TEAS LM. Contreras Internet-Draft Telefonica Intended status: Informational R. Rokui Expires: September 7, 2022 Ciena J. Tantsura Microsoft B. Wu Huawei X. Liu IBM Corporation D. Dhody Huawei S. Belloti Nokia March 6, 2022 IETF Network Slice Controller and its associated data models draft-contreras-teas-slice-controller-models-02 Abstract This document describes the 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 slices and their realization. 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 September 7, 2022. Contreras , et al. Expires September 7, 2022 [Page 1] Internet-Draft Slice Controller and its data models March 2022 Copyright Notice Copyright (c) 2022 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. IETF Network Slice data models . . . . . . . . . . . . . . . 3 3. Structure of the IETF Network Slice Controller (NSC) . . . . 4 3.1. NS Mapper . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2. NS Realizer . . . . . . . . . . . . . . . . . . . . . . . 7 4. Model types in IETF Network Slice Controller interfaces . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction Editor's Note: the terminology in this draft will be aligned with the final terminology selected for describing the notion of IETF Network Slice when applied to IETF technologies, which is currently under discussion. By now same terminology as used in [I-D.nsdt-teas-ietf-network-slice-definition] and [I-D.nsdt-teas-ns-framework] is primarily used here. Consensus to use "IETF Network Slice" term has been reached. The generic idea of network slicing intends to provide tailored end- to-end network capabilities to customers in the way that they could be perceived as a dedicated network, despite the fact that it makes use of shared physical infrastructure facilities. Among the capabilities mentioned, connectivity of different parts of a network slice with particular characteristics play a central role. Thus, the concept of IETF Network Slice, realized by any of the IETF technologies, emerges as complementary but essential part of an end- to-end network slice. Contreras , et al. Expires September 7, 2022 [Page 2] Internet-Draft Slice Controller and its data models March 2022 In order to facilitate the request, realization and lifecycle control and management of a transport slice, a new element named IETF Network Slice Controller (NSC) is being proposed in [I-D.nsdt-teas-ietf-network-slice-definition] and [I-D.nsdt-teas-ns-framework]. The NSC from its North Bound Interface (NBI) exposes set of APIs that allow a higher level system to request an end-to-end transport slice. It receives the request of enablement of an IETF Network Slice by a customer (i.e. creation, modification or deletion). Upon receiving a request from its NBI, NSC finds the resources needed for realization of the IETF Network Slice and in turn interfaces from its South Bound Interface (SBI) with one or more Network Controllers for the realization of the requested IETF Network Slice request and the management of its lifecycle. Figure 1 presents a high-level view of the TSC. +------------------------------------------+ | A higher level system | | (e.g E2E network slice orchestrator) | +------------------------------------------+ A | NSC NBI V +------------------------------------------+ | IETF Network Slice Controller (NSC) | +------------------------------------------+ A | NSC SBI V +------------------------------------------+ | Network Controller(s) | +------------------------------------------+ Figure 1: Interface of Transport Slice Controller This memo describes the characteristics of the NSC as well as a detailed structure of the NSC and its major components. In addition, it describes the characteristics of the data models to identify the IETF Network Slice and its realization. Then the data models referred are mapped to the interfaces among components. 2. IETF Network Slice data models At the time of provisioning and operating IETF Network Slices different views can be identified as necessary: Contreras , et al. Expires September 7, 2022 [Page 3] Internet-Draft Slice Controller and its data models March 2022 o Customer's view, mostly focused on the individual IETF Network Slice request process, reflecting the needs of each particular customer, including SLOs and other characteristics of the slice relevant for it. This view is technology agnostics and describes the characteristics of the IETF Network Slice from a customer's point of view. It can include the slice topology, performance parameters, endpoints of the slice, traffic characteristics of the slice, and the KPIs to monitor the slice. o Provider's view, mostly focused on the provisioning and operation of the IETF Network Slices in the transport network, considering how a particular IETF Network Slice interplays with other IETF Network Slices maintained by the provider on a shared infrastructure. In