< draft-nsdt-teas-ietf-network-slice-definition-01.txt		draft-nsdt-teas-ietf-network-slice-definition-02.txt >
	teas R. Rokui		teas R. Rokui
	Internet-Draft Nokia		Internet-Draft Nokia
	Intended status: Informational S. Homma		Intended status: Informational S. Homma
	Expires: May 6, 2021 NTT		Expires: June 14, 2021 NTT
	K. Makhijani		K. Makhijani
	Futurewei		Futurewei
	LM. Contreras		LM. Contreras
	Telefonica		Telefonica
	J. Tantsura		J. Tantsura
	Apstra, Inc.		Apstra, Inc.
	November 2, 2020		December 11, 2020
	Definition of IETF Network Slices		Definition of IETF Network Slices
	draft-nsdt-teas-ietf-network-slice-definition-01		draft-nsdt-teas-ietf-network-slice-definition-02
	Abstract		Abstract
	This document provides a definition of the term "IETF Network Slice"		This document provides a definition of the term "IETF Network Slice"
	for use within the IETF and specifically as a reference for other		for use within the IETF and specifically as a reference for other
	IETF documents that describe or use aspects of network slices.		IETF documents that describe or use aspects of network slices.
	The document also describes the characteristics of an IETF network		The document also describes the characteristics of an IETF network
	slice, related terms and their meanings, and explains how IETF		slice, related terms and their meanings, and explains how IETF
	network slices can be used in combination with end-to-end network		network slices can be used in combination with end-to-end network
	skipping to change at page 1, line 44 ¶		skipping to change at page 1, line 44 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	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-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on May 6, 2021.		This Internet-Draft will expire on June 14, 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.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Rationale . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 3
	2. Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 4
	3. Definition and Scope of IETF Network Slice . . . . . . . . . 4		3. Definition and Scope of IETF Network Slice . . . . . . . . . 4
	4. IETF Network Slice System Characteristics . . . . . . . . . . 5		4. IETF Network Slice System Characteristics . . . . . . . . . . 4
	4.1. Objectives for IETF Network Slices . . . . . . . . . . . 5		4.1. Objectives for IETF Network Slices . . . . . . . . . . . 5
	4.1.1. Service Level Objectives . . . . . . . . . . . . . . 5		4.1.1. Service Level Objectives . . . . . . . . . . . . . . 5
	4.1.2. Minimal Set of SLOs . . . . . . . . . . . . . . . . . 6		4.1.2. Minimal Set of SLOs . . . . . . . . . . . . . . . . . 5
	4.1.3. Other Objectives . . . . . . . . . . . . . . . . . . 7		4.1.3. Other Objectives . . . . . . . . . . . . . . . . . . 7
	4.2. IETF Network Slice Endpoints . . . . . . . . . . . . . . 7		4.2. IETF Network Slice Endpoints . . . . . . . . . . . . . . 7
	4.2.1. IETF Network Slice Connectivity Types . . . . . . . . 9		4.2.1. IETF Network Slice Connectivity Types . . . . . . . . 9
	4.3. IETF Network Slice Composition . . . . . . . . . . . . . 9		4.3. IETF Network Slice Composition . . . . . . . . . . . . . 9
	5. IETF Network Slice Structure . . . . . . . . . . . . . . . . 10		5. IETF Network Slice Structure . . . . . . . . . . . . . . . . 10
	6. IETF Network Slice Stakeholders . . . . . . . . . . . . . . . 11		6. IETF Network Slice Stakeholders . . . . . . . . . . . . . . . 11
	7. IETF Network Slice Controller Interfaces . . . . . . . . . . 12		7. IETF Network Slice Controller Interfaces . . . . . . . . . . 12
	8. Realizing IETF Network Slice . . . . . . . . . . . . . . . . 12		8. Realizing IETF Network Slice . . . . . . . . . . . . . . . . 12
	9. Isolation in IETF Network Slices . . . . . . . . . . . . . . 13		9. Isolation in IETF Network Slices . . . . . . . . . . . . . . 13
	9.1. Isolation as a Service Requirement . . . . . . . . . . . 13		9.1. Isolation as a Service Requirement . . . . . . . . . . . 13
	9.2. Isolation in IETF Network Slice Realization . . . . . . . 14		9.2. Isolation in IETF Network Slice Realization . . . . . . . 13
	9.3. Relationship with Isolation in 5G Network Slice . . . . . 14
	10. Security Considerations . . . . . . . . . . . . . . . . . . . 14		10. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15		11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
	12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 15		12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 15
	13. Informative References . . . . . . . . . . . . . . . . . . . 15		13. Informative References . . . . . . . . . . . . . . . . . . . 15
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	1. Introduction		1. Introduction
	A number of use cases benefit from network connections that along		A number of use cases benefit from network connections that along
	with the connectivity provide assurance of meeting a specific set of		with the connectivity provide assurance of meeting a specific set of
	objectives wrt network resources use. In this document, as detailed		objectives wrt network resources use. In this document, as detailed
	in the subsequent sections, we refer to this connectivity and		in the subsequent sections, we refer to this connectivity and
	skipping to change at page 3, line 18 ¶		skipping to change at page 3, line 17 ¶
	o 5G services (e.g. eMBB, URLLC, mMTC)(See [TS.23.501-3GPP])		o 5G services (e.g. eMBB, URLLC, mMTC)(See [TS.23.501-3GPP])
	o Network wholesale services		o Network wholesale services
	o Network infrastructure sharing among operators		o Network infrastructure sharing among operators
	o NFV connectivity and Data Center Interconnect		o NFV connectivity and Data Center Interconnect
	The use cases are further described in [I-D.nsdt-teas-ns-framework].		The use cases are further described in [I-D.nsdt-teas-ns-framework].
