Networking Working Group Q. Wu Internet-Draft Huawei Intended status: Informational M. Boucadair Expires: December 21, 2019 Orange Y. Lee Futurewei June 19, 2019 A Framework for Automating Service and Network Management with YANG draft-wu-model-driven-management-virtualization-04 Abstract Model-driven service and network management provides a programmatic and standard-based approach for representing (virtual) services or networks and configuration to the network device that are used to build and deliver the service. Models can be used at various phases of service and network management life cycle such as service instantiation, service provisionning, optimization, monitoring, and diagnostic. Also, models can be designed to automate network management and 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 with YANG modeling technologies. An applicability of YANG data models to automation of virtualized network service is also investigated. The document aims to exemplify an approach to illustrate 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 December 21, 2019. Wu, et al. Expires December 21, 2019 [Page 1] Internet-Draft Service and Network Management Automation June 2019 Copyright Notice Copyright (c) 2019 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. IETF YANG Modules: An Overview . . . . . . . . . . . . . . . 4 2.1. Network Service and Resource Models . . . . . . . . . . . 5 2.1.1. Network Service Models: Definition and Samples . . . 6 2.1.2. Network Resource Models . . . . . . . . . . . . . . . 7 2.2. Network Element Models . . . . . . . . . . . . . . . . . 10 2.2.1. Model Composition . . . . . . . . . . . . . . . . . . 11 2.2.2. Protocol/Function Configuration Models . . . . . . . 12 3. Architectural Concepts . . . . . . . . . . . . . . . . . . . 15 3.1. Data Models: Layering and Representation . . . . . . . . 15 3.2. Service Activation, Provision, and Invocation Automation 15 3.3. Service Enforcement Automation . . . . . . . . . . . . . 16 3.4. Modules Decomposition and Composition . . . . . . . . . . 16 4. Architecture Overview . . . . . . . . . . . . . . . . . . . . 17 4.1. End-to-End Service Delivery and Service Assurance Procedure . . . . . . . . . . . . . . . . . . . . . . . . 17 4.1.1. Resource Collection and Abstraction (a) . . . . . . . 17 4.1.2. Service Exposure & Abstraction (b) . . . . . . . . . 18 4.1.3. IP Service Mapping (c) . . . . . . . . . . . . . . . 19 4.1.4. IP Service Composition (d) . . . . . . . . . . . . . 20 4.1.5. IP Service Provision (e) . . . . . . . . . . . . . . 20 4.1.6. Performance Measurement and Alarm Telemetry (f) . . . 20 4.1.7. IP Service to TE Mapping (g) . . . . . . . . . . . . 20 4.1.8. Path Management (h) . . . . . . . . . . . . . . . . . 21 4.1.9. TE Resource Exposure (i) . . . . . . . . . . . . . . 21 5. Sample Service Coordination via YANG Moodules . . . . . . . . 22 5.1. L3VPN Service Delivery via Coordinated YANG Modules . . . 22 5.2. 5G Transport Service Delivery via Coordinated YANG Modules . . . . . . . . . . . . . . . . . . . . . . . . . 22 6. Modules Usage in Automated Virtualized Network Environment: Sample Examples . . . . . . . . . . . . . . . . . . . . . . . 24 Wu, et al. Expires December 21, 2019 [Page 2] Internet-Draft Service and Network Management Automation June 2019 6.1. Network-initiated Resource Creation . . . . . . . . . . . 24 6.2. Customer-initiated Dynamic Resource Creation . . . . . . 26 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 29 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 29 11. Informative References . . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37 1. Introduction The service management system usually comprises service activation/ provision and service enforcement. Traditional service delivery work flow process, from customer order to the actual service provision, typically involves input data sequentially into multiple OSS/BSS applications managed by different departments. Many of these applications are custom built over the years and operating in a silo mode. The lack of standard data input/output also causes many challenges in system integration and results in manual data entry. Secondly, traditional service fulfillment lack a programmatic and standards-based way of writing configurations to any network device and has slow response to the network changes and doesn't provide real time monitoring capability in high frequency and in high throughput on the current state of networking. Therefore, model-driven network management becomes crucial to address these challenges. For years, the IETF has been driving the industry transition from an overloaded Software Defined Networking (SDN) buzzword to focus on specific areas such as modeling-driven network management. [RFC7149] provides a first tentative to rationalize that space by identifying concrete technical domains that need to be considered and for which solutions can be provided: o Techniques for the dynamic discovery of topology, devices, and capabilities, along with relevant information and data models that are meant to precisely document such topology, devices, and their capabilities. o Techniques for exposing network services [RFC8309] and their characteristics. 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. Wu, et al. Expires December 21, 2019 [Page 3] Internet-Draft Service and Network Management Automation June 2019 Models are key for each of these technical items. Automation is an important step to improve the agility of network operations and infrastructure. In the later development, as described in [RFC8199], YANG module developers have taken both top-down and bottom-up approaches to develop modules and establish mapping between network technology and customer requirements on the top or abstracting common construct from various network technologies. At the time of writing this document (2019), we see the large number of data models including configuration models and service models developed or under development in IETF covering much of networking protocols and techniques. In addition, how these models work together to fully configure a device, manage a set of devices involved in a service, or even provide a service aren't developed yet in IETF. This document takes both bottom up approach and top down approach to provide an architectural framework for network management automation, with a focus on network virtualization environment. This document also describes specific YANG modules needed to realize connectivity services and investigates how top down built model (e.g., customer-facing data models) interact with bottom up built model (network resource-facing data models) in the context of service delivery and assurance. The document identifies a comprehensive list of modules to exemplify the proposed approach, but the document does not claim to be exhaustive. It is not the intent of this document to provide an inventory of tools and mechanisms used in specific network and service management domains; such inventory can be found in documents such as [RFC7276]. 