Alef Edge

xufeng.liu.ietf@gmail.com

Microsoft

jefftant.ietf@gmail.com

Individual

i_bryskin@yahoo.com

Telefonica

luismiguel.contrerasmurillo@telefonica.com

Huawei

bill.wu@huawei.com

Nokia

Sergio.belotti@nokia.com

Ciena

rrokui@ciena.com

Futurewei

aihuaguo.ietf@gmail.com

Huawei

italo.busi@huawei.com

TEAS Working Group An IETF network slice may use a customized topology to describe intended resource reservation for connectivities between slice endpoints. Customized topologies enable customers to request shared resources among connections activated on demand and to customize the service paths in a network slice with an extensive level of control. This document describes a YANG data model for managing and controlling customized topologies for IETF network slices defined in RFC YYYY. [RFC EDITOR NOTE: Please replace RFC YYYY with the RFC number of draft-ietf-teas-ietf-network-slices once it has been published.

Introduction describes that an IETF network slice service customer might ask for some level of control, e.g., to customize the service paths while requesting network slice services. These customized controls may well be expressed by customer-defined topologies, i.e. customized topologies. Furthermore, by using customized topologies, customers can request advanced resource reservation for all potential network slices that can be activated on demand in the future. This capability provides customers with full control over when and how resources are allocated by the slices. The resources can be shared by network slices created at different times as well as by connections between different edge pairs within the same network slice. This could significantly reduce the overall bandwidth requirements of a network slice and provide economic advantages to the customer. For example, in a hub-and-spoke network slice scenario, multiple customer's spoke sites are expected to be dynamically connected to the hub site and the bandwidth is shared between the spoke sites. To create a customized topology with two virtual nodes, one representing all the spoke sites and the other representing the hub site, connected by a shared link between the two, can ensure that resources for the shared connection are reserved in advance and hence are readily available whenever needed by the customer. On the other hand, to achieve the same level of bandwidth assurance with connections, it would be necessary to create separate, dedicated connections between every spoke and the hub. However, this would result in significant waste of bandwidth. This document defines a YANG data model for representing, managing, and controlling IETF network slices over customized network topologies, where the network slices are defined in . The YANG model augments the data model defined in to enable a customer to express desired service-level objectives (SLOs) and service-level expectations (SLEs) over various constructs within the customized topology. The defined data model is an interface between customers and providers for configurations and state retrievals, so as to support network slicing as a service. Through this model, a customer can request or negotiate with a network slicing provider to create an instance. The customer can incrementally update its requirements on individual topology elements in the slice instance, e.g., adding or removing a node or link, updating desired bandwidth of a link, and retrieve the operational states of these elements. With the help of other mechanisms and data models defined in IETF, the telemetry information can be published to the customer, too. The YANG model defines constructs that are technology-agnostic to network slicing built on network layers with different technologies such as IP/MPLS, MPLS-TP, OTN and WDM optical. Therefore, this model can serve as a common and base model on which technology-specific models for network slicing, such as , may be built. As described in Section 3 of , using customized topologies and control of resource reservation is optional for network slicing and complements the data model defined in . The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) .

Terminologies and Notations The following terminologies for describing network slices are defined in and are not redefined herein. Network Slice (NS) Network Slice Customer Network Slice Service Provider Network Slice Controller (NSC) Network Resource Partition (NRP) The following terms are defined and used in this document. Customized Topology: A topology defined by the customer and served as an input to the network slice service provider, i.e. to the Network Slice Controller (NSC). Abstract Topology: A topology exposed to the customer by the network slice service provider prior to the creation of network slices. The provider uses an abstract topology to expose useful information, such as available resources to the customer, which can facilitate the build-up of customized topologies by the customer. NRP Topology: A topology internal to the NSC to facilitate the mapping of network slices to underlying network resources.

Tree Diagram Tree diagrams used in this document follow the notation defined in .

