CCAMP Working Group Haomian Zheng Internet Draft Italo Busi Intended status: Standard Track Huawei Technologies Aihua Guo Futurewei Technologies Victor Lopez Telefonica I+D/GCTO Expires: August 2021 February 22, 2021 Framework and Data Model for OTN Network Slicing draft-zheng-ccamp-yang-otn-slicing-01 Abstract The requirement of slicing network resource 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 a YANG data model augmentation of the OTN topology model. Additional YANG data model augmentations will be defined in a future version of this draft. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt Zheng, et al. Expires August 22, 2021 [Page 1] Internet-Draft Framework and YANG of OTN Slices February 2021 The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on August 22, 2021. Copyright Notice Copyright (c) 2021 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 (http://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. Use Cases for OTN Network Slicing..............................3 2.1. Leased Line Services with OTN.............................3 2.2. Co-construction and Sharing...............................3 2.3. Wholesale of optical resources............................4 2.4. Vertical dedicated network with OTN.......................4 3. Framework for OTN slicing......................................5 4. YANG Data Model for OTN Slicing Configuration..................7 4.1. OTN Slicing YANG Model for MPI............................7 4.1.1. MPI YANG Model Overview..............................7 4.1.2. MPI YANG Model Tree..................................7 4.1.3. MPI YANG Code........................................7 4.2. OTN Slicing YANG Model for OTN-SC NBI....................11 5. Manageability Considerations..................................11 6. Security Considerations.......................................11 7. IANA Considerations...........................................11 8. References....................................................12 8.1. Normative References.....................................12 8.2. Informative References...................................12 Acknowledgments..................................................12 Contributors' Addresses..........................................12 Authors' Addresses...............................................13 Zheng, et al. Expires August 22, 2021 [Page 2] Internet-Draft Framework and YANG of OTN Slices February 2021 1. Introduction The requirement of slicing network resource 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 a YANG data model augmentation of the OTN topology model. Additional YANG data model augmentations will be defined in a future version of this draft. 2. Use Cases for OTN Network Slicing 2.1. Leased Line Services with OTN For end business customers (like OTT or enterprises), leased lines have the advantage of providing high-speed connections with low costs. On the other hand, the traffic control of leased lines is very challenging due to rapid changes in service demands. Carriers are recommended to provide network-level slicing capabilities to meet this demand. Based on such capabilities, private network users have full control over the sliced resources which have allocated to them and which could be used to support their leased lines, when needed. Users may formulate policies based on the demand for services and time to schedule the resources from the entire network's perspective flexibly. For example, the bandwidth between any two points may be established or released based on the time or monitored traffic characteristics. The routing and bandwidth may be adjusted at a specific time interval to maximize network resource utilization efficiency. 2.2. Co-construction and Sharing Co-construction and sharing of a network are becoming a popular means among service providers to reduce networking building CAPEX. For Co- construction and sharing case, there are typically multiple co- founders for the same network. For example, one founder may provide optical fibres and another founder may provide OTN equipment, while each occupies a certain percentage of the usage rights of the network resources. In this scenario, the network O&M is performed by a certain founder in each region, where the same founder usually deploys an independent management and control system. The other founders of the network use each other's management and control Zheng, et al. Expires August 22, 2021 [Page 3] Internet-Draft Framework and YANG of OTN Slices February 2021 system to provision services remotely. In this scenario, different founders' network resources need to be automatically (associated) divided, isolated, and visualized. In addition, all founders have independent O&M capabilities, and should be able to perform service- level provisioning in their respective slices. 