other words, operator's view shows how an IETF Network Slice is realized in operator's network along with all the resources used during the its realization. Both views are complementary, each of them specialized for a given purpose. In consequence, it should be consistency between both in order to ensure alignment. Currently there are two different models proposed, on for each of the categories above. The model in [I-D.wd-teas-ietf-network-slice-nbi-yang] fits into the customer view, while the model defined in [I-D.liu-teas-transport-network-slice-yang] fits in to the provider view. It should be noted that for the realization of a transport slice, the NSC interacts with one or more Network Controllers. In that case, the data models to be used are particular for each Network Controller (e.g., technology dependent), as well as the mapping function from its NBI to SBI and the details of this mapping function are both out of the scope of this document. 3. Structure of the IETF Network Slice Controller (NSC) The NSC should work with both data models. The NSC takes first the customer's view by analyzing the needs of the customer, processing such requests taking into account the overall view of the network and the IETF Network Slices already instantiated, normalizing its instantiation across different technologies, and finally generates the provider view. Once the new request is processed and declared as feasible, the NSC triggers its realization by interacting with the Network Controllers and communicates back to the higher level controller to start the billing cycle. Contreras , et al. Expires September 7, 2022 [Page 4] Internet-Draft Slice Controller and its data models March 2022 In order to accommodate these procedures, the internal structure of the NSC can be divided into: o IETF Network Slice Mapper: this high-level component processes the customer request, putting it into the context of the overall IETF Network Slices in the network. o IETF Network Slice Realizer: this high-level component processes the complete view of transport slices including the one requested by the customer, decides the proper technologies for realizing the IETF Network Slice and triggers its realization. Figure 2 illustrates the components described and the associated models, as follows o (a) -> customer's view, e.g. [I-D.wd-teas-ietf-network-slice-nbi-yang]. o (b) -> provider's view, including more detailed but yet technology-agnostic resource view as e.g. [I-D.liu-teas-transport-network-slice-yang], and/or alternative technology-specific augmentations as e.g. [I-D.ietf-ccamp-yang-otn-slicing]. o (c) -> models per network controller, out of scope of this document Contreras , et al. Expires September 7, 2022 [Page 5] Internet-Draft Slice Controller and its data models March 2022 Higher Level System | | --------------------------- | NSC | (a) | | v | | ------------------- | | | | | | | NS Mapper | | | | | | | ------------------- | | | (b) | | v | | ------------------- | | | | | | | NS Realizer | | | | | | | ------------------- | | | (c) | --------------------------- | v Network Controllers Figure 2: IETF Network Slice Controller structure and asspociated data models IETF Network Slices with different level of detail could be requested: o The IETF network slice can be abstracted as a set of edge-to-edge links (Type 1). o The IETF network slice can be abstracted as a topology of virtual nodes and virtual links (Type 2) which represent the partitioning of underlay network resources for use by network slice connectivity. The use cases of these two types of networks are further described by [RFC8453]. [I-D.wd-teas-ietf-network-slice-nbi-yang] models the Type 1 service, while [I-D.liu-teas-transport-network-slice-yang] models the Type 2 service. When a customer intends to request a Type 2 service, [I-D.liu-teas-transport-network-slice-yang] can also be used at the point (a) in Figure 2. As an example, when ACTN is used to realize an IETF network slice, model mappings are described in more details in [I-D.ietf-teas-actn-yang]. Contreras , et al. Expires September 7, 2022 [Page 6] Internet-Draft Slice Controller and its data models March 2022 3.1. NS Mapper The Mapper will receive the IETF Network Slice request from the customer. It will process it obtaining an overall view of how this new request complements or fits with the rest of IETF Network Slices, if any, as provisioned in the network. As part of that processing, a single customer IETF Network Slice request could result in the need of actually provisioning different IETF Network Slices in the network. The Mapper will maintain the relationship among customer IETF Network Slice request and provisioned IETF Network Slices. 