Prefixes in Data Node Names In this document, names of data nodes and other data model objects are prefixed using the standard prefix associated with the corresponding YANG imported modules, as shown in . Prefix YANG Module Reference yang ietf-yang-types inet ietf-inet-types nt ietf-network-topology nw ietf-network-topology tet ietf-te-topology ns-topo ietf-ns-topo [RFCXXXX] te-types ietf-te-types [RFCYYYY] ietf-nss ietf-network-slice-service [RFCZZZZ] RFC Editor Note: Please replace XXXX with the RFC number assigned to this document. Please replace YYYY with the RFC number assigned to . Please replace ZZZZ with the RFC number assigned to . Please remove this note.

Modeling Considerations An IETF network slice topology is a customized topology modeled as network topology defined in , with augmentations. A new network type "network-slice" is defined in this document.
When a network topology data instance contains the network-slice network type, it represents an instance of an IETF network slice topology.

Relationships to Related Topology Models There are several related YANG data models that have been defined in IETF. Some of these are: Network Topology Model: Defined in . Network Slicing Model: Defined in . OTN Slicing: Defined in . shows the relationships among these models. The box of dotted lines denotes the model defined in this document.

-----------------: Topology : | | : Model : +----------+ '''''''''''' ]]>

Model Applicability There are many technologies to achieve network slicing. The data model defined in this document can be used to configure resource-based network slices, where the resources for network slices are reserved and represented in the form of a customized topology, which can then be mapped to a network resource partition (NRP) according to the scenarios defined in . Network slices may be abstracted differently depending on the requirement of the network slice customer. A customer may request a network slice with direct connectivity between pairs of service demarcation points (SDPs). Each connection within the network slice may be further supported by an end-to-end tunnel that traverse a specific path in a given customized topology supplied by the customer. The resources associated with a link are immediately commissioned by the realization at the time of network slice configuration. Alternatively, a customer can request resources to be reserved for potential network slices through a customized topology, and use the resources to build network slices in the future. The customized topology represents resources that are reserved but not commissioned at the time of request. By doing so, customers can share resources between multiple endpoints and use them on demand. In the example shown in , two customized topology intents named as Network Slice Blue and Network Slice Red, are created by separate customers and delivered to the network slice service provider. The provider maps the two intents to corresponding network resource partitions (NRPs) internally. In realizing the network resource partitions, node virtualization is used to separate and allocate resources in physical devices. Two virtual routers VR1 and VR2 are created over physical router R1, and two virtual routers VR3 and VR4 are created over physical router R2, respectively. Each of the virtual routers,as a partition of the physical router, takes a portion of the resources such as ports and memory in the physical router.
Depending on the requirements and the implementations, they may share certain resources such as processors, ASICs, and switch fabric. A network slice customer can configure customized topologies without any prior knowledge of the provider's network and resource availability. However, this could potentially make it difficult for the provider to understand and realize the topology. Alternatively, the provider may choose to describe the available resources and capabilities as an abstract topology and expose it to the customer prior to network slice requests. This can facilitate the customer with building customized topologies and avoid unnecessary negotiations between the customer and provider. The process and the data models for the provider to expose abstract topologies are outside the scope of this document. The provider reports the operational state of the topology, which represents the allocated resources agreed upon through negotiations between the customer and the provider. Customers can subquently process the requested topology and integrate it into their own topology. It's important to note that this relationship between the customer and provider can be recursive. For example, a customer for network slices can be a provider of its own to offer network slice services using customized topologies to its own customers further up the hierarchy. As an example, Appendix B. shows the JSON encoded data instances of the customer topology intent for Network Slice Blue.

YANG Model Overview The following constructs and attributes are defined within the YANG model: Network topology, which represent set of shared, reserved resources organized as a virtual topology between all of the endpoints. A customer could use such network topology to define detailed connectivity path traversing the topology, and allow sharing of resources between its multiple endpoint pairs. Service-level objectives (SLOs) associated with different objects, including node, link, termination point of the topology.

