< draft-contreras-nmrg-transport-slice-intent-03.txt		draft-contreras-nmrg-transport-slice-intent-04.txt >
	NMRG LM. Contreras		NMRG LM. Contreras
	Internet-Draft Telefonica		Internet-Draft Telefonica
	Intended status: Informational P. Demestichas		Intended status: Informational P. Demestichas
	Expires: January 27, 2021 WINGS		Expires: May 6, 2021 WINGS
	J. Tantsura		J. Tantsura
	Apstra, Inc.		Apstra, Inc.
	July 26, 2020		November 2, 2020
	Transport Slice Intent		IETF Network Slice Intent
	draft-contreras-nmrg-transport-slice-intent-03		draft-contreras-nmrg-transport-slice-intent-04
	Abstract		Abstract
	Slicing at the transport network is expected to be offered as part of		Slicing at the transport network is expected to be offered as part of
	end-to-end network slices, fostered by the introduction of new		end-to-end network slices, fostered by the introduction of new
	services such as 5G. This document explores the usage of intent		services such as 5G. This document explores the usage of intent
	technologies for requesting transport slices.		technologies for requesting IETF network slices.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
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	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
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	This Internet-Draft will expire on January 27, 2021.		This Internet-Draft will expire on May 6, 2021.
	Copyright Notice		Copyright Notice
	Copyright (c) 2020 IETF Trust and the persons identified as the		Copyright (c) 2020 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
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	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Transport slice intent . . . . . . . . . . . . . . . . . . . 3		2. IETF network slice intent . . . . . . . . . . . . . . . . . . 3
	3. Foundation of transport slice intents . . . . . . . . . . . . 3		3. Foundation of IETF network slice intents . . . . . . . . . . 3
	4. Mechanisms for translating transport slice intents . . . . . 4		4. Mechanisms for translating IETF network slice intents . . . . 4
	4.1. Translation approaches and interaction with the upper		4.1. Translation approaches and interaction with the upper
	systems . . . . . . . . . . . . . . . . . . . . . . . . . 4		systems . . . . . . . . . . . . . . . . . . . . . . . . . 4
	4.2. Intent-based system suite . . . . . . . . . . . . . . . . 5		4.2. Intent-based system suite . . . . . . . . . . . . . . . . 5
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 5		5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6		Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
	Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 6		Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
	skipping to change at page 2, line 37 ¶		skipping to change at page 2, line 37 ¶
	a customer with an apparent dedicated network built on top of logical		a customer with an apparent dedicated network built on top of logical
	(i.e. virtual) and/or physical functions and resources supported by a		(i.e. virtual) and/or physical functions and resources supported by a
	shared infrastructure, provided by one or more telecom operators.		shared infrastructure, provided by one or more telecom operators.
	The concept of network slicing has been largely fostered by the		The concept of network slicing has been largely fostered by the
	advent of 5G services that are expected to be deployed on top of		advent of 5G services that are expected to be deployed on top of
	different kind of slices, each built to support specific		different kind of slices, each built to support specific
	characteristics (extreme low latency, high bandwidth, etc).		characteristics (extreme low latency, high bandwidth, etc).
	As part of an end-to-end network slice it is expected to have a		As part of an end-to-end network slice it is expected to have a
	number of transport network slices providing the necessary		number of network slices at transport level (referred as IETF network
	connectivity to the rest of components of the end-to-end slice, e.g.,		slices) providing the necessary connectivity to the rest of
	mobile packet core slice.		components of the end-to-end slice, e.g., mobile packet core slice.
			For a definition of an IETF network slice refer to
			[I-D.nsdt-teas-ietf-network-slice-definition]. The following
			paragraph is directly taken from it: "An IETF Network Slice is a
			logical network topology connecting a number of endpoints with a set
			of shared or dedicated network resources, that are used to satisfy
			specific Service Level Objectives (SLOs)."
	For a definition of a transport slice refer to
	[I-D.nsdt-teas-transport-slice-definition]. The following paragraph
	is directly taken from it: "A transport slice is built based on a
	request from a higher operations system. The interface to higher
	operations systems should express the needed connectivity in a
	technology-agnostic way, and slice customers do not need to recognize
	concrete configurations based on the technologies (e.g being more
	declarative than imperative). The request to instantiate a transport
	slice is represented with some indicators such as SLO, and
	technologies are selected and managed accordingly."
	Intent is a high-level, declarative goal that operates at the level		Intent is a high-level, declarative goal that operates at the level
	of a network and services it provides, not individual devices. It is		of a network and services it provides, not individual devices. It is
	used to define outcomes and high-level operational goals.		used to define outcomes and high-level operational goals.
	In consequence, it seems very convenient to apply the intent-based		In consequence, it seems very convenient to apply the intent-based
	mechanisms for the provision of transport network slices, providing		mechanisms for the provision of IETF network slices, providing the
	the adequate level of abstraction towards the transport network		adequate level of abstraction towards the transport network control
	control and management planes.		and management planes.