2. IETF YANG Modules: An Overview Figure 1 provides an overview of various macro-functional blocks to which belong the various IETF-defined modules. Wu, et al. Expires December 21, 2019 [Page 4] Internet-Draft Service and Network Management Automation June 2019 <> +-----------------------------------------------------------------------+ | << Network Service Models>> | | +----------------+ +----------------+ +-------------+ +-------------+ | | | L3SM | | L2SM | | TEAS VN | | L1CSM | | | | Service Model | | Service Model | |Service Model| |Service Model| | | +----------------+ +----------------+ +-------------+ +-------------+ | |------------------------------------------------------------------- | | << Network Resource Models >> | | +------------+ +-------+ +----------------+ +------------+ | | |Network Topo| | Tunnel| |Path Computation| |FM/PM/Alarm | | | | Models | | Models| | API Models | | OAM Models| | | +------------+ +-------+ +----------------+ +------------+ | +-----------------------------------------------------------------------+ -------------------------------------------------------------------- > +-----------------------------------------------------------------------+ | <> | | +-------------+ +---------------+ +----------------+ | | |Device Model | |Logical Network| |Network Instance| | | | | |Element Model | | Model | | | +-------------+ +---------------+ +----------------+ | |---------------------------------------------------------------------- | | << Component Models>> | |+---------++---------++---------++----------++---------++---------+ | || || || ||Common || || OAM: | | || Routing ||Transport|| Policy ||(interface||Multicast|| | | ||(e.g.,BGP||(e.g., ||(e.g, ACL||multicast || (IGMP ||FM,PM, | | || OSPF) || MPLS) || QoS) || IP, ... )|| MLD,...)||Alarm | ...| |+---------++---------++---------++----------++---------++---------+ | +-----------------------------------------------------------------------+ Figure 1: An overview of IETF YANG Modules 2.1. Network Service and Resource Models Service and Network Resource modules define what the "service"/"resource" is. These modules can be classified into two categories: 1. Network Service Models (Section 2.1.1) 2. Network Resource Models (Section 2.1.2) Wu, et al. Expires December 21, 2019 [Page 5] Internet-Draft Service and Network Management Automation June 2019 2.1.1. Network Service Models: Definition and Samples As described in [RFC8309], the service is some form of connectivity between customer sites and the Internet and/or between customer sites across the network operator's network and across the Internet. More concretely, an IP connectivity service can be defined as the IP transfer capability characterized by a (Source Nets, Destination Nets, Guarantees, Scope) tuple where "Source Nets" is a group of unicast IP addresses, "Destination Nets" is a group of IP unicast and/or multicast addresses, and "Guarantees" reflects the guarantees (expressed in terms of Quality Of Service (QoS), performance, and availability, for example) to properly forward traffic to the said "Destination" [RFC7297]. For example, o L3SM model [RFC8299] defines the L3VPN service ordered by a customer from a network operator. o L2SM model [RFC8466] defines the L2VPN service ordered by a customer from a network operator. o L1CSM model [I-D.ietf-ccamp-l1csm-yang] defines a YANG module for Layer 1 Connectivity Service Model (L1CSM). o TEAS VN model [I-D.ietf-teas-actn-vn-yang] defines a YANG module for the Abstraction and Control of Traffic Engineered (TE) networks (ACTN) Virtual Network Service (VNS) operation. Unlike L3SM model, ACTN model can also be used as operator-facing model, e.g., establish interconnections between L3VPN sites across multiple ASes. o [I-D.ietf-teas-te-service-mapping-yang] defines a YANG module to map service model (e.g., L3SM) and Traffic Engineering model (e.g., TE Tunnel or the ACTN model). This model is applicable to the operation's need for a control and management of VPN services with TE tunnel support and principally used to allow monitoring and diagnostic of the management systems to assess how the service requests are mapped onto underlying network resources and TE models. o Composed VPN model [I-D.evenwu-opsawg-yang-composed-vpn] defines a YANG module that can be used by a network operator to configure a VPN service in multiple administrative domain environment consisting of L2VPN or L3VPN or a mixture of the two. This model provides an abstracted view of VPN service configuration components at different layer. Wu, et al. Expires December 21, 2019 [Page 6] Internet-Draft Service and Network Management Automation June 2019 2.1.2. Network Resource Models Figure 2 depicts a set of Network resource YANG modules such as topology models or tunnel models: | | Topo YANG modules | Tunnel YANG modules |Resource NM Tool ------------------------------------------------|-- ------------ +------------+ | | |Network Top | | +------+ +-----------+ | +-------+ | Model | | |Other | | TE Tunnel | | | LIME | +----+-------+ | |Tunnel| +------+----+ | | Model | | +--------+ | +------+ | | |/PM/FM | |---+Svc Topo| | +--------+-+--------+ |Model | | +--------+ | +----+---+ +---+----+ +-+-----+ +-------+ | +--------+ | |MPLS-TE | |RSVP-TE | |SR TE | +--------+ |---+L2 Topo | | | Tunnel | | Tunnel | |Tunnel | | Alarm | | +--------+ | +--------+ +--------+ +-------+ | Model | | +--------+ | +--------+ |---+TE Topo | | +-----------+ | +--------+ | |Path | | +--------+ | |Computation| +---+L3 Topo | |API Model | +----|---+ +-----------+ +---------+---------+ | | | +---|---+ +--|---+ +---|-+ |SR Topo| |SR TE | |L3 TE| | Model | | Topo | |Topo | +-------+ +------+ +-----+ Figure 2: Sample Resource Facing Network Models Topology YANG modules: 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. This module is extended from network topology model defined in [RFC8345] with TE topologies specifics. This model contains technology agnostic TE Topology building blocks that can be augmented and used by other technology-specific TE Topology models. Wu, et al. Expires December 21, 2019 [Page 7] Internet-Draft Service and Network Management Automation June 2019 o L3 Topology Models [RFC8346] defines a data model for representing and manipulating L3 Topologies. This model is extended from the network topology model defined in [RFC8345] with L3 topologies specifics. o L2 Topology Models [I.D-ietf-i2rs-yang-l2-topology] defines a data model for representing and manipulating L2 Topologies. This model is extended from the network topology model defined in [RFC8345] with L2 topologies specifics. o L3 TE Topology Models When traffic engineering is enabled on a layer 3 network topology, there will be a corresponding TE topology. [I.D-ietf-teas-yang- l3-te-topo] defines data models for layer 3 traffic engineering topologies. Two data models are defined, one is layer 3 TE topology model, the other is packet switching TE topology model. Layer 3 TE topology model is extended from Layer 3 topology model. Packet switching TE topology model is extended from TE topology model. o SR TE Topology Models [I-D.ietf-teas-yang-sr-te-topo] defines a YANG module for Segment Routing (SR) topology and Segment Routing (SR) traffic engineering (TE) topology. Two models are defined, one is SR topology model, the other is SR TE topology model, SR topology model is extended from L3 Topology model. SR TE topology model is extended from both SR Topology model and L3 TE topology model. o SF Aware TE Topology YANG module [I-D. ietf-teas-sf-aware-topo-model] defines a YANG module for TE network topologies that are network service and function aware. o Optical Transport Topology Models: * OTN Transport Topology Model: [I-D.ietf-ccamp-otn-topo-yang] defines a YANG module to describe