2.3. Wholesale of optical resources In the optical resource wholesale market, smaller, local carriers and wireless carriers may rent resources from larger carriers, or infrastructure carriers instead of building their networks. Likewise, international carriers may rent resources from respective local carriers and local carriers may lease their owned networks to each other to achieve better network utilization efficiency. From the perspective of a resource provider, it is crucial that a network slice is timely configured to meet traffic matrix requirements requested by its tenants. The support for multi-tenancy within the resource provider's network demands that the network slices are qualitatively isolated from each other to meet the requirements for transparency, non-interference, and security. Typically, a resource purchaser expects to use the leased network resources flexibly, just like they are self-constructed. Therefore, the purchaser is not only provided with a network slice, but also the full set of functionalities for operating and maintaining the network slice. The purchaser also expects to, in a flexible and independent manner, schedule and maintain physical resources to support their own end-to-end automation using both leased and self-constructed network resources. 2.4. Vertical dedicated network with OTN Vertical industry slicing is an emerging category of network slicing due to the high demand for private high-speed network interconnects for industrial applications. In this scenario, the biggest challenge is to implement differentiated optical network slices based on the requirements from different industries. For example, in the financial industry, to support high-frequency transactions, the slice must ensure to provide the minimum latency along with the mechanism for latency management. For the healthcare industry, online diagnosis network and software capabilities to ensure the delivery of HD video without frame loss. For bulk data migration in data centers, the network needs to support on-demand, large-bandwidth allocation. In each of the aforementioned Zheng, et al. Expires August 22, 2021 [Page 4] Internet-Draft Framework and YANG of OTN Slices February 2021 vertical industry scenarios, the bandwidth shall be adjusted as required to ensure flexible and efficient network resource usage. 3. Framework for OTN slicing An OTN slice is a collection of OTN network resources that are used to establish a logically dedicated OTN virtual network over one or more OTN networks. For example, the bandwidth of an OTN slice is described in terms of the number/type of OTN time slots; the labels may be specified as OTN tributary slots and/or tributary ports to allow slice users to interconnect devices with matching specifications. The relationship between an OTN slice and an IETF network slice [I-D. teas-transport-network-slice-yang] is for further discussions. To support the configuration of OTN slices, an OTN slice controller (OTN-SC) can be deployed either outside or within the SDN controller. In the former case, the OTN-SC translates an OTN slice configuration request into a TE topology configuration or a set of TE tunnel configurations, and instantiate it by using the TE topology [RFC8795] or TE tunnel [I-D.ietf-teas-yang-te] interfaces at the MPI (MDSC-to- PNC Interface), as defined in the ACTN framework [RFC8453]. In the latter case, an Orchestrator or an end-to-end slice controller may request OTN slices directly through the OTN slicing interface provided by the OTN-SC. A higher-level OTN-SC may also designate the creation of OTN slices to a lower-level OTN-SC in a recursive manner. Figure 1 illustrates the OTN slicing control hierarchy and the positioning of the OTN slicing interfaces. Zheng, et al. Expires August 22, 2021 [Page 5] Internet-Draft Framework and YANG of OTN Slices February 2021 +--------------------+ | Provider's User | +--------|-----------+ |CMI +----------------------+---------------------------+ | Orchestrator / E2E Slice Controller | +-----------+------------------------------+-------+ |OTN-SC NBI | | | +-----------+---------+ OTN-SC NBI |OTN-SC NBI | OTN-SC +---------------+ | +-----------+---------+ | | |MPI | | +------------|-------------------------|----|--------+ | SDN | +-------+----+-------+| | Controller | | OTN-SC || | | +-------+------------+| | | |Internal API | |+-----------+-------------------------+------------+| || PNC/MDSC || |+-----------------------+--------------------------+| +------------------------|---------------------------+ |SBI +-----------+----------+ |OTN Physical Network | +----------------------+ Figure 1 - Positioning of OTN Slicing Interfaces A particular OTN network resource, such as a port or link, may be sliced in two modes: o Link-based slicing, where a link and its associated link termination points (LTPs) are dedicatedly allocated to a particular OTN network slice. o Tributary-slot based slicing, where multiple OTN network slices share the same link by allocating different OTN tributary slots in different granularities. Additionally, since OTN tributary slots are usually switched unconstrained at every node within an OTN network, it is unimportant to which exact tributary slot(s) an OTN slice is allocated, but rather mattered is the number and type of the tributary slots. Zheng, et al. Expires August 22, 2021 [Page 6] Internet-Draft Framework and YANG of OTN Slices February 2021 4. YANG Data Model for OTN Slicing Configuration 4.1. OTN Slicing YANG Model for MPI 4.1.1. MPI YANG Model Overview An SDN controller (PNC or MDSC) exposes to the OTN-SC set of available resources for OTN slicing in the form of an abstract TE topology. When the OTN-SC