Model Tree Structure

/nw:networks/network/network-id +--rw explicit-path* [tp-id] +--rw tp-id -> /nw:networks/network/node/nt:termination-point/tp-id augment /ietf-nss:network-slice-services/ietf-nss:slice-service /ietf-nss:connection-groups/ietf-nss:connection-group /ietf-nss:connectivity-construct/ietf-nss:slo-sle-policy /ietf-nss:custom/ietf-nss:service-slo-sle-policy /ietf-nss:sle-policy/ietf-nss:steering-constraints: +--rw disjointness? te-types:te-path-disjointness augment /ietf-nss:network-slice-services/ietf-nss:slice-service /ietf-nss:connection-groups/ietf-nss:connection-group /ietf-nss:connectivity-construct/ietf-nss:slo-sle-policy /ietf-nss:custom/ietf-nss:service-slo-sle-policy /ietf-nss:sle-policy/ietf-nss:steering-constraints /ietf-nss:path-constraints: +--rw topology-id? -> /nw:networks/network/network-id +--rw explicit-path* [tp-id] +--rw tp-id -> /nw:networks/network/node/nt:termination-point/tp-id augment /ietf-nss:network-slice-services/ietf-nss:slice-service /ietf-nss:connection-groups/ietf-nss:connection-group /ietf-nss:connectivity-construct/ietf-nss:type /ietf-nss:a2a/ietf-nss:a2a-sdp/ietf-nss:slo-sle-policy /ietf-nss:custom/ietf-nss:service-slo-sle-policy /ietf-nss:sle-policy/ietf-nss:steering-constraints: +--rw disjointness? te-types:te-path-disjointness augment /ietf-nss:network-slice-services/ietf-nss:slice-service /ietf-nss:connection-groups/ietf-nss:connection-group /ietf-nss:connectivity-construct/ietf-nss:type /ietf-nss:a2a/ietf-nss:a2a-sdp/ietf-nss:slo-sle-policy /ietf-nss:custom/ietf-nss:service-slo-sle-policy /ietf-nss:sle-policy/ietf-nss:steering-constraints /ietf-nss:path-constraints: +--rw topology-id? -> /nw:networks/network/network-id +--rw explicit-path* [tp-id] +--rw tp-id -> /nw:networks/network/node/nt:termination-point/tp-id ]]>