the topologies of an Optical Transport Network (OTN). * WSON Transport Topology Model: [I-D.ietf-ccamp-wson-yang] defines a YANG module for the routing and wavelength assignment (RWA) Traffic Engineering (TE) topology in wavelength switched optical networks (WSONs). Wu, et al. Expires December 21, 2019 [Page 8] Internet-Draft Service and Network Management Automation June 2019 * Flex-Grid Transport Topology Model: [I-D.ietf-ccamp-flexigrid- yang] defines a YANG module for flexi-grid objects in the dynamic optical network, including the nodes, transponders and links between them, as well as how such links interconnect nodes and transponders. Tunnel YANG modules: o Tunnel identities [I-D.ietf-softwire-iftunnel] to ease manipulating extensions to specific tunnels. o TE Tunnel Model [I.D-ietf-teas-yang-te] defines a YANG module for the configuration and management of TE interfaces, tunnels and LSPs. o SR TE Tunnel Model [I.D-ietf-teas-yang-te] augments the TE generic and MPLS-TE model(s) and defines a YANG module for Segment Routing (SR) TE specific data. o MPLS TE Model [I.D-ietf-teas-yang-te] augments the TE generic and MPLS-TE model(s) and defines a YANG module for MPLS TE configurations, state, RPC and notifications. o RSVP-TE MPLS Model [I.D-ietf-teas-yang-rsvp-te] augments the RSVP-TE generic module with parameters to configure and manage signaling of MPLS RSVP-TE LSPs. o Optical Transport Tunnel Models: * Flexigrid Media Channel Tunnel Models: [I-D.ccamp-flexigrid- media-channel-yang] defines a YANG module for the flexi-grid media-channel. This YANG module defines the whole path from a source transponder or node to the destination through a number of intermediate nodes in the flexi-grid network. * WSON Tunnel Model: [I-D.ccamp-wson-tunnel-model] defines a YANG module for WSON tunnel model. * OTN Tunnel Model: [I-D. ietf-ccamp-otn-tunnel-model]defines a YANG module for OTN tunnel Model. Wu, et al. Expires December 21, 2019 [Page 9] Internet-Draft Service and Network Management Automation June 2019 Resource NM Tool Models: o Path Computation API Model [I.D-ietf-teas-path-computation] YANG module for a stateless RPC which complements the stateful solution defined in [I.D-ietf-teas- yang-te]. o OAM Models (including Fault Management (FM) and Performance Monitoring) [RFC8532] defines a base YANG module for the management of OAM protocols that use Connectionless Communications. [RFC8533] defines a retrieval method YANG module for connectionless OAM protocols. [RFC8531] defines a base YANG module for connection oriented OAM protocols. These three models are intended to provide consistent reporting, configuration and representation for connection-less OAM and Connection oriented OAM separately. Alarm monitoring is a fundamental part of monitoring the network. Raw alarms from devices do not always tell the status of the network services or necessarily point to the root cause. [I.D- ietf-ccamp-alarm-module]defines a YANG module for alarm management. o Generic Policy Model The Simplified Use of Policy Abstractions (SUPA) policy-based management framework [RFC8328] defines base YANG modules to encode policy. These models point to device-, technology-, and service- specific YANG 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. 2.2. Network Element Models Network Element models (Figure 3) are used to describe how a service can be implemented by activating and tweaking a set of functions (enabled in one or multiple devices) that are involved in the service delivery. Wu, et al. Expires December 21, 2019 [Page 10] Internet-Draft Service and Network Management Automation June 2019 +----------------+ --|Device Model | | +----------------+ | +------------------+ +---------------+ | |Logical Network | | | --| Element Mode | | Architecture | | +------------------+ | | | +----------------------+ +-------+-------+ --|Network Instance Mode | | | +----------------------+ | | +-------------------+ | --|Routing Type Model | | +-------------------+ +-------+----------+----+------+------------+-----------+-------+ | | | | | | | +-+-+ +---+---+ +--+------+ +-+-+ +-----+---+ +---+-+ | |ACL| |Routing| |Transport| |OAM| |Multicast| | PM | Others +---+ |-------+ +---------+ +---+ +---------+ +-----+ | +-------+ +----------+ +-------+ +-----+ +-----+ --|Core | |MPLS Basic| |BFD | |IGMP | |TWAMP| | |Routing| +----------+ +-------+ |/MLD | +-----+ | +-------+ |MPLS LDP | |LSP Ping +-----+ |OWAMP| --|BGP | +----------+ +-------+ |PIM | +-----+ | +-------+ |MPLS Static |MPLS-TP| +-----+ |LMAP | --|ISIS | +----------+ +-------+ |MVPN | +-----+ | +-------+ +-----+ --|OSPF | | +-------+ --|RIP | | +-------+ --|VRRP | | +-------+ --|SR/SRv6| | +-------+ --|ISIS-SR| | +-------+ --|OSPF-SR| +-------+ Figure 3: Network Element Modules 2.2.1. 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 Wu, et al. Expires December 21, 2019 [Page 11] Internet-Draft Service and Network Management Automation June 2019 represented as an example YANG module, with all of the related component models logically organized in a way that is operationally intuitive, but this model is not expected to be implemented. o Logical Network Element Model [RFC8530] defines a logical network element module which can be used to manage the logical resource partitioning that may be present on a network device. Examples of common industry terms for logical resource partitioning are Logical Systems or Logical Routers. o Network Instance Model [RFC8529] defines a network instance module. This module can be used to manage the virtual resource partitioning that may be present on a network device. Examples of common industry terms for virtual resource partitioning are Virtual Routing and Forwarding (VRF) instances and Virtual Switch Instances (VSIs). 2.2.1.1. Schema Mount Modularity and extensibility were among the leading design principles of the YANG data modeling language. As a result, the same YANG module can be combined with various sets of other modules and thus form a data model that is tailored to meet the requirements of a specific use case. [RFC8528] defines a mechanism, denoted schema mount, that allows for mounting one data model consisting of any number of YANG modules at a specified location of another (parent) schema. That capability does not cover design time. 2.2.2. Protocol/Function Configuration Models BGP: [I-D.ietf-idr-bgp-yang-model] defines a YANG module for configuring and managing BGP, including protocol, policy, and operational aspects based on data center, carrier and content provider operational requirements. MPLS: [I-D.ietf-mpls-base-yang] defines a base model for MPLS which serves as a base framework for configuring and managing an MPLS switching subsystem. It is expected that other MPLS technology YANG modules (e.g. MPLS LSP Static, LDP or RSVP-TE models) will augment the MPLS base YANG module. Wu, et al. Expires December 21, 2019 [Page 12] Internet-Draft Service and Network Management Automation June 2019 QoS: [I-D.asechoud-netmod-diffserv-model] describes a YANG module of Differentiated Services for configuration and operations. ACL: Access Control List (ACL) is one of the basic elements used to configure device forwarding behavior. It is used in many networking technologies such as Policy Based Routing, Firewalls, etc. [RFC8519] describes a data model of Access Control List (ACL) basic building blocks. NAT: For the sake of network automation and the need for