	This document defines the concept of IETF Network Slices that provide		This document defines the concept of IETF network slices that provide
	connectivity coupled with a set of specific commitments of network		connectivity coupled with a set of specific commitments of network
	resources between a number of endpoints over a shared network		resources between a number of endpoints over a shared network
	infrastructure. Since the term network slice is rather generic, the		infrastructure. Since the term network slice is rather generic, the
	qualifying term 'IETF' is used in this document to limit the scope of		qualifying term 'IETF' is used in this document to limit the scope of
	network slice to network technologies described and standardized by		network slice to network technologies described and standardized by
	the IETF.		the IETF.
	1.1. Rationale		IETF network slices are created and managed within the scope of one
	IETF Network Slices are created and managed within the scope of one
	or more network technologies (e.g., IP, MPLS, optical). They are		or more network technologies (e.g., IP, MPLS, optical). They are
	intended to enable a diverse set of applications that have different		intended to enable a diverse set of applications that have different
	requirements to coexist on the same network infrastructure.		requirements to coexist on the same network infrastructure. A
			request for an IETF network slice is technology-agnostic so as to
	An IETF Network Slice is a well-defined structure of connectivity		allow a consumer to describe their network connectivity objectives in
	requirements and associated network behaviors. IETF Network Slices		a common format, independent of the underlying technologies used.
	are defined such that they are independent of the underlying
	infrastructure connectivity and technologies used. This is to allow
	an IETF Network Slice consumer to describe their network connectivity
	and relevant objectives in a common format, independent of the
	underlying technologies used.
	IETF Network Slices may be combined hierarchically, so that a network
	slice may itself be sliced. They may also be combined sequentially
	so that various different networks can each be sliced and the network
	slices placed into a sequence to provide an end-to-end service. This
	form of sequential combination is utilized in some services such as
	in 3GPP's 5G network [TS.23.501-3GPP].
	2. Terms and Abbreviations		2. Terms and Abbreviations
	The terms and abbreviations used in this document are listed below.		The terms and abbreviations used in this document are listed below.
	o NS: Network Slice		o NS: Network Slice
	o NSC: Network Slice Controller		o NSC: Network Slice Controller
	o NBI: NorthBound Interface		o NBI: NorthBound Interface
	skipping to change at page 4, line 22 ¶		skipping to change at page 4, line 4 ¶
	o NBI: NorthBound Interface		o NBI: NorthBound Interface
	o SBI: SouthBound Interface		o SBI: SouthBound Interface
	o SLI: Service Level Indicator		o SLI: Service Level Indicator
	o SLO: Service Level Objective		o SLO: Service Level Objective
	o SLA: Service Level Agreement		o SLA: Service Level Agreement
	The above terminology is defined in greater details in the remainder		The above terminology is defined in greater details in the remainder
	of this document.		of this document.
	3. Definition and Scope of IETF Network Slice		3. Definition and Scope of IETF Network Slice
	The definition of a network slice in IETF context is as follows:		The definition of a network slice in IETF context is as follows:
	An IETF Network Slice is a logical network topology connecting a		An IETF network slice is a logical network topology connecting a
	number of endpoints with a set of shared or dedicated network		number of endpoints using a set of shared or dedicated network
	resources, that are used to satisfy specific Service Level Objectives		resources that are used to satisfy specific Service Level Objectives
	(SLOs).		(SLOs).
	IETF Network Slice specification is technology-agnostic, and the		An IETF network slice combines the connectivity resource requirements
	means for IETF network slice realization can be chosen depending on		and associated network behaviors such as bandwidth, latency, jitter,
	several factors such as: service requirements, specifications or		and network functions with other resource behaviors such as compute
	capabilities of underlying infrastructure. The structure and		and storage availability. IETF network slices are independent of the
	different characteristics of IETF Network Slices are described in the		underlying infrastructure connectivity and technologies used. This
	following sections.		is to allow an IETF network slice consumer to describe their network
			connectivity and relevant objectives in a common format, independent
			of the underlying technologies used.