3.2. NS Realizer The Realizer will receive from the Mapper one or more requests for provision of IETF Network Slices, potentially including some technology-specific information. With that information, the Realizer will determine the realization of each particular IETF Network Slice interacting with technology-specific Network Controllers. 4. Model types in IETF Network Slice Controller interfaces Both [RFC8309] and [RFC8969] offer a complete view of customer, service and network model types. In this sense a potential mapping of models to IETF Network Slcie Controller interfaces is as follows: o NBI of the IETF NSC (interface (a) in Figure 2) -> Customer service model. According to [RFC8309] "a customer's service request is (or should be) technology agnostic. That is, a customer is unaware of the technology that the network operator has available to deliver the service, so the customer does not make requests specific to the underlying technology but is limited to making requests specific to the service that is to be delivered". This definition matches the expected behavior of the IETF NSC NBI as considered in in [I-D.nsdt-teas-ietf-network-slice-definition] and [I-D.nsdt-teas-ns-framework]. o Interface between NS Mapper and NS Realizer (interface (b) in Figure 2) -> Service Delivery model. According to [RFC8309] "a service delivery module is expressed as a core set of parameters that are common across a network type and technology [...] Service delivery modules include technology-specific modules.". Furthermore, [RFC8969] (in its Figures 3 and 5) considers L3SM or VN Service models to be later on fed into a controller. o SBI of the IETF NSC (interface (c) in Figure 2) -> Network Configuration model. According to [RFC8309] "the orchestrator must map the service request to its view, and this mapping may Contreras , et al. Expires September 7, 2022 [Page 7] Internet-Draft Slice Controller and its data models March 2022 include a choice of which networks and technologies to use depending on which service features have been requested". This is coincideent with the expected behavior of the IETF NSC SBI as considered in in [I-D.nsdt-teas-ietf-network-slice-definition] and [I-D.nsdt-teas-ns-framework]. 5. Security Considerations To be done. 6. IANA Considerations This draft does not include any IANA considerations 7. References [I-D.ietf-ccamp-yang-otn-slicing] Guo, A., Contreras, L. M., Belotti, S., Rokui, R., Xu, Y., Zhao, Y., and X. Liu, "Framework and Data Model for OTN Network Slicing", draft-ietf-ccamp-yang-otn-slicing-01 (work in progress), March 2022. [I-D.ietf-teas-actn-yang] Lee, Y., Zheng, H., Ceccarelli, D., Yoon, B. Y., and S. Belotti, "Applicability of YANG models for Abstraction and Control of Traffic Engineered Networks", draft-ietf-teas- actn-yang-08 (work in progress), September 2021. [I-D.liu-teas-transport-network-slice-yang] Liu, X., Tantsura, J., Bryskin, I., Contreras, L. M., Wu, Q., Belotti, S., and R. Rokui, "IETF Network Slice YANG Data Model", draft-liu-teas-transport-network-slice- yang-04 (work in progress), July 2021. [I-D.nsdt-teas-ietf-network-slice-definition] Rokui, R., Homma, S., Makhijani, K., Contreras, L. M., and J. Tantsura, "Definition of IETF Network Slices", draft- nsdt-teas-ietf-network-slice-definition-02 (work in progress), December 2020. [I-D.nsdt-teas-ns-framework] Gray, E. and J. Drake, "Framework for IETF Network Slices", draft-nsdt-teas-ns-framework-05 (work in progress), February 2021. Contreras , et al. Expires September 7, 2022 [Page 8] Internet-Draft Slice Controller and its data models March 2022 [I-D.wd-teas-ietf-network-slice-nbi-yang] Wu, B., Dhody, D., Rokui, R., Saad, T., Han, L., and L. M. Contreras, "IETF Network Slice Service YANG Model", draft- wd-teas-ietf-network-slice-nbi-yang-05 (work in progress), September 2021. [RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018, . [RFC8453] Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for Abstraction and Control of TE Networks (ACTN)", RFC 8453, DOI 10.17487/RFC8453, August 2018, . [RFC8969] Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and L. Geng, "A Framework for Automating Service and Network Management with YANG", RFC 8969, DOI 10.17487/RFC8969, January 2021, . Authors' Addresses Luis M. Contreras Telefonica Ronda de la Comunicacion, s/n Sur-3 building, 3rd floor Madrid 28050 Spain Email: luismiguel.contrerasmurillo@telefonica.com URI: http://lmcontreras.com/ Reza Rokui Ciena Canada Email: rrokui@ciena.com Jeff Tantsura Microsoft USA Email: jefftant.ietf@gmail.com Contreras , et al. Expires September 7, 2022 [Page 9] Internet-Draft Slice Controller and its data models March 2022 Bo Wu Huawei Technologies 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: lana.wubo@huawei.com Xufeng Liu IBM Corporation Email: xufeng.liu.ietf@gmail.com Dhruv Dhody Huawei Technologies Divyashree Techno Park Bangalore, Karnataka 560066 India Email: dhruv.ietf@gmail.com Sergio Belloti Nokia Email: sergio.belotti@nokia.com Contreras , et al. Expires September 7, 2022 [Page 10]