programming Network Address Translation (NAT) function in particular, a data model for configuring and managing the NAT is essential. [RFC8512] defines a YANG module for the NAT function covering a variety of NAT flavors such as Network Address Translation from IPv4 to IPv4 (NAT44), Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers (NAT64), customer-side translator (CLAT), Stateless IP/ICMP Translation (SIIT), Explicit Address Mappings (EAM) for SIIT, IPv6-to-IPv6 Network Prefix Translation (NPTv6), and Destination NAT. [RFC8513] specifies a YANG module for the DS-Lite AFTR. Stateless Address Sharing: [I-D.ietf-softwire-yang] specifies a YANG module for A+P address sharing, including Lightweight 4over6, Mapping of Address and Port with Encapsulation (MAP-E), and Mapping of Address and Port using Translation (MAP-T) softwire mechanisms. Multicast: [I-D.ietf-pim-yang] defines a YANG module that can be used to configure and manage Protocol Independent Multicast (PIM) devices. [I-D.ietf-pim-igmp-mld-yang] defines a YANG module that can be used to configure and manage Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) devices. [I-D.ietf-pim-igmp-mld- snooping-yang] defines a YANG module that can be used to configure and manage Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping devices. EVPN: [I-D.ietf-bess-evpn-yang] defines a YANG module for Ethernet VPN services. The model is agnostic of the underlay. It apply to MPLS as well as to VxLAN encapsulation. The model is also agnostic of the services including E-LAN, E-LINE and E-TREE services. This document mainly focuses on EVPN and Ethernet-Segment instance framework. Wu, et al. Expires December 21, 2019 [Page 13] Internet-Draft Service and Network Management Automation June 2019 L3VPN: [I-D.ietf-bess-l3vpn-yang] defines a YANG module that can be used to configure and manage BGP L3VPNs [RFC4364]. It contains VRF specific parameters as well as BGP specific parameters applicable for L3VPNs. L2VPN: [I-D.ietf-bess-l2vpn-yang] defines a YANG module for MPLS based Layer 2 VPN services (L2VPN) [RFC4664] and includes switching between the local attachment circuits. The L2VPN model covers point-to-point VPWS and Multipoint VPLS services. These services use signaling of Pseudowires across MPLS networks using LDP [RFC8077][RFC4762] or BGP [RFC4761]. Routing Policy: [I-D.ietf-rtgwg-policy-model] defines a YANG module for configuring and managing routing policies in a vendor- neutral way and based on actual operational practice. The model provides a generic policy framework which can be augmented with protocol-specific policy configuration. BFD: [I-D.ietf-bfd-yang]defines a YANG module that can be used to configure and manage Bidirectional Forwarding Detection (BFD) [RFC5880]. BFD is a network protocol which is used for liveness detection of arbitrary paths between systems. SR/SRv6: [I-D.ietf-spring-sr-yang] a YANG module for segment routing configuration and operation. [I-D.raza-spring- srv6-yang] defines a YANG module for Segment Routing IPv6 (SRv6) base. The model serves as a base framework for configuring and managing an SRv6 subsystem and expected to be augmented by other SRv6 technology models accordingly. Core Routing: [RFC8349] defines the core routing data model, which is intended as a basis for future data model development covering more-sophisticated routing systems. It is expected that other Routing technology YANG modules (e.g., VRRP, RIP, ISIS, OSPF models) will augment the Core Routing base YANG module. PM: [I.D-ietf-ippm-twamp-yang] defines a data model for client and server implementations of the Two-Way Active Measurement Protocol (TWAMP). [I.D-ietf-ippm-stamp-yang] defines the data model for implementations of Session-Sender and Session-Reflector for Simple Two-way Active Measurement Protocol (STAMP) mode using YANG. Wu, et al. Expires December 21, 2019 [Page 14] Internet-Draft Service and Network Management Automation June 2019 [RFC8194] defines a data model for Large-Scale Measurement Platforms (LMAPs). 3. Architectural Concepts 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 IETF has developed a number of service level, network level and device level modules. Different service level modules may rely on the same set of network level or device level modules. Service level modules usually follow top down approach and are mostly customer- facing models providing a common model construct for higher level network services, which can be further mapped to network technology- specific models at lower layer. Network level modules mostly follow bottom up approach and are mainly network resource-facing model 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 TE Tunnel modules). Device level modules usually follow bottom up approach and are mostly technology-specific modules used to realize a service. 3.2. Service Activation, Provision, and Invocation Automation To provide more adaptive (a.k.a., agile) service offerings, Service level modules can be used by an operator to structure how it communicates with the customer. One or more monolithic Service modules can be used in teh context of a composite service activation requets (e.g., deliver of a caching infrastructure over a VPN). Such modules are used to feed a decision-making intelligence to rapidly accommodate customer' needs. Also, such modules may be used jointly with services that require dynamic service invocation. A typical example is 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 module can be translated from service level module and used to provision, monitor, instantiate the service and provide life cycle management of network resource,e.g., expose network resource to the customer or operators to provide service assurance on network Wu, et al. Expires December 21, 2019 [Page 15] Internet-Draft Service and Network Management Automation June 2019 service and allow customer or operator to re-optimize the network based on service requirements described in the service level model. 3.3. Service Enforcement Automation To provide network management automation, Device level modules translated from Service level modules or Network level modules can be used to provision each involved network function/device and operate the network based on service requirements described in the Service level module(s). In addition, the operational state including configuration that is in effect and status together with statistics should be exposed to upper layers to provide better network visibility (and assess to what extent the translated low level modules are honoring the upper level inputs). Note that it is important is to stitch telemetry data with configuration data to provide closed loop life cycle management on the network as a system (including device-centric views). 