			IETF network slices may be combined hierarchically, so that a network
			slice may itself be sliced. They may also be combined sequentially
			so that various different networks can each be sliced and the network
			slices placed into a sequence to provide an end-to-end service. This
			form of sequential combination is utilized in some services such as
			in 3GPP's 5G network [TS.23.501-3GPP].
			An IETF network slice is technology-agnostic, and the means for IETF
			network slice realization can be chosen depending on several factors
			such as: service requirements, specifications or capabilities of
			underlying infrastructure. The structure and different
			characteristics of IETF network slices are described in the following
			sections.
	Term "Slice" refers to a set of characteristics and behaviours that		Term "Slice" refers to a set of characteristics and behaviours that
	separate one type of user-traffic from another. IETF Network Slice		separate one type of user-traffic from another. IETF network slice
	assumes that an underlying network is capable of changing the		assumes that an underlying network is capable of changing the
	configurations of the network devices on demand, through in-band		configurations of the network devices on demand, through in-band
	signaling or via controller(s) and fulfilling all or some of SLOs to		signaling or via controller(s) and fulfilling all or some of SLOs to
	all of the traffic in the slice or to specific flows.		all of the traffic in the slice or to specific flows.
	4. IETF Network Slice System Characteristics		4. IETF Network Slice System Characteristics
	The following subsections describe the characteristics of IETF		The following subsections describe the characteristics of IETF
	network slices.		network slices.
	4.1. Objectives for IETF Network Slices		4.1. Objectives for IETF Network Slices
	An IETF Network Slice is defined in terms of several quantifiable		An IETF network slice is defined in terms of several quantifiable
	characteristics or service level objectives (SLOs). SLOs along with		characteristics or service level objectives (SLOs). SLOs along with
	terms Service Level Indicator (SLI) and Service Level Agreement (SLA)		terms Service Level Indicator (SLI) and Service Level Agreement (SLA)
	are used to define the performance of a service at different levels.		are used to define the performance of a service at different levels.
	A Service Level Indicator (SLI) is a quantifiable measure of an		A Service Level Indicator (SLI) is a quantifiable measure of an
	aspect of the performance of a network. For example, it may be a		aspect of the performance of a network. For example, it may be a
	measure of throughput in bits per second, or it may be a measure of		measure of throughput in bits per second, or it may be a measure of
	latency in milliseconds.		latency in milliseconds.
	A Service Level Objective (SLO) is a target value or range for the		A Service Level Objective (SLO) is a target value or range for the
	measurements returned by observation of an SLI. For example, an SLO		measurements returned by observation of an SLI. For example, an SLO
	may be expressed as "SLI <= target", or "lower bound <= SLI <= upper		may be expressed as "SLI <= target", or "lower bound <= SLI <= upper
	bound". A network slice is expressed in terms of the set of SLOs		bound". A network slice is expressed in terms of the set of SLOs
	that are to be delivered for the different connections between		that are to be delivered for the different connections between
	endpoints.		endpoints.
	A Service Level Agreement (SLA) is an explicit or implicit contract		A Service Level Agreement (SLA) is an explicit or implicit contract
	between the consumer of an IETF Network Slice and the provider of the		between the consumer of an IETF network slice and the provider of the
	slice. The SLA is expressed in terms of a set of SLOs and may		slice. The SLA is expressed in terms of a set of SLOs and may
	include commercial terms as well as the consequences of missing/		include commercial terms as well as the consequences of missing/
	violating the SLOs they contain.		violating the SLOs they contain.
	Additional descriptions of IETF network slice attributes is covered		Additional descriptions of IETF network slice attributes is covered
	in [I-D.contreras-teas-slice-nbi].		in [I-D.contreras-teas-slice-nbi].
	4.1.1. Service Level Objectives		4.1.1. Service Level Objectives
	SLOs define a set of network attributes and characteristics that		SLOs define a set of network attributes and characteristics that
	skipping to change at page 6, line 19 ¶		skipping to change at page 6, line 14 ¶
	SLOs can be categorized in to 'Directly Measurable Objectives' or		SLOs can be categorized in to 'Directly Measurable Objectives' or
	'Indirectly Measurable Objectives'. Objectives such as guaranteed		'Indirectly Measurable Objectives'. Objectives such as guaranteed
	minimum bandwidth, guaranteed maximum latency, maximum permissible		minimum bandwidth, guaranteed maximum latency, maximum permissible
	delay variation, maximum permissible packet loss rate, and		delay variation, maximum permissible packet loss rate, and
	availability are 'Directly Measurable Objectives'. While 'Indirectly		availability are 'Directly Measurable Objectives'. While 'Indirectly
	Measurable Objectives' include security, geographical restrictions,		Measurable Objectives' include security, geographical restrictions,
	maximum occupancy level objectives. The later standard might define		maximum occupancy level objectives. The later standard might define
	other SLOs as needed.		other SLOs as needed.
	Editor's Note TODO: Minimal set describes most commonly used		Editor's Note TODO: replace Minimal set to most commonly used
	objectives to describe network behavior. Other directly or		objectives to describe network behavior. Other directly or
	indirectly measurable objectives may be requested by that customer of		indirectly measurable objectives may be requested by that consumer of
	an IETF network slice.		an IETF network slice.
