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Contreras 3 Internet-Draft Telefonica 4 Intended status: Informational P. Demestichas 5 Expires: September 10, 2020 WINGS 6 March 9, 2020 8 Transport Slice Intent 9 draft-contreras-nmrg-transport-slice-intent-00 11 Abstract 13 Slicing at the transport network is expected to be offered as part of 14 end-to-end network slices, fostered by the introducion of new 15 services such as 5G. This document explores the usage of intent 16 machanisms for requesting transport slices. 18 Status of This Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at https://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on September 10, 2020. 35 Copyright Notice 37 Copyright (c) 2020 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (https://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 53 2. Transport slice intent . . . . . . . . . . . . . . . . . . . 3 54 3. Foundation of transport slice intents . . . . . . . . . . . . 3 55 4. Mechanisms for translating transport slice intents . . . . . 4 56 4.1. Translation approaches and interaction with the upper 57 systems . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 4.2. Intent-based system suite . . . . . . . . . . . . . . . . 4 59 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 60 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 61 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 62 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 6 64 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 66 1. Introduction 68 Network slicing is emerging as the future model for service offering 69 in telecom operator networks. Conceptually, network slicing provides 70 a customer with an apparent dedicated network built on top of logical 71 (i.e. virtual) and/or physical functions and resources supported by a 72 shared infrastructure, the one from the telecom operator. 74 The concept of network slicing has been largely fostered by the 75 advent of 5G services which are expected to be deployed on top of 76 different kind of slices, each built to support specific 77 characteristics (extreme low latency, high bandwidth, etc). 79 As part of an end-to-end network slice it is expected to have a 80 number of transport network slices providing the necessary 81 connectivity to the rest of components of the end-to-end slice, e.g., 82 mobile packet core slice. 84 For a definition of transport slice refer to 85 [I-D.nsdt-teas-transport-slice-definition]. The following paragraph 86 is directly taken from it: "A transport slice is built based on a 87 request from a higher operations system. The interface to higher 88 operations systems should express the needed connectivity in a 89 technology-agnostic way, and slice customers do not need to recognize 90 concrete configurations based on the technologies (e.g being more 91 declarative than imperative). The request to instantiate a transport 92 slice is represented with some indicators such as SLO, and 93 technologies are selected and managed accordingly." 95 In consequence, it seems very convenient to apply the intent-based 96 mechanisms for the provision of transport network slices, providing 97 the adequate level of abstraction towards the transport network 98 control and management artifacts. 100 This document works on that direction by leveraging on current 101 industry trends in the definition of end-to-end network slices. The 102 final objective is to describe intents that can flexibly declare the 103 operational aspects and goals of a transport network slice, meaning 104 that the customer could declare what kind of transport slice is 105 needed and not how to achieve the goals of the transport slice. 107 2. Transport slice intent 109 As stated in [I-D.irtf-nmrg-ibn-concepts-definitions], "Intent is a 110 higher-level declarative policy that operates at the level of a 111 network and services it provides, not individual devices. It is used 112 to define outcomes and high-level operational goals, without the need 113 to enumerate specific events, conditions, and actions". 115 When applied to transport networks, this implies that an intent for 116 transport slices should provide the necessary abstraction with 117 respect to implementation details, including the final devices (or 118 resources) involved, and be focused on the characteristics and 119 performance expectations related to it. 121 With that intent it can be expected that the intent-based system can 122 fulfill and assure the requested transport network slice, triggering 123 initial configurations at the time of initial provisioning and 124 corrective actions during the transport slice lifetime. 126 3. Foundation of transport slice intents 128 The industrial interest around 5G is accelerating network deployments 129 and operational changes. 131 With this respect, the GSMA is developing a universal blueprint that 132 can be used by any vertical customer to order the deployment of a 133 network slice instance (NSI) based on a specific set of service 134 requirements. Such a blueprint is a network slice descriptor called 135 Generic Slice Template (GST) [GSMA]. The GST contains multiple 136 attributes that can be used to characterize a network slice. A 137 particular template filled with values generates a specific Network 138 Slice Type(NEST). 