3.4. Modules Decomposition and Composition To support top-down service delivery, the service parameters captured in service level module(s) need to be decomposed into a set of configuration parameters specific to one or more technologies; these technology-specific parameters will be grouped together per technology to define technology-specific device level model or network level model. In addition, these technology-specific device level models can be further assembled together to provision each involved network function/device or each involved administrative domain to improve provision efficiency. For example, IETF rtgwg and netmod working groups have already been tasked to define model composition mechanism (i.e., Schema Mount mechanism) and relevant grouping base models such as network instance model, logical network element model. The model composition mechanism can be used to assembler different model together while grouping based models can be used to setup and administrate both virtualized system and physical system. IETF also developed YANG catalog tool to manage metadata around IETF- defined modules; it allows both YANG developers and operators to discover appropriate YANG modules that may be used to automate services operations. This YANG catalog tools can be used to select appropriate models for grouping purposes or even to identify gaps. Wu, et al. Expires December 21, 2019 [Page 16] Internet-Draft Service and Network Management Automation June 2019 4. Architecture Overview The architectural considerations and conclusions described in the previous section lead to the architecture described in this section and illustrated in Figure 4. The interfaces and interactions shown in the figure and labeled (a) through (j) are further described in Section 4.1. +-----------------+ ---------------- |Service Requester| Service Level| +-----------------+ | +-------------|--------------------------------------------------+ | | +--------V---------+ +------------+ | | | | Service Exposure |----------------- IP Service | | | | +-------(b)--------+ | Mapping | | | | | +--(c)-|-----+ | | | | | ---------------- | |---------->|<----------------+ | Network Level| | | +--------V---------+ | | | | | | | IP Service to TE | +------->|<-----------+ | | | | | Mapping | | | | | | | | | +-------(f)--------+ | | +------|-----+ | | | | | | +-----|-----+| | IP Service | +---+--+| | | | +--------V---------+ |TE Resource|| | Composition| |Alarm/|| | | | | TE Path | | Exposure || +--(d)-|-----+ | PM || | | | | Management +----(h)----+| | +-(g) -+| | | | +-------(e)--------+ | | +------|------+ | | | | | | | | IP Service | | | | | | +-----------------+ | | Provision +-----| | | | | | +-(e)--|------+ | | | | +-----------++ | | | | | Resource | | | | | | Collection | | | | |------------------------+&Abstraction| | | | +----(a)-----+ ---------------- +----------------------------------------------------------------+ Figure 4: Service and Network Management Automation with YANG 4.1. End-to-End Service Delivery and Service Assurance Procedure 4.1.1. Resource Collection and Abstraction (a) Network Resource such as links, nodes, or terminate-point resources can be collected from the network and aggregated or abstracted to the management system. Periodic fetching of data is not an adequate solution for applications requiring frequent or prompt updates of Wu, et al. Expires December 21, 2019 [Page 17] Internet-Draft Service and Network Management Automation June 2019 network resource. Applying polling-based solutions to retrieve network resource also imposes a load on networks, devices, and applications. These limitations can be addressed by including generic object subscription mechanisms within network elements. These resources can be modelled using network topology model, L3 topology model, L2 topology model, TE topology model, L3 TE topology model, SR TE topology models at different layers. In some cases, there may have multiple overlay topologies built on top of the same underlay topology, and the underlay topology can be also built from one or more lower layer underlay topology. In some cases, there may have multiple overlay topologies built on top of the same underlay topology, and the underlay topology can be also built from one or more lower layer underlay topology. The network resources and management objects in these multi-layer topologies are not recommended to be exposed to customers who (will) order the service from the management system, instead it will be exposed to the management system for IP service mapping and TE path Management. The abstract view is likely to be technology-agnostic. 4.1.2. Service Exposure & Abstraction (b) Service exposure & abstraction is used to capture services offered to customers. Service abstraction can be used by a customer to request a service (ordering and order handling). One typical example is that a customer can use L3SM service model to request L3VPN service by providing the abstract technical characterization of the intended service. Such L3VPN service describes various aspects of network infrastructure, including devices and their subsystems, and relevant protocols operating at the link and network layers across multiple device. The L3SM service model can be used to interact with the network infrastructure, e.g., configure sites, decide QoS parameters to be applied to end to end connectivity between VPN sites, select PEs, CEs, etc. Service catalogs can be created to expose the various services and the information needed to invoke/order a given service. YANG modules can be grouped into various service bundles; each service bundle is corresponding to a set of YANG modules that have been released or published. Then, a mapping can be established Wu, et al. Expires December 21, 2019 [Page 18] Internet-Draft Service and Network Management Automation June 2019 between service abstraction at higher layer and service bundle or a set of YANG modules at lower layer. 4.1.3. IP Service Mapping (c) Service abstraction starts with high-level abstractions exposing the business capabilities or capturing customer requirements. Then, it needs to maps them to resource abstraction and specific network technologies. Therefore, the interaction between service abstraction in the overlay and network resource abstraction in the underlay is required. For example, in the L3SM service model, we describe VPN service topology including sites relationship, e.g., hub and spoke and any to any, single homed, dual-homed, multi-homed relation between PEs and CEs, but we don't know how this service topology can be mapped into underlying network topology. For detailed interaction, please refer to Section 4.1.8 In addition, there is a need to decide on a mapping between service abstraction and underlying specific network technologies. Take L3SM service model as an example, to realize L3VPN service, we need to map L3SM service view defined in Service model into detailed configuration view defined by specific configuration models for network elements, these configuration models include: o VRF definition, including VPN Policy expression o Physical Interface o IP layer (IPv4, IPv6). o QoS features such as classification, profiles, etc. o Routing protocols: support of configuration of all protocols listed in the document, as well as routing policies associated with those protocols. o Multicast Support o NAT or address sharing o Security functions Wu, et al. Expires December 21, 2019 [Page 19] Internet-Draft Service and Network Management Automation June 2019 4.1.4. IP Service Composition (d) These detailed configuration models are further assembled together into service bundle described inFigure 3 using, e.g., device model, logical network element model or network instance model defined in [I.D-ietf-rtgwg-device-model] [RFC8530] [RFC8529] and provide the association between an interface and its associated LNE and NI and populate them into appropriate devices(e.g., PE and CE). 