	The definition of these objectives are as follows:		The definition of these objectives are as follows:
	Guaranteed Minimum Bandwidth		Guaranteed Minimum Bandwidth
	Minimum guaranteed bandwidth between two endpoints at any time.		Minimum guaranteed bandwidth between two endpoints at any time.
	The bandwidth is measured in data rate units of bits per second		The bandwidth is measured in data rate units of bits per second
	and is measured unidirectionally.		and is measured unidirectionally.
	skipping to change at page 7, line 4 ¶		skipping to change at page 6, line 48 ¶
	difference in the one-way delay between sequential packets in a		difference in the one-way delay between sequential packets in a
	flow. This SLO sets a maximum value PDV for packets between		flow. This SLO sets a maximum value PDV for packets between
	two endpoints.		two endpoints.
	Maximum permissible packet loss rate		Maximum permissible packet loss rate
	The ratio of packets dropped to packets transmitted between two		The ratio of packets dropped to packets transmitted between two
	endpoints over a period of time. See [RFC7680]		endpoints over a period of time. See [RFC7680]
	Availability		Availability
	The ratio of uptime to the sum of uptime and downtime, where		The ratio of uptime to the sum of uptime and downtime, where
	uptime is the time the IETF network slice is available in		uptime is the time the IETF network slice is available in
	accordance with the SLOs associated with it.		accordance with the SLOs associated with it.
	Security		Security
	An IETF Network Slice consumer may request that the network		An IETF network slice consumer may request that the network
	applies encryption or other security techniques to traffic		applies encryption or other security techniques to traffic
	flowing between endpoints.		flowing between endpoints.
	Note that the use of security or the violation of this SLO is		Note that the use of security or the violation of this SLO is
	not directly observable by the IETF Network Slice consumer and		not directly observable by the IETF network slice consumer and
	cannot be measured as a quantifiable metric.		cannot be measured as a quantifiable metric.
	Also note that the objective may include request for encryption		Also note that the objective may include request for encryption
	(e.g., [RFC4303]) between the two endpoints explicitly to meet		(e.g., [RFC4303]) between the two endpoints explicitly to meet
	architecture recommendations as in [TS33.210] or for compliance		architecture recommendations as in [TS33.210] or for compliance
	with [HIPAA] and/or [PCI].		with [HIPAA] and/or [PCI].
	Editor's Note: Please see more discussion on security in		Editor's Note: Please see more discussion on security in
	Section 10.		Section 10.
	4.1.3. Other Objectives		4.1.3. Other Objectives
	Additional SLOs may be defined to provide additional description of		Additional SLOs may be defined to provide additional description of
	the IETF network slice that a consumer requests.		the IETF network slice that a consumer requests.
	If the IETF Network Slice consumer service is traffic aware, other		If the IETF network slice consumer service is traffic aware, other
	traffic specific characteristics may be valuable including MTU,		traffic specific characteristics may be valuable including MTU,
	traffic-type (e.g., IPv4, IPv6, Ethernet or unstructured), or a		traffic-type (e.g., IPv4, IPv6, Ethernet or unstructured), or a
	higher-level behavior to process traffic according to user-		higher-level behavior to process traffic according to user-
	application (which may be realized using network functions).		application (which may be realized using network functions).
	Maximal occupancy for an IETF network slice should be provided.		Maximal occupancy for an IETF network slice should be provided.
	Since it carries traffic for multiple flows between the two		Since it carries traffic for multiple flows between the two
	endpoints, the objectives should also say if they are for the entire		endpoints, the objectives should also say if they are for the entire
	connection, group of flows or on per flow basis. Maximal occupancy		connection, group of flows or on per flow basis. Maximal occupancy
	should specify the scale of the flows (i.e. maximum number of flows		should specify the scale of the flows (i.e. maximum number of flows
	skipping to change at page 8, line 8 ¶		skipping to change at page 8, line 5 ¶
	4.2. IETF Network Slice Endpoints		4.2. IETF Network Slice Endpoints
	As noted in Section 3, an IETF network slice describes connectivity		As noted in Section 3, an IETF network slice describes connectivity
	between endpoints across the underlying network. This connectivity		between endpoints across the underlying network. This connectivity
	may be be point-to-point, point-to-multipoint (P2MP), multipoint-to-		may be be point-to-point, point-to-multipoint (P2MP), multipoint-to-
	point, or multipoint-to-multipoint.		point, or multipoint-to-multipoint.