YANG Modules

file "ietf-ns-topo@2023-07-07.yang" module ietf-ns-topo { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ns-topo"; prefix "ns-topo"; import ietf-network { prefix "nw"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-network-topology { prefix "nt"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-te-types { prefix "te-types"; reference "draft-ietf-teas-rfc8776-update-04: Common YANG Data Types for Traffic Engineering"; } import ietf-network-slice-service { prefix "ietf-nss"; reference "draft-ietf-teas-ietf-network-slice-nbi-yang-05: IETF Network Slice Service YANG Model"; } organization "IETF CCAMP Working Group"; contact "WG Web: WG List: Editor: Xufeng Liu Editor: Italo Busi Editor: Aihua Guo Editor: Sergio Belotti Editor: Luis M. Contreras "; description "This module defines a base YANG data model for configuring generic network slices in optical transport networks, e.g., Optical Transport Network (OTN). The model fully conforms to the Network Management Datastore Architecture (NMDA). Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2023-07-07 { description "Initial revision"; reference "RFC XXXX: IETF Network Slice Topology YANG Data Model"; } /* * Groupings */ grouping ns-topo-steering-constraints { description "Policy grouping for specifying steering constraints for Transport Network Slices."; leaf disjointness { type te-types:te-path-disjointness; description "Indicate the level of disjointness for slice resources."; } } grouping topology-ref { description "Grouping for network topology reference."; leaf topology-id { type leafref { path "/nw:networks/nw:network/nw:network-id"; } description "Relative reference to network slice topology id."; } uses explicit-path; } grouping explicit-path { description "Explicit path for a connectivity matrix entry"; list explicit-path { key "tp-id"; description "List of TPs within a network topology that form a path."; leaf tp-id { type leafref { path "/nw:networks/nw:network/nw:node"+ "/nt:termination-point/nt:tp-id"; } description "Relative reference to TP id."; } } } /* * Augmented data nodes */ /* network type augments */ augment "/nw:networks/nw:network/nw:network-types" { description "Defines the Network Slice topology type."; container network-slice { presence "Indicates Network Slice topology"; description "Its presence identifies the Network Slice type."; } } /* network topology augments */ augment "/nw:networks/nw:network" { when "./nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment topology configuration and state."; uses ietf-nss:service-slo-sle-policy; } augment "/nw:networks/nw:network" + "/ns-topo:slo-sle-policy" + "/ns-topo:custom" + "/ns-topo:service-slo-sle-policy" + "/ns-topo:sle-policy" + "/ns-topo:steering-constraints" { when "../../../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment topology configuration and state."; uses ns-topo-steering-constraints; } /* network node augments */ augment "/nw:networks/nw:network/nw:node" { when "../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment node configuration and state."; uses ietf-nss:service-slo-sle-policy; } augment "/nw:networks/nw:network/nw:node" + "/ns-topo:slo-sle-policy" + "/ns-topo:custom" + "/ns-topo:service-slo-sle-policy" + "/ns-topo:sle-policy" + "/ns-topo:steering-constraints" { when "../../../../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment IETF network slice services to include steering constraints for nodes."; uses ns-topo-steering-constraints; } /* network node's termination point augments */ augment "/nw:networks/nw:network/nw:node" + "/nt:termination-point" { when "../../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment node configuration and state."; uses ietf-nss:service-slo-sle-policy; } /* network link augments */ augment "/nw:networks/nw:network/nt:link" { when "../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment link configuration and state."; uses ietf-nss:service-slo-sle-policy; } augment "/nw:networks/nw:network/nt:link" + "/ns-topo:slo-sle-policy" + "/ns-topo:custom" + "/ns-topo:service-slo-sle-policy" + "/ns-topo:sle-policy" + "/ns-topo:steering-constraints" { when "../../../../nw:network-types/ns-topo:network-slice" { description "Augment only for Network Slice topology."; } description "Augment IETF network slice services to include steering constraints for links within a resource-based transport network slice."; uses ns-topo-steering-constraints; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slo-sle-templates" + "/ietf-nss:slo-sle-template" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" { description "Augment IETF network slice service templates with technology-specific steering constraints."; uses ns-topo-steering-constraints; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" { description "Augment IETF network slice services to include steering constraints for connectivity-based transport network slices."; uses ns-topo-steering-constraints; } /* connectivity construct augments */ augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" { description "Augment IETF network slice services to include steering constraints for connectivity-constructs within a connectivity-based transport network slice."; uses ns-topo-steering-constraints; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" + "/ietf-nss:path-constraints" { description "Add toplogy id and explicit path to the connection group"; uses topology-ref; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:connectivity-construct" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" { description "Augment IETF network slice services to include steering constraints for connectivity-constructs within a connectivity-based transport network slice."; uses ns-topo-steering-constraints; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:connectivity-construct" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" + "/ietf-nss:path-constraints" { description "Add toplogy id and explicit path to the connectivity construct"; uses topology-ref; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:connectivity-construct" + "/ietf-nss:type" + "/ietf-nss:a2a" + "/ietf-nss:a2a-sdp" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" { description "Augment IETF network slice services to include steering constraints for a2a connectivity-constructs within a connectivity-based transport network slice."; uses ns-topo-steering-constraints; } augment "/ietf-nss:network-slice-services" + "/ietf-nss:slice-service" + "/ietf-nss:connection-groups" + "/ietf-nss:connection-group" + "/ietf-nss:connectivity-construct" + "/ietf-nss:type" + "/ietf-nss:a2a" + "/ietf-nss:a2a-sdp" + "/ietf-nss:slo-sle-policy" + "/ietf-nss:custom" + "/ietf-nss:service-slo-sle-policy" + "/ietf-nss:sle-policy" + "/ietf-nss:steering-constraints" + "/ietf-nss:path-constraints" { description "Add toplogy id and explicit path to a2a connectivity construct"; uses topology-ref; } } ]]>

Manageability Considerations To ensure the security and controllability of physical resource isolation, slice-based independent operation and management are required to achieve management isolation. Each network slice typically requires dedicated accounts, permissions, and resources for independent access and O&M. This mechanism is to guarantee the information isolation among slice tenants and to avoid resource conflicts. The access to slice management functions will only be permitted after successful security checks.

