource Facing Network Models Topology YANG module Examples: o Network Topology Models: [RFC8345] defines a base model for network topology and inventories. Network topology data include link resource, node resource, and terminate-point resources. o TE Topology Models: [I.D-ietf-teas-yang-te-topo] defines a data model for representing and manipulating TE topologies. @@ -1293,21 +1441,21 @@ modules developed elsewhere. Policy rules within an operator's environment can be used to express high-level, possibly network- wide, policies to a network management function (within a controller, an orchestrator, or a network element). The network management function can then control the configuration and/or monitoring of network elements and services. This document describes the SUPA basic framework, its elements, and interfaces. A.3. Device Models: Definitions and Samples - Network Element models (Figure 5) are used to describe how a service + Network Element models (Figure 9) are used to describe how a service can be implemented by activating and tweaking a set of functions (enabled in one or multiple devices, or hosted in cloud infrastructures) that are involved in the service delivery. The following figure uses IETF defined models as an example. +----------------+ --|Device Model | | +----------------+ | +------------------+ +---------------+ | |Logical Network | @@ -1338,21 +1486,21 @@ | +-------+ --|VRRP | | +-------+ --|SR/SRv6| | +-------+ --|ISIS-SR| | +-------+ --|OSPF-SR| +-------+ - Figure 5: Network Element Modules Overview + Figure 9: Network Element Modules Overview A.3.1. Model Composition o Device Model [I.D-ietf-rtgwg-device-model] presents an approach for organizing YANG modules in a comprehensive logical structure that may be used to configure and operate network devices. The structure is itself represented as an example YANG module, with all of the related component models logically organized in a way that is