	The characteristics of IETF network slice endpoints (NSEs) are as		The characteristics of IETF network slice endpoints (NSEs) are as
	follows.		follows.
	o They are conceptual points of connection of a customer network,		o They are conceptual points of connection of a consumer network,
	network function, device, or application to the IETF network		network function, device, or application to the IETF network
	slice. This might include routers, switches, firewalls, WAN,		slice. This might include routers, switches, firewalls, WAN,
	4G/5G RAN nodes, 4G/5G Core nodes, application acceleration, Deep		4G/5G RAN nodes, 4G/5G Core nodes, application acceleration, Deep
	Packet Inspection (DPI), server load balancers, NAT44 [RFC3022],		Packet Inspection (DPI), server load balancers, NAT44 [RFC3022],
	NAT64 [RFC6146], HTTP header enrichment functions, and TCP		NAT64 [RFC6146], HTTP header enrichment functions, and TCP
	optimizers.		optimizers.
	o They are identified in a request provided by the consumer of an		o They are identified in a request provided by the consumer of an
	IETF Network Slice when the IETF Network Slice is requested.		IETF network slice when the IETF network slice is requested.
	o An NSE is identified a unique identifier and/or a unique name and		o An NSE is identified a unique identifier and/or a unique name and
	other data. A non-exhaustive list of other data includes IPv4 or		other data. A non-exhaustive list of other data includes IPv4 or
	IPv6 address, VLAN tag, port number, connectivity type (P2P, P2MP,		IPv6 address, VLAN tag, port number, connectivity type (P2P, P2MP,
	MP2MP).		MP2MP).
	Note that the NSE is different from access points (AP) defined in		Note that the NSE is different from access points (AP) defined in
	[RFC8453] as an AP is a logical identifier to identify the shared		[RFC8453] as an AP is a logical identifier to identify the shared
	link between the customer and the operator where as NSE is an		link between the consumer and the operator where as NSE is an
	identifier of an endpoint. Also NSE is different from TE Link		identifier of an endpoint. Also NSE is different from TE Link
	Termination Point (LTP) defined in [I-D.ietf-teas-yang-te-topo] as it		Termination Point (LTP) defined in [I-D.ietf-teas-yang-te-topo] as it
	is a conceptual point of connection of a TE node to one of the TE		is a conceptual point of connection of a TE node to one of the TE
	links on a TE node.		links on a TE node.
	The NSE is similar to the Termination Point (TP) defined in [RFC8345]		The NSE is similar to the Termination Point (TP) defined in [RFC8345]
	and can contain more attributes. NSE could be modeled by augmenting		and can contain more attributes. NSE could be modeled by augmenting
	the TP model.		the TP model.
	There is another type of the endpoints called "IETF Network Slice		There is another type of the endpoints called "IETF Network Slice
	Realization Endpoints (NSREs)". These endpoints are allocated and		Realization Endpoints (NSREs)". These endpoints are allocated and
	assigned by the network controller during the realization of an IETF		assigned by the network controller during the realization of an IETF
	Network Slice and are technology-specific, i.e. they depend on the		network slice and are technology-specific, i.e. they depend on the
	network technology used during the IETF Network Slice realization.		network technology used during the IETF network slice realization.
	The identification of NSREs forms part of the realization of the IETF		The identification of NSREs forms part of the realization of the IETF
	Network Slice and is implementation and deployment specific.		network slice and is implementation and deployment specific.
	Figure 1 shows an example of an IETF Network Slice and its		Figure 1 shows an example of an IETF network slice and its
	realization between multiple NSEs and NSREs.		realization between multiple NSEs and NSREs.
	(-------------------)		(-------------------)
	( IETF scoped Network )		( IETF scoped Network )
	DAN1 ( ) DAN2		DAN1 ( ) DAN2
	-------- NSRE1 -------- -------- NSRE2 --------		-------- NSRE1 -------- -------- NSRE2 --------
	| o |-------o| A | | B |o--------| o |		| o |-------o| A | | B |o--------| o |
	| NSE1| -------- -------- | NSE2 |		| NSE1| -------- -------- | NSE2 |
	-------- | ( ) | --------		-------- | ( ) | --------
	| | ( ) | |		| | ( ) | |
	skipping to change at page 9, line 37 ¶		skipping to change at page 9, line 37 ¶
	4.2.1. IETF Network Slice Connectivity Types		4.2.1. IETF Network Slice Connectivity Types
	The IETF Network Slice connection types can be point to point (P2P),		The IETF Network Slice connection types can be point to point (P2P),
	point to multipoint (P2MP), multi-point to point (MP2P), or multi-		point to multipoint (P2MP), multi-point to point (MP2P), or multi-
	point to multi-point (MP2MP). They will requested by the higher		point to multi-point (MP2MP). They will requested by the higher
	level operation system.		level operation system.