4.1.5. IP Service Provision (e) IP Service Provision is used to provision network infrastructure using various configuration models, e.g., use network element models such as BGP, ACL, QoS, Interface model, Network instance models to configure PE and CE device within the site. BGP Policy model is used to establish VPN membership between sites and VPN Service Topology. Traditionally, "push" service element configuration model one by one to the network device and provide association between an interface and each service element configuration model is not efficient. To automate configuration of the service elements, we first assemble all related network elements models into logical network element model defined in [RFC8530] and then establish association with an interface and a set of network element configurations. In addition, IP Service Provision can be used to setup tunnels between sites and setup tunnels between PE and CE within the site when tunnels related configuration parameters can be generated from service abstraction. However when tunnels related configuration parameters can not be generated from service abstraction, IP Service to TE Mapping procedure is required. 4.1.6. Performance Measurement and Alarm Telemetry (f) Once the tunnel is setup, PM and Warning information per tunnel or per link based on network topology can be collected and report to the management system. This information can be used to optimize the network or provide troubleshooting support. 4.1.7. IP Service to TE Mapping (g) Take L3VPN service model as an example, the management system will use L3SM service model to determine where to connect each site- network-access of a particular site to the provider network (e.g., PE, aggregation switch). L3SM Service model proposes parameters and constraints that can influence the meshing of the site-network- access. Wu, et al. Expires December 21, 2019 [Page 20] Internet-Draft Service and Network Management Automation June 2019 Nodes used to connect a site may be captured in relevant clauses of a service exposure model (e.g., Customer Nodes Map [RFC7297]). When Site location is determined, PE and CE device location will be selected. Then we can replace parameters and constraints that can influence the meshing of the site-network-access with specified PE and CE device information associated with site-network-access and generate resource facing VN Overlay Resource model. One example of resource facing VN Overlay Resource model is TEAS VN Service Model [I-D.ietf-teas-actn-vn-yang]. This VN Overlay Resource model can be used to calculate node and link resource to Meet service requirements based on Network Topology models collected at step (a). 4.1.8. Path Management (h) Path Management includes Path computation and Path setup. For example, we can translate L3SM service model into resource facing VN Model, with selected PE and CE in each site, we can calculate point to point or multipoint end to end path between sites based on VN Overlay Resource Model. After identifying node and link resources required to meet service requirements, the mapping between overlay topology and underlay topology can be established, e.g., establish an association between VPN service topology defined in customer facing model and underlying network topology defined in the TE topology model (e.g., one overlay node is supported by multiple underlay nodes, one overlay link is supported by multiple underlay nodes) and generate end to end VN topology. 4.1.9. TE Resource Exposure (i) When tunnels related configuration parameters can not be generated from service abstraction, IP Service to TE Mapping procedure can be used to generate TE Resource Exposure view, this TE resource Exposure view can be modeled as resource facing VN model which is translated and instantiated from L3SM model and manage TE resource based on path management information and PM and alarm telemetry information. Operators may use this dedicated TE resource Exposure view to dynamically capture the overall network status and topology to: o Perform all the requested recovery operations upon detecting network failures affecting the network service. Wu, et al. Expires December 21, 2019 [Page 21] Internet-Draft Service and Network Management Automation June 2019 o Adjust resource distribution and update to end to end Service topology models o Provide resource scheduling to better guarantee services for customers and to improve the efficiency of network resource usage. 5. Sample Service Coordination via YANG Moodules 5.1. L3VPN Service Delivery via Coordinated YANG Modules Take L3VPN service as an example, IETF has already developed L3VPN service model [RFC8299] which can be used to describe L3VPN service. To enforce L3VPN service and program the network, a set of network element models are needed, e.g., BGP model, Network Instance model, ACL model, Multicast Model, QoS model, or NAT model. These network element models can be grouped into different release bundles or feature bundle using Schema Mount technology to meet different tailored requirements and realize L3VPN service. To support the creation of logical network elements on a network device and enable automation of virtualized network, Logical Network Element (LNE) model can be used to manage its own set of modules such as ACL, QoS, or Network Instance modules. 5.2. 5G Transport Service Delivery via Coordinated YANG Modules The overview of network slice structure as defined in the 3GPP 5GS is shown in Figure 5. The terms are described in specific 3GPP documents (e.g., [TS.23.501-3GPP] and [TS.28.530-3GPP]). Wu, et al. Expires December 21, 2019 [Page 22] Internet-Draft Service and Network Management Automation June 2019 <================== E2E-NSI =======================> : : : : : : : : : : <====== RAN-NSSI ======><=TRN-NSSI=><====== CN-NSSI ======>VL[APL] : : : : : : : : : : : : : : : : : : RW[NFs ]<=TRN-NSSI=>[NFs ]<=TRN-NSSI=>[NFs ]<=TRN-NSSI=>[NFs ]VL[APL] . . . . . . . . . . . . .. . . . . . . . . . . . . .. .,----. ,----. ,----.. ,----. .,----. ,----. ,----.. UE--|RAN |---| TN |---|RAN |---| TN |---|CN |---| TN |---|CN |--[APL] .|NFs | `----' |NFs |. `----' .|NFs | `----' |NFs |. .`----' `----'. .`----' `----'. . . . . . . . . . . . . .. . . . . . . . . . . . . .. RW RAN MBH CN DN *Legends UE: User Equipment RAN: Radio Access Network CN: Core Network DN: Data Network TN: Transport Network MBH: Mobile Backhaul RW: Radio Wave NF: Network Function APL: Application Server NSI: Network Slice Instance NSSI: Network Slice Subnet Instance Figure 5: Overview of Structure of NS in 3GPP 5GS To support 5G service (e.g., 5G MBB service), L3VPN service model [RFC8299] and TEAS VN model [I-D. ietf-teas-actn-vn-yang] can be both provided to describe 5G MBB Transport Service or connectivity service. L3VPN service model is used to describe end-to-end connectivity service while TEAS VN model is used to describe TE connectivity service between VPN sites or between RAN NFs and Core network NFs. VN in TEAS VN model and support point-to-point or multipoint-to- multipoint connectivity service and can be seen as one example of network slice. TE Service mapping model can be used to map L3VPN service requests onto underlying network resource and TE models to get TE network setup. Wu, et al. Expires December 21, 2019 [Page 23] Internet-Draft Service and Network Management Automation June 2019 For IP VPN service provision, L3VPN service model is translated into a set of network element configuration parameters, these configuration parameters will be bound to different network element models and group them together to form feature bundle or service bundle to get L3VPN network setup. 