	This document leverages current industry trends in the definition of		This document leverages current industry trends in the definition of
	end-to-end network slices. The final objective is to describe		end-to-end network slices. The final objective is to describe
	intents that can be used to flexibly declare the operational aspects		intents that can be used to flexibly declare the operational aspects
	and goals of a transport network slice, meaning that the customer		and goals of an IETF network slice, meaning that the customer could
	could declare what kind of transport slice is needed (the outcome)		declare what kind of IETF network slice is needed (the outcome) and
	and not how to achieve the goals of the transport slice.		not how to achieve the goals of the IETF network slice.
	2. Transport slice intent		2. IETF network slice intent
	As stated in [I-D.irtf-nmrg-ibn-concepts-definitions], "Intent is a		As stated in [I-D.irtf-nmrg-ibn-concepts-definitions], "Intent is a
	declaration of operational goals that a network should meet and		declaration of operational goals that a network should meet and
	outcomes that the network is supposed to deliver, without specifying		outcomes that the network is supposed to deliver, without specifying
	how to achieve them. Those goals and outcomes are defined in a		how to achieve them. Those goals and outcomes are defined in a
	manner that is purely declarative - they specify what to accomplish,		manner that is purely declarative - they specify what to accomplish,
	not how to achieve it."		not how to achieve it."
	When applied to transport networks, this implies that an intent for		When applied to transport networks, this implies that an intent for
	transport slices should provide the necessary abstraction with		IETF network slices should provide the necessary abstraction with
	respect to implementation details, including the final devices (or		respect to implementation details, including the final devices (or
	resources) involved, and be focused on the characteristics and		resources) involved, and be focused on the characteristics and
	performance expectations related to it.		performance expectations related to it.
	With that intent it can be expected that the intent based system can		With that intent it can be expected that the intent based system can
	fulfill and assure the requested transport network slice, triggering		fulfill and assure the requested IETF network slice, triggering
	initial configurations at the time of initial provisioning and		initial configurations at the time of initial provisioning and
	corrective actions during the transport slice lifetime.		corrective actions during the IETF network slice lifetime.
	3. Foundation of transport slice intents		3. Foundation of IETF network slice intents
	The industrial interest around 5G is accelerating network deployments		The industrial interest around 5G is accelerating network deployments
	and operational changes.		and operational changes.
	With this respect, the GSMA has been developing a universal blueprint		With this respect, the GSMA has been developing a universal blueprint
	that can be used by any vertical customer to request the deployment		that can be used by any vertical customer to request the deployment
	of a network slice instance (NSI) based on a specific set of service		of a network slice instance (NSI) based on a specific set of service
	requirements. Such a blueprint is a network slice descriptor called		requirements. Such a blueprint is a network slice descriptor called
	Generic Slice Template (GST) [GSMA]. The GST contains multiple		Generic Slice Template (GST) [GSMA]. The GST contains multiple
	attributes that can be used to characterize a network slice. A		attributes that can be used to characterize a network slice. A
	skipping to change at page 4, line 16 ¶		skipping to change at page 4, line 11 ¶
	Such templates refer to the end-to-end network slice, including the		Such templates refer to the end-to-end network slice, including the
	transport part. Despite the fact that some of the values would not		transport part. Despite the fact that some of the values would not
	have applicability for the transport network, others do. An analysis		have applicability for the transport network, others do. An analysis
	of the relevant attributes is performed in		of the relevant attributes is performed in
	[I-D.contreras-teas-slice-nbi].		[I-D.contreras-teas-slice-nbi].
	According to 3GPP propositions [TS28.541], an upper 3GPP Management		According to 3GPP propositions [TS28.541], an upper 3GPP Management
	System interacts with the transport network for establishing the		System interacts with the transport network for establishing the
	necessary slices at the transport level. Such interaction can be		necessary slices at the transport level. Such interaction can be
	expected to happen using the transport slice intent, described to an		expected to happen using the IETF network slice intent, described to
	intent-based system (IBS) in the transport network part. Then,		an intent-based system (IBS) in the transport network part. Then,
	according to the intent lifecycle in		according to the intent lifecycle in
	[I-D.irtf-nmrg-ibn-concepts-definitions], the IBS, after recognizing		[I-D.irtf-nmrg-ibn-concepts-definitions], the IBS, after recognizing
	the intent, will proceed to translate it in order to interact with a		the intent, will proceed to translate it in order to interact with a
	transport slice controller by using a NBI as proposed in		IETF network slice controller by using a NBI as proposed in
	[I-D.contreras-teas-slice-nbi].		[I-D.contreras-teas-slice-nbi].
	4. Mechanisms for translating transport slice intents		4. Mechanisms for translating IETF network slice intents
	This section describes approaches for implementing mechanisms to		This section describes approaches for implementing mechanisms to
	translate transport slice intents.		translate IETF network slice intents.