	4.3. IETF Network Slice Composition		4.3. IETF Network Slice Composition
	Operationally, an IETF Network Slice maybe decomposed in two or more		Operationally, an IETF network slice maybe decomposed in two or more
	IETF Network Slices as specified below. Decomposed network slices		IETF network slices as specified below. Decomposed network slices
	are then independently realized and managed.		are then independently realized and managed.
	o Hierarchical (i.e., recursive) composition: An IETF Network Slice		o Hierarchical (i.e., recursive) composition: An IETF network slice
	can be further sliced into other network slices. Recursive		can be further sliced into other network slices. Recursive
	composition allows an IETF Network Slice at one layer to be used		composition allows an IETF network slice at one layer to be used
	by the other layers. This type of multi-layer vertical IETF		by the other layers. This type of multi-layer vertical IETF
	Network Slice associates resources at different layers.		network slice associates resources at different layers.
	o Sequential composition: Different IETF Network Slices can be		o Sequential composition: Different IETF network slices can be
	placed into a sequence to provide an end-to-end service. In		placed into a sequence to provide an end-to-end service. In
	sequential composition, each IETF Network Slice would potentially		sequential composition, each IETF network slice would potentially
	support different dataplanes that need to be stitched together.		support different dataplanes that need to be stitched together.
	5. IETF Network Slice Structure		5. IETF Network Slice Structure
	Editor's note: This content of this section merged with Relationship		Editor's note: This content of this section merged with Relationship
	with E2E slice discussion.		with E2E slice discussion.
	An IETF Network Slice is a set of connections among various endpoints		An IETF network slice is a set of connections among various endpoints
	to form a logical network that meets the SLOs agreed upon.		to form a logical network that meets the SLOs agreed upon.
	____________________________		____________________________
	[EP11]------/ /--[EP21]		[EP11]------/ /--[EP21]
	/ /		/ /
	[EP12]----/ IETF Network Slice /----[EP22]		[EP12]----/ IETF Network Slice /----[EP22]
	: / (SLOs e.g. /		: / (SLOs e.g. /
	: / B/W > x bps, Delay < y ms)/		: / B/W > x bps, Delay < y ms)/
	[EP1m]-/___________________________/-------[EP2n]		[EP1m]-/___________________________/-------[EP2n]
	skipping to change at page 10, line 37 ¶		skipping to change at page 10, line 37 ¶
	: `-----------' `-----------' :		: `-----------' `-----------' :
	[EP1m] [EP2n]		[EP1m] [EP2n]
	Legend		Legend
	SLOs in terms of attributes, e.g. BW, delay.		SLOs in terms of attributes, e.g. BW, delay.
	EP: Endpoint		EP: Endpoint
	B/W: Bandwidth		B/W: Bandwidth
	Figure 2: IETF Network slice		Figure 2: IETF Network slice
	Figure 2 illustrates a case where an IETF Network Slice provides		Figure 2 illustrates a case where an IETF network slice provides
	connectivity between a set of endpoints pairs with specific		connectivity between a set of endpoints pairs with specific
	characteristics for each SLO (e.g. guaranteed minimum bandwidth of x		characteristics for each SLO (e.g. guaranteed minimum bandwidth of x
	bps and guaranteed delay of no more than y ms). The endpoints may be		bps and guaranteed delay of no more than y ms). The endpoints may be
	distributed in the underlay networks, and an IETF Network Slice can		distributed in the underlay networks, and an IETF network slice can
	be deployed across multiple network domains. Also, the endpoints on		be deployed across multiple network domains. Also, the endpoints on
	the same IETF Network Slice may belong to the same or different		the same IETF network slice may belong to the same or different
	address spaces.		address spaces.
	IETF Network slice structure fits into a broader concept of end-to-		IETF Network slice structure fits into a broader concept of end-to-
	end network slices. A network operator may be responsible for		end network slices. A network operator may be responsible for
	delivering services over a number of technologies (such as radio		delivering services over a number of technologies (such as radio
	networks) and for providing specific and fine-grained services (such		networks) and for providing specific and fine-grained services (such
	as CCTV feed or High definition realtime traffic data). That		as CCTV feed or High definition realtime traffic data). That
	operator may need to combine slices of various networks to produce an		operator may need to combine slices of various networks to produce an
	end-to-end network service. Each of these networks may include		end-to-end network service. Each of these networks may include
	multiple physical or virtual nodes and may also provide network		multiple physical or virtual nodes and may also provide network
	functions beyond simply carrying of technology-specific protocol data		functions beyond simply carrying of technology-specific protocol data
	units.An end-to-end network slice is defined by the 3GPP as a		units.An end-to-end network slice is defined by the 3GPP as a
	complete logical network that provides a service in its entirety with		complete logical network that provides a service in its entirety with
	a specific assurance to the customer [TS.23.501-3GPP].		a specific assurance to the consumer [TS.23.501-3GPP].
	An end-to-end network slice may be composed from other network slices		An end-to-end network slice may be composed from other network slices
	that include IETF Network Slices. This composition may include the		that include IETF network slices. This composition may include the
	hierarchical (or recursive) use of underlying network slices and the		hierarchical (or recursive) use of underlying network slices and the
	sequential (or stitched) combination of slices of different networks.		sequential (or stitched) combination of slices of different networks.
	6. IETF Network Slice Stakeholders		6. IETF Network Slice Stakeholders
	An IETF Network Slice and its realization involves the following		An IETF network slice and its realization involves the following
	stakeholders and it is relevant to define them for consistent		stakeholders and it is relevant to define them for consistent
	terminology.		terminology.