6. Modules Usage in Automated Virtualized Network Environment: Sample Examples 6.1. Network-initiated Resource Creation Wu, et al. Expires December 21, 2019 [Page 24] Internet-Draft Service and Network Management Automation June 2019 |(2) | V +-------------------+ | Management System | (3)(4)(5) +-------------------+ +--------------------------------------------------------+ / _[CE2] _[CE3] / / _/ : \_ _/ : \_ / / _/ : \_ _/ : \_ / / _/ : \_ _/ : \_ / / / : \ / : \ / /[CE1]_________________[PE1] [PE2]_________________[CE4] / +---------:--------------:------------:--------------:---+ "Service" -------------------------------------------------------------------- +---------------------+ +---------------------+"Resource" / [Y5]... / / [Z5]______[Z3] / / / \ : / / : \_ / : / / / \ : / / : \_ / : / / / \ : / / : \ / : / / [Y4]____[Y1] : / / : [Z2] : / +------:-------:---:--+ +---:---------:-----:-+ ^ vNet1 : : : : : : vNet2 | : : : : : : |(1) : +-------:---:-----:------------:-----:-----+ | : / [X1]__:___:___________[X2] : / | :/ / \_ : : _____/ / : / | : / \_ : _____/ / : / /: / \: / / : / / : / [X5] / : / / : / __/ \__ / : / / : / ___/ \__ / : / / : / ___/ \ / : / / [X4]__________________[X3]..: / +------------------------------------------+ L3 Topology The following steps are performed to deliver the service within the network management automation architecture proposed in this document: o Pre-provision multiple virtualized networks on top of the same basic network infrastructure based on pre-configured service requirements and establish resource pool for each virtualized network and expose to the customer with several service templates through web portal. Wu, et al. Expires December 21, 2019 [Page 25] Internet-Draft Service and Network Management Automation June 2019 o Selects and uses one which fulfills most its requirement among the service templates. o Create resource facing VN Network based on selected service template, and calculate the node resource, link resource corresponding to connectivity between sites. o Setup tunnels between sites and map them into the selected virtualized network topology and establish resource facing VN topology based on TEAS VN model [I-D.ietf-teas-actn-vn-yang] and TE tunnel based on TE Tunnel model. The resource facing VN model and corresponding TE Tunnel model can be further used to notify all the parameter changes and event related to VN topology or Tunnel. These information can be further used to adjust network resource distributed in the network. The network initiated resource creation is similar to ready made Network Slice creation pattern discussed in Section 5.1 of [I- D.homma-slice-provision-models]. 6.2. Customer-initiated Dynamic Resource Creation Wu, et al. Expires December 21, 2019 [Page 26] Internet-Draft Service and Network Management Automation June 2019 |(2) | V +-------------------+ | Management System | (3)(4)(5) +-------------------+ +--------------------------------------------------------+ / _[CE2] _[CE3] / / _/ : \_ _/ : \_ / / _/ : \_ _/ : \_ / / _/ : \_ _/ : \_ / / / : \ / : \ / /[CE1]_________________[PE1] [PE2]_________________[CE4] / +---------:--------------:------------:--------------:---+ "Service" -------------------------------------------------------------------- "Resource" ^ : | : : : |(1) : +-------:---:-----:------------:-----:-----+ | : / [X1]__:___ __________[X2] / | :/ / \_ : _____/ / / | : / \_ : _____/ / / /: / \: / / / / : / [X5] / / / : / __/ \__ / / / : / ___/ \__ / / / : / ___/ \ / / / [X4]__________________[X3]. / +------------------------------------------+ L3 Topology The following steps are performed to deliver the service within the network management automation architecture proposed in this document: o Establish resources pool for the basic common network infrastructure. o Request to create two sites based on 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 Wu, et al. Expires December 21, 2019 [Page 27] Internet-Draft Service and Network Management Automation June 2019 o Create a new service topology based on Service Type and service requirements (e.g., Slice Service Type, Slice location, Number of Slices, QoS requirements corresponding to network connectivity within a Slice) defined in L3SM service model. o Translate L3SM service model into resource facing TEAS VN Model [I-D.ietf-teas-actn-vn-yang], and calculate the node resource, link resource corresponding to connectivity between sites or connectivity between PE and CE within Site in the service topology based on generated resource facing TEAS VN model. o Setup tunnels between sites and tunnel between PE and CE within Site and map them into basic network infrastructure and establish resource facing VN topology based on TEAS VN model and TE tunnel based on TE Tunnel model. The resource facing TEAS VN model and corresponding TE Tunnel model can be used to notify all the parameter changes and event related to VN topology or Tunnel. These information can be further used to adjust network resource distributed within the network. The customer initiated resource creation is similar to customer made Network Slice creation pattern discussed in Section 5.2 of [I- D.homma-slice-provision-models]. 7. 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 8. IANA Considerations There are no IANA requests or assignments included in this document. Wu, et al. Expires December 21, 2019 [Page 28] Internet-Draft Service and Network Management Automation June 2019 9. Contributors Shunsuke Homma Japan Email: s.homma0718+ietf@gmail.com 10. Acknowledgements Thanks to Joe Clarck and Greg Mirsky for the review. 11. 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- diffserv-model-03 (work in progress), June 2015. [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.evenwu-opsawg-yang-composed-vpn] Even, R., Bo, W., Wu, Q., and Y. Cheng, "YANG Data Model for Composed VPN Service Delivery", draft-evenwu-opsawg- yang-composed-vpn-03 (work in progress), March 2019. [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-00 (work in progress), February 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. Wu, et al. Expires December 21, 2019 [Page 29] Internet-Draft Service and Network Management Automation June 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-09 (work in progress), October 2018. [I-D.ietf-bess-l3vpn-yang] Jain, D., Patel, K., Brissette, P., Li, Z., Zhuang, S., Liu, X., Haas, J., Esale, S., and B. Wen, "Yang Data Model for BGP/MPLS L3 VPNs", draft-ietf-bess-l3vpn-yang-04 (work in progress), October 2018. [I-D.ietf-bfd-yang] Rahman, R., Zheng, L., Jethanandani, M., Networks, J., and G. Mirsky, "YANG Data Model for Bidirectional Forwarding Detection (BFD)", draft-ietf-bfd-yang-17 (work in progress), August 2018. [I-D.ietf-ccamp-alarm-module] 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., Dios, O., King, D., Lee, Y., and G. Galimberti, "YANG data model for Flexi-Grid Optical Networks", draft-ietf-ccamp-flexigrid- yang-03 (work in progress), March 2019. [I-D.ietf-ccamp-l1csm-yang] Fioccola, G., Lee, K., Lee, Y., Dhody, D., and D. Ceccarelli, "A YANG Data Model for L1 Connectivity Service Model (L1CSM)", draft-ietf-ccamp-l1csm-yang-09 (work in progress), March 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", draft-ietf-ccamp-mw-yang-13 (work in progress), November 2018. Wu, et al. Expires December 21, 2019 [Page 30] Internet-Draft Service and Network Management Automation June 2019 [I-D.ietf-ccamp-otn-topo-yang] Zheng, H., Guo, A., Busi, I., Sharma, A., Liu, X., Belotti, S., Xu, Y., Wang, L., and O. Dios, "A YANG Data Model for Optical Transport Network Topology", draft-ietf- ccamp-otn-topo-yang-06 (work in progress), February 2019. [I-D.ietf-ccamp-otn-tunnel-model] Zheng, H., Guo, A., Busi, I., Sharma, A., Rao, R., Belotti, S., Lopezalvarez, V., Li, Y., and Y. Xu, "OTN Tunnel YANG Model", draft-ietf-ccamp-otn-tunnel-model-06 (work in progress), February 2019. [I-D.ietf-ccamp-wson-tunnel-model] Lee, Y., Dhody, D., Guo, A., Lopezalvarez, V., King, D., Yoon, B., and R. Vilata, "A Yang Data Model for WSON Tunnel", draft-ietf-ccamp-wson-tunnel-model-03 (work in progress), March 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-29 (work in progress), May 2019. [I-D.ietf-dots-signal-channel] K, R., 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-34 (work in progress), May 2019. [I-D.ietf-idr-bgp-model] Jethanandani, M., Patel, K., and S. Hares, "BGP YANG Model for Service Provider Networks", draft-ietf-idr-bgp- model-06 (work in progress), June 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-03 (work in progress), March 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. Wu, et al. Expires December 21, 2019 [Page 31] Internet-Draft Service and Network Management Automation June 2019 [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-10 (work in progress), February 2019. [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. [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, Y., and f. hu, "A YANG Data Model for Protocol Independent Multicast (PIM)", draft-ietf-pim-yang-17 (work in 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-06 (work in progress), March 2019. [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-12 (work in progress), February 2019. Wu, et al. Expires December 21, 2019 [Page 32] Internet-Draft Service and Network Management Automation June 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-05 (work in progress), June 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. [I-D.ietf-teas-te-service-mapping-yang] Lee, Y., Dhody, D., Ceccarelli, D., Tantsura, J., Fioccola, G., and Q. Wu, "Traffic Engineering and Service Mapping Yang Model", draft-ietf-teas-te-service-mapping- yang-01 (work in progress), March 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-04 (work in progress), March 2019. [I-D.ietf-teas-yang-path-computation] Busi, I., Belotti, S., Lopezalvarez, V., Dios, O., Sharma, A., Shi, Y., Vilata, R., Sethuraman, K., Scharf, M., and D. Ceccarelli, "Yang model for requesting Path Computation", draft-ietf-teas-yang-path-computation-05 (work in progress), March 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-06 (work in progress), April 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-04 (work in progress), March 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-21 (work in progress), April 2019. Wu, et al. Expires December 21, 2019 [Page 33] Internet-Draft Service and Network Management Automation June 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-21 (work in progress), May 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 LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007, . [RFC4762] Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007, . [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, . [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined Networking: A Perspective from within a Service Provider Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014, . [RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y. Weingarten, "An Overview of Operations, Administration, and Maintenance (OAM) Tools", RFC 7276, DOI 10.17487/RFC7276, June 2014, . [RFC7297] Boucadair, M., Jacquenet, C., and N. Wang, "IP Connectivity Provisioning Profile (CPP)", RFC 7297, DOI 10.17487/RFC7297, July 2014, . Wu, et al. Expires December 21, 2019 [Page 34] Internet-Draft Service and Network Management Automation June 2019 [RFC8077] Martini, L., Ed. and G. Heron, Ed., "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", STD 84, RFC 8077, DOI 10.17487/RFC8077, February 2017, . [RFC8194] Schoenwaelder, J. and V. Bajpai, "A YANG Data Model for LMAP Measurement Agents", RFC 8194, DOI 10.17487/RFC8194, August 2017, . [RFC8199] Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module Classification", RFC 8199, DOI 10.17487/RFC8199, July 2017, . [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, . [RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018, . [RFC8328] Liu, W., Xie, C., Strassner, J., Karagiannis, G., Klyus, M., Bi, J., Cheng, Y., and D. Zhang, "Policy-Based Management Framework for the Simplified Use of Policy Abstractions (SUPA)", RFC 8328, DOI 10.17487/RFC8328, March 2018, . [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, . [RFC8346] Clemm, A., Medved, J., Varga, R., Liu, X., Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346, March 2018, . [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for Routing Management (NMDA Version)", RFC 8349, DOI 10.17487/RFC8349, March 2018, . [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, . Wu, et al. Expires December 21, 2019 [Page 35] Internet-Draft Service and Network Management Automation June 2019 [RFC8512] Boucadair, M., Ed., Sivakumar, S., Jacquenet, C., Vinapamula, S., and Q. Wu, "A YANG Module for Network Address Translation (NAT) and Network Prefix Translation (NPT)", RFC 8512, DOI 10.17487/RFC8512, January 2019, . [RFC8513] Boucadair, M., Jacquenet, C., and S. Sivakumar, "A YANG Data Model for Dual-Stack Lite (DS-Lite)", RFC 8513, DOI 10.17487/RFC8513, January 2019, . [RFC8519] Jethanandani, M., Agarwal, S., Huang, L., and D. Blair, "YANG Data Model for Network Access Control Lists (ACLs)", RFC 8519, DOI 10.17487/RFC8519, March 2019, . [RFC8528] Bjorklund, M. and L. Lhotka, "YANG Schema Mount", RFC 8528, DOI 10.17487/RFC8528, March 2019, . [RFC8529] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X. Liu, "YANG Data Model for Network Instances", RFC 8529, DOI 10.17487/RFC8529, March 2019, . [RFC8530] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X. Liu, "YANG Model for Logical Network Elements", RFC 8530, DOI 10.17487/RFC8530, March 2019, . [RFC8531] Kumar, D., Wu, Q., and Z. Wang, "Generic YANG Data Model for Connection-Oriented Operations, Administration, and Maintenance (OAM) Protocols", RFC 8531, DOI 10.17487/RFC8531, April 2019, . [RFC8532] Kumar, D., Wang, Z., Wu, Q., Ed., Rahman, R., and S. Raghavan, "Generic YANG Data Model for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications", RFC 8532, DOI 10.17487/RFC8532, April 2019, . Wu, et al. Expires December 21, 2019 [Page 36] Internet-Draft Service and Network Management Automation June 2019 [RFC8533] Kumar, D., Wang, M., Wu, Q., Ed., Rahman, R., and S. Raghavan, "A YANG Data Model for Retrieval Methods for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications", RFC 8533, DOI 10.17487/RFC8533, April 2019, . Authors' Addresses Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: bill.wu@huawei.com Mohamed Boucadair Orange Rennes 35000 France Email: mohamed.boucadair@orange.com Young Lee Futurewei Email: younglee.tx@gmail.com Wu, et al. Expires December 21, 2019 [Page 37]