	4.1. Translation approaches and interaction with the upper systems		4.1. Translation approaches and interaction with the upper systems
	A suite of mechanisms will be required to allow instantiation of the		A suite of mechanisms will be required to allow instantiation of the
	user's intent into a transport slice. In order to be able to deliver		user's intent into a IETF network slice. In order to be able to
	an end2end Intent driven slice - a well defined set of context aware		deliver an end2end Intent driven slice - a well defined set of
	attributes that allow unambiguous instantiation of the intent should		context aware attributes that allow unambiguous instantiation of the
	be agreed upon. A combination of a structured set of		intent should be agreed upon. A combination of a structured set of
	attributes communicated between an IBN and an upper layer system with		attributes communicated between an IBN and an upper layer system with
	user input would allow an IBN to have intent modeled and reason about		user input would allow an IBN to have intent modeled and reason about
	its completeness/validity. Translation approaches and interaction		its completeness/validity. Translation approaches and interaction
	with the upper systems might benefit from Natural Language Processing		with the upper systems might benefit from Natural Language Processing
	(NLP) technics that are needed for enabling high level expression of		(NLP) technics that are needed for enabling high level expression of
	requirements found missing. The goal would be to identify and		requirements found missing. The goal would be to identify and
	classify the answers for as many fields as possible from the Generic		classify the answers for as many fields as possible from the Generic
	Slice Template (GST), based on the free text / speech provided by the		Slice Template (GST), based on the free text / speech provided by the
	user. As it is highly unlikely that the minimum set of fields to		user. As it is highly unlikely that the minimum set of fields to
	properly define a transport slice (geo-temporal characteristics,		properly define an IETF network slice (geo-temporal characteristics,
	performance characteristics, SLO and SLA properties) will be		performance characteristics, SLO and SLA properties) will be
	fulfilled in this first step, a follow up two-step approach might		fulfilled in this first step, a follow up two-step approach might
	need to be implemented.		need to be implemented.
	o The minimum missing fields from the GST have to be identified and		o The minimum missing fields from the GST have to be identified and
	appropriate questions have to be generated (e.g. based on a pool		appropriate questions have to be generated (e.g. based on a pool
	of available questions correlated with each field, or based on AI		of available questions correlated with each field, or based on AI
	approaches).		approaches).
	o An iterative interrogation phase will be initiated towards the		o An iterative interrogation phase will be initiated towards the
	skipping to change at page 5, line 42 ¶		skipping to change at page 5, line 37 ¶
	6. IANA Considerations		6. IANA Considerations
	This draft does not include any IANA considerations		This draft does not include any IANA considerations
	7. References		7. References
	[GSMA] "Generic Network Slice Template, version 3.0", NG.116 ,		[GSMA] "Generic Network Slice Template, version 3.0", NG.116 ,
	May 2020.		May 2020.
	[I-D.contreras-teas-slice-nbi]		[I-D.contreras-teas-slice-nbi]
	Contreras, L., Homma, S., and J. Ordonez-Lucena,		Contreras, L., Homma, S., and J. Ordonez-Lucena, "IETF
	"Considerations for defining a Transport Slice NBI",		Network Slice use cases and attributes for Northbound
	draft-contreras-teas-slice-nbi-01 (work in progress),		Interface of controller", draft-contreras-teas-slice-
	March 2020.		nbi-03 (work in progress), October 2020.
	[I-D.irtf-nmrg-ibn-concepts-definitions]		[I-D.irtf-nmrg-ibn-concepts-definitions]
	Clemm, A., Ciavaglia, L., Granville, L., and J. Tantsura,		Clemm, A., Ciavaglia, L., Granville, L., and J. Tantsura,
	"Intent-Based Networking - Concepts and Definitions",		"Intent-Based Networking - Concepts and Definitions",
	draft-irtf-nmrg-ibn-concepts-definitions-01 (work in		draft-irtf-nmrg-ibn-concepts-definitions-02 (work in
	progress), March 2020.		progress), September 2020.
	[I-D.nsdt-teas-transport-slice-definition]		[I-D.nsdt-teas-ietf-network-slice-definition]
	Rokui, R., Homma, S., Makhijani, K., and L. Contreras,		Rokui, R., Homma, S., Makhijani, K., Contreras, L., and J.
	"IETF Definition of Transport Slice", draft-nsdt-teas-		Tantsura, "Definition of IETF Network Slices", draft-nsdt-
	transport-slice-definition-02 (work in progress), April		teas-ietf-network-slice-definition-00 (work in progress),
	2020.		October 2020.
	[TS28.541]		[TS28.541]
	"TS 28.541 Management and orchestration; 5G Network		"TS 28.541 Management and orchestration; 5G Network
	Resource Model (NRM); Stage 2 and stage 3 (Release 16)		Resource Model (NRM); Stage 2 and stage 3 (Release 16)
	V16.2.0.", 3GPP TS 28.541 V16.2.0 , September 2019.		V16.2.0.", 3GPP TS 28.541 V16.2.0 , September 2019.
	Acknowledgments		Acknowledgments
	This work has been partly funded by the European Commission through		This work has been partly funded by the European Commission through
	the H2020 project 5G-EVE (Grant Agreement no. 815074).		the H2020 project 5G-EVE (Grant Agreement no. 815074).
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