	Consumer: A consumer is the requester of an IETF Network Slice.		Consumer: A consumer is the requester of an IETF network slice.
	Consumers may request monitoring of SLOs. A consumer may manage		Consumers may request monitoring of SLOs. A consumer may manage
	the IETF Network Slice service directly by interfacing with the		the IETF network slice service directly by interfacing with the
	IETF Network Slice controller or indirectly through an		IETF network slice controller or indirectly through an
	orchestrator.		orchestrator.
	Orchestrator: An orchestrator is an entity that composes different		Orchestrator: An orchestrator is an entity that composes different
	services, resource and network requirements. It interfaces with		services, resource and network requirements. It interfaces with
	the IETF Network Slice controllers.		the IETF network slice controllers.
	IETF Network Slice Controller (NSC): It realizes an IETF Network		IETF Network Slice Controller (NSC): It realizes an IETF network
	Slice in the underlying network, maintains and monitors the run-		lice in the underlying network, maintains and monitors the run-
	time state of resources and topologies associated with it. A		time state of resources and topologies associated with it. A
	well-defined interface is needed between different types of IETF		well-defined interface is needed between different types of IETF
	Network Slice controllers and different types of orchestrators.		network slice controllers and different types of orchestrators.
	An IETF Network Slice operator (or slice operator for short)		An IETF network slice operator (or slice operator for short)
	manages one or more IETF Network Slices using the IETF Network		manages one or more IETF network slices using the IETF network
	Slice Controller(s).		slice Controller(s).
	Network Controller: is a form of network infrastructure controller		Network Controller: is a form of network infrastructure controller
	that offers network resources to NSC to realize a particular		that offers network resources to NSC to realize a particular
	network slice. These may be existing network controllers		network slice. These may be existing network controllers
	associated with one or more specific technologies that may be		associated with one or more specific technologies that may be
	adapted to the function of realizing IETF Network Slices in a		adapted to the function of realizing IETF network slices in a
	network.		network.
	7. IETF Network Slice Controller Interfaces		7. IETF Network Slice Controller Interfaces
	The interworking and interoperability among the different		The interworking and interoperability among the different
	stakeholders to provide common means of provisioning, operating and		stakeholders to provide common means of provisioning, operating and
	monitoring the IETF Network slices is enabled by the following		monitoring the IETF Network slices is enabled by the following
	communication interfaces (see Figure 3).		communication interfaces (see Figure 3).
	NSC Northbound Interface (NBI): The NSC Northbound Interface is an		NSC Northbound Interface (NBI): The NSC Northbound Interface is an
	interface between a consumer's higher level operation system		interface between a consumer's higher level operation system
	(e.g., a network slice orchestrator) and the NSC. It is a		(e.g., a network slice orchestrator) and the NSC. It is a
	technology agnostic interface. The consumer can use this		technology agnostic interface. The consumer can use this
	interface to communicate the requested characteristics and other		interface to communicate the requested characteristics and other
	requirements (i.e., the SLOs) for the IETF Network Slice, and the		requirements (i.e., the SLOs) for the IETF network slice, and the
	NSC can use the interface to report the operational state of an		NSC can use the interface to report the operational state of an
	IETF Network Slice to the consumer.		IETF network slice to the consumer.
	NSC Southbound Interface (SBI): The NSC Southbound Interface is an		NSC Southbound Interface (SBI): The NSC Southbound Interface is an
	interface between the NSC and network controllers. It is		interface between the NSC and network controllers. It is
	technology-specific and may be built around the many network		technology-specific and may be built around the many network
	models defined within the IETF.		models defined within the IETF.
	+------------------------------------------+		+------------------------------------------+
	| Consumer higher level operation system |		| Consumer higher level operation system |
	| (e.g E2E network slice orchestrator) |		| (e.g E2E network slice orchestrator) |
	+------------------------------------------+		+------------------------------------------+
	skipping to change at page 12, line 47 ¶		skipping to change at page 12, line 47 ¶
	| NSC SBI		| NSC SBI
	V		V
	+------------------------------------------+		+------------------------------------------+
	| Network Controllers |		| Network Controllers |
	+------------------------------------------+		+------------------------------------------+
	Figure 3: Interface of IETF Network Slice Controller		Figure 3: Interface of IETF Network Slice Controller
	8. Realizing IETF Network Slice		8. Realizing IETF Network Slice
	Realization of IETF Network Slices is out of scope of this document.		Realization of IETF network slices is out of scope of this document.
	It is a mapping of the definition of the IETF Network Slice to the		It is a mapping of the definition of the IETF network slice to the
	underlying infrastructure and is necessarily technology-specific and		underlying infrastructure and is necessarily technology-specific and
	achieved by the NSC over the SBI.		achieved by the NSC over the SBI.