140 Such templates refer to the end-to-end network slice, including the 141 transport part. Despite some of the values could not have 142 applicability for the transport network, others do. An analysis of 143 relevant attributes is performed in [I-D.contreras-teas-slice-nbi]. 145 According to 3GPP propositions [TS28.541] an upper 3GPP Management 146 System interacts with the transport network for establishing the 147 necessary slices at the transport level. Such interaction can be 148 expected to happen using the transport slice intents here described 149 to an intent-based system (IBS) in the transport network part. Then, 150 according to the intent lifecycle in 151 [I-D.irtf-nmrg-ibn-concepts-definitions], the IBS, after recognizing 152 the intent, will proceed to translate it in order to interact with a 153 transport slice controller by using a NBI as proposed in 154 [I-D.contreras-teas-slice-nbi]. 156 4. Mechanisms for translating transport slice intents 158 This section describes approaches for implementing mechanisms able to 159 translate transport slice intents. 161 4.1. Translation approaches and interaction with the upper systems 163 A suite of mechanisms will be required and can be used for the 164 translation of the user's intent into a transport slice. NLP 165 (Natural Language Processing) approaches are needed for enabling the 166 expression of requirements in high level terms, and for conducting a 167 first analysis towards lower-level network requirements/resources. 168 The goal would be to identify and classify the answers for as many 169 fields as possible from the Generic Slice Template (GST), based on 170 the free text / speech provided by the user. As it is highly 171 unlikely that the minimum set of fields to properly define a 172 transport slice (geo-temporal characteristics, performance 173 characteristics, SLA properties) will be fulfilled in this first 174 step, a follow up two-step approach will have to be implemented. 176 o The minimum missing fields from the GST have to be identified and 177 appropriate questions have to be generated (e.g. based on a pool 178 of available questions corelated with each field, or based on AI 179 approaches) 181 o An iterative interrogation phase will be initiated towards the 182 user using the previously generated questions, until the user 183 provides all the missing information 185 Interaction with the user and higher-up systems can potentially be 186 further improved by utilizing Machine learning techniques. 188 4.2. Intent-based system suite 190 A combination of deterministic or stochastic computation approaches 191 will be needed, in order to consolidate on the set of devices, 192 technologies and resources to be used. Deterministic approaches will 193 rely on mathematical models and respective algorithms. Stochastic 194 approaches will rely on technologies like machine learning. Their 195 goal will be to learn from experience, so as to optimize future 196 decisions from the viewpoint of speed and reliability. The target of 197 learning will be related to the service behavior and to the 198 anticipated network status in the area and time period of the service 199 provision. 201 5. Security Considerations 203 To be done. 205 6. IANA Considerations 207 This draft does not include any IANA considerations 209 7. References 211 [GSMA] "Generic Network Slice Template, version 2.0", NG.116 , 212 October 2019. 214 [I-D.contreras-teas-slice-nbi] 215 Contreras, L., Homma, S., and J. Ordonez-Lucena, 216 "Considerations for defining a Transport Slice NBI", 217 draft-contreras-teas-slice-nbi-00 (work in progress), 218 November 2019. 220 [I-D.irtf-nmrg-ibn-concepts-definitions] 221 Clemm, A., Ciavaglia, L., Granville, L., and J. Tantsura, 222 "Intent-Based Networking - Concepts and Definitions", 223 draft-irtf-nmrg-ibn-concepts-definitions-00 (work in 224 progress), December 2019. 226 [I-D.nsdt-teas-transport-slice-definition] 227 Rokui, R., Homma, S., and K. Makhijani, "IETF Definition 228 of Transport Slice", draft-nsdt-teas-transport-slice- 229 definition-00 (work in progress), November 2019. 231 [TS28.541] 232 "TS 28.541 Management and orchestration; 5G Network 233 Resource Model (NRM); Stage 2 and stage 3 (Release 16) 234 V16.2.0.", 3GPP TS 28.541 V16.2.0 , September 2019. 236 Acknowledgments 238 This work has been partly funded by the European Commission through 239 the H2020 project 5G-EVE (Grant Agreement no. 815074). 241 Contributors 243 Kostas Tsagkaris, Kostas Trichias, Vassilis Foteinos, and Thanasis 244 Gkiolias (all from WINGS ICT Solutions) have also contributed to this 245 work. 247 Authors' Addresses 249 Luis M. Contreras 250 Telefonica 251 Ronda de la Comunicacion, s/n 252 Sur-3 building, 3rd floor 253 Madrid 28050 254 Spain 256 Email: luismiguel.contrerasmurillo@telefonica.com 257 URI: http://lmcontreras.com/ 259 Panagiotis Demestichas 260 WINGS ICT Solutions 261 Greece 263 Email: pdemest@wings-ict-solutions.eu