Security Considerations The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The NETCONF access control model provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. Considerations in Section 8 of are also applicable to their subtrees in the module defined in this document. Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. Considerations in Section 8 of are also applicable to their subtrees in the module defined in this document.

IANA Considerations It is proposed to IANA to assign new URIs from the "IETF XML Registry" as follows:

This document registers a YANG module in the YANG Module Names registry .

YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). This document defines an abstract (generic, or base) YANG data model for network/service topologies and inventories. The data model serves as a base model that is augmented with technology-specific details in other, more specific topology and inventory data models. Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. This document defines a YANG data model for representing, retrieving, and manipulating Traffic Engineering (TE) Topologies. The model serves as a base model that other technology-specific TE topology models can augment. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations. The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] This document defines encoding rules for representing configuration data, state data, parameters of Remote Procedure Call (RPC) operations or actions, and notifications defined using YANG as JavaScript Object Notation (JSON) text. Old Dog Consulting Juniper Networks Ciena NTT Futurewei Telefonica Nvidia This document describes network slicing in the context of networks built from IETF technologies. It defines the term "IETF Network Slice" to describe this type of network slice, and establishes the general principles of network slicing in the IETF context. The document discusses the general framework for requesting and operating IETF Network Slices, the characteristics of an IETF Network Slice, the necessary system components and interfaces, and how abstract requests can be mapped to more specific technologies. The document also discusses related considerations with monitoring and security. This document also provides definitions of related terms to enable consistent usage in other IETF documents that describe or use aspects of IETF Network Slices. Futurewei Technologies Telefonica Nokia Ciena CAICT China Mobile Alef Edge The requirement of slicing network resources with desired quality of service is emerging at every network technology, including the Optical Transport Networks (OTN). As a part of the transport network, OTN can provide hard pipes with guaranteed data isolation and deterministic low latency, which are highly demanded in the Service Level Agreement (SLA). This document describes a framework for OTN network slicing and defines YANG data models with OTN technology-specific augments deployed at both the north and south bound of the OTN network slice controller. Additional YANG data model augmentations will be defined in a future version of this draft. Telefonica Ciena Microsoft Huawei IBM Corporation Huawei Nokia This document describes a potential division in major functional components of an IETF Network Slice Controller (NSC) as well as references the data models required for supporting the requests of IETF network slice services and their realization. This document describes a potential way of structuring the IETF Network Slice Controller as well as how to use different data models being defined for IETF Network Slice Service provision (and how they are related). It is not the purpose of this document to standardize or constrain the implementation the IETF Network Slice Controller. Huawei Technologies Huawei Technologies Ciena Cisco Systems, Inc Cisco Systems, Inc This document defines a YANG data model for the IETF Network Slice Service. The model can be used in the IETF Network Slice Service interface between a customer and a provider that offers IETF Network Slice Services. Huawei Futurewei Technologies Alef Edge Cisco Systems Inc. Individual This document defines a collection of common data types and groupings in YANG data modeling language. These derived common types and groupings are intended to be imported by modules that model Traffic Engineering (TE) configuration and state capabilities. This document obsoletes RFC 8776.

Acknowledgments The authors would like to thank Danielle Ceccarelli, Bo Wu, Mohamed Boucadair, and Vishnu Beeram for providing valuable insights.

Data Tree for the Example in Section 3.1

Native Topology This section contains an example of an instance data tree in the JSON encoding . The example instantiates "ietf-network" for the topology of Network Slice Blue depicted in .