receives slice configuration from the NBI, it translates the configuration into a coloring scheme on the abstract TE topology, by marking corresponding link resources on the TE topology received from the SDN controller with a slice identifier and OTN-specific resource requirements, e.g. the number of ODU time slots. When the SDN controller receives the slice configuration, it shall create a new virtual TE link for each of the colored links to hold the reserved OTN time slots for time slot-based slicing. These resultant virtual links are then included in the TE topology advertisement to the OTN-SC. 4.1.2. MPI YANG Model Tree module: ietf-otn-slice augment /nw:networks/nw:network/nt:link/tet:te/tet:te-link- attributes: +--rw (otn-slice-granularity)? +--:(link) | +--rw slice-id? uint32 +--:(link-resource) +--rw slices* [slice-id] +--rw slice-id uint32 +--rw (technology)? | +--:(otn) | +--rw otn-ts-num? uint32 +--ro sliced-link-ref? -> ../../../../../nt:link/link-id Figure 2 - OTN network slicing tree diagram 4.1.3. MPI YANG Code file "ietf-otn-slice@2021-02-22.yang" module ietf-otn-slice { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-otn-slice"; Zheng, et al. Expires August 22, 2021 [Page 7] Internet-Draft Framework and YANG of OTN Slices February 2021 prefix "otnslice"; 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-topology { prefix "tet"; reference "RFC8795: YANG Data Model for Traffic Engineering (TE) Topologies"; } import ietf-otn-topology { prefix "otntopo"; reference "I-D.ietf-ccamp-otn-topo-yang: A YANG Data Model for Optical Transport Network Topology"; } organization "IETF CCAMP Working Group"; contact "WG Web: WG List: Editor: Haomian Zheng Editor: Italo Busi Editor: Aihua Guo Zheng, et al. Expires August 22, 2021 [Page 8] Internet-Draft Framework and YANG of OTN Slices February 2021 Editor: Victor Lopez "; description "This module defines a YANG data model to configure an OTN network slice realization. The model fully conforms to the Network Management Datastore Architecture (NMDA). Copyright (c) 2021 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 Simplified 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 "2021-02-22" { description "Initial Version"; reference "draft-zheng-ccamp-yang-otn-slicing-01: Framework and Data Model for OTN Network Slicing"; } /* * Groupings */ grouping otn-link-slice-profile { choice otn-slice-granularity { default link; case link { leaf slice-id { type uint32; description Zheng, et al. Expires August 22, 2021 [Page 9] Internet-Draft Framework and YANG of OTN Slices February 2021 "Slice identifier"; } } case link-resource { list slices { key slice-id; description "List of slices."; leaf slice-id { type uint32; description "Slice identifier"; } choice technology { case otn { leaf otn-ts-num { type uint32; description "Number of OTN tributary slots allocated for the slice."; } } } leaf sliced-link-ref { config false; type leafref { path "../../../../../nt:link/nt:link-id"; } description "Relative reference to virtual links generated from this TE link."; } } } } } /* * Augments */ Zheng, et al. Expires August 22, 2021 [Page 10] Internet-Draft Framework and YANG of OTN Slices February 2021 augment "/nw:networks/nw:network/nt:link/tet:te/" + "tet:te-link-attributes" { when "../../../nw:network-types/tet:te-topology/" + "otntopo:otn-topology" { description "Augmentation parameters apply only for networks with OTN topology type."; } description "Augment OTN TE link attributes with slicing profile."; uses otn-link-slice-profile; } } Figure 3 - OTN network slicing YANG model 4.2. OTN Slicing YANG Model for OTN-SC NBI TBD. 5. 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 optical 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. 6. Security Considerations 7. IANA Considerations Zheng, et al. Expires August 22, 2021 [Page 11] Internet-Draft Framework and YANG of OTN Slices February 2021 8. References 8.1. Normative References [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 . [RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, August 2020, . [I-D. teas-transport-network-slice-yang] Liu, X., Tantsura J., Bryskin I., Contreras L., Wu Q., Belotti S., and Rokui R., "Transport Network Slice YANG Data Model", draft-liu-teas- transport-network-slice-yang-01 (work in progress), July 2020. [I-D.ietf-teas-yang-te] Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin, "A YANG Data Model for Traffic Engineering Tunnels and Interfaces", draft-ietf-teas-yang-te-22 (work in progress), November 2019. 8.2. Informative References TBD Acknowledgments This document was prepared using 2-Word-v2.0.template.dot. Contributors' Addresses Henry Yu Huawei Technologies Canada Email: henry.yu@huawei.com Zheng, et al. Expires August 22, 2021 [Page 12] Internet-Draft Framework and YANG of OTN Slices February 2021 Authors' Addresses Haomian Zheng Huawei Technologies H1, Xiliu Beipo Village, Songshan Lake, Dongguan, China Email: zhenghaomian@huawei.com Italo Busi Huawei Technologies Email: italo.busi@huawei.com Aihua Guo Futurewei Technologies Email: aihuaguo.ietf@gmail.com Victor Lopez Telefonica I+D/GCTO Distrito Telefonica E-28050 Madrid, Spain Email: victor.lopezalvarez@telefonica.com Zheng, et al. Expires August 22, 2021 [Page 13]