	The realization can be achieved in a form of either physical or		The realization can be achieved in a form of either physical or
	logical connectivity through VPNs (see, for example,		logical connectivity through VPNs (see, for example,
	[I-D.ietf-teas-enhanced-vpn], a variety of tunneling technologies		[I-D.ietf-teas-enhanced-vpn], a variety of tunneling technologies
	such as Segment Routing, MPLS, etc. Accordingly, endpoints may be		such as Segment Routing, MPLS, etc. Accordingly, endpoints may be
	realized as physical or logical service or network functions.		realized as physical or logical service or network functions.
	9. Isolation in IETF Network Slices		9. Isolation in IETF Network Slices
	Editor's note: This content is a work in progress. The section on		An IETF network slice consumer may request, that the IETF Network
	isolation is too descriptive.
	An IETF Network Slice consumer may request, that the IETF Network
	Slice delivered to them is isolated from any other network slices of		Slice delivered to them is isolated from any other network slices of
	services delivered to any other customers. It is expected that the		services delivered to any other consumers. It is expected that the
	changes to the other network slices of services do not have any		changes to the other network slices of services do not have any
	negative impact on the delivery of the IETF Network Slice. In a more		negative impact on the delivery of the IETF network slice.
	general sense, isolation can be classified in the following ways:
	Traffic Separation: Traffic of one network slice should not be
	subjected to policies and forwarding rules of other network
	slices.
	Interference Avoidance: Changes in other network slices should not
	impact to the SLOs of the network slice. Here the changes in
	other network slice may include the changes in connectivity,
	traffic volume, traffic pattern, etc.
	Service Assurance: In case service degradation is unacceptable due
	to unpredictable network situations producing service degradation
	(e.g., major congestion events, etc.), explicit reservation of
	resources in the network maybe requested for a reduces set IETF
	network slices.
	9.1. Isolation as a Service Requirement		9.1. Isolation as a Service Requirement
	Isolation is an important requirement of IETF network slices for		Isolation may be an important requirement of IETF network slices for
	services like critical services, emergencies, etc. A consumer may		some critical services. A consumer may express this request as an
	express this request through the description of SLOs.		SLO.
	This requirement can be met by simple conformance with other SLOs.		This requirement can be met by simple conformance with other SLOs.
	For example, traffic congestion (interference from other services)		For example, traffic congestion (interference from other services)
	might impact on the latency experienced by an IETF network slice.		might impact on the latency experienced by an IETF network slice.
	Thus, in this example, conformance to a latency SLO would be the		Thus, in this example, conformance to a latency SLO would be the
	primary requirement for delivery of the IETF network slice service,		primary requirement for delivery of the IETF network slice service,
	and isolation from other services might be only a means to that end.		and isolation from other services might be only a means to that end.
	It should be noted that some aspects of isolation may be measurable		It should be noted that some aspects of isolation may be measurable
	by a customer who have the information about the traffic on a number		by a consumer who have the information about the traffic on a number
	of IETF network slices or other services.		of IETF network slices or other services.
	9.2. Isolation in IETF Network Slice Realization		9.2. Isolation in IETF Network Slice Realization
	The isolation requirement can be achieved with existing, in-		Delivery of isolation is achieved in the realization of IETF network
	development, and potential new technologies in IETF.		slices, with existing, in-development, and potential new technologies
			in IETF. It depends on how a network operator decides to operate
			their network and deliver services.
	Isolation may be achieved in the underlying network by various forms		Isolation may be achieved in the underlying network by various forms
	of resource partitioning ranging from dedicated allocation of		of resource partitioning ranging from dedicated allocation of
	resources for a specific IETF network slice, to sharing or resources		resources for a specific IETF network slice, to sharing or resources
	with safeguards. For example, traffic separation between different		with safeguards. For example, traffic separation between different
	IETF network slices may be achieved using VPN technologies, such as		IETF network slices may be achieved using VPN technologies, such as
	L3VPN, L2VPN, EVPN, etc. Interference avoidance may be achieved by		L3VPN, L2VPN, EVPN, etc. Interference avoidance may be achieved by
	network capacity planning, allocating dedicated network resources,		network capacity planning, allocating dedicated network resources,
	traffic policing or shaping, prioritizing in using shared network		traffic policing or shaping, prioritizing in using shared network
	resources, etc. Finally, service continuity may be ensured by		resources, etc. Finally, service continuity may be ensured by
	reserving backup paths for critical traffic, dedicating specific		reserving backup paths for critical traffic, dedicating specific
	network resources for a selected number of network slices, etc.		network resources for a selected number of network slices, etc.
	9.3. Relationship with Isolation in 5G Network Slice
	Editor's note: This 5G subsection should not be added to terminology.
	it does not add value to the definitions.
	In the context of 5G network slice, "isolation level" is listed as
	one of the attributes which can be used to characterize the type of
	network slice [GSMA Generic Network Slice Template]. For 5G network
	slice, different types of isolation are considered, including
	physical and logical isolation. Physical isolation refers to
	different physical network entities, and logical isolation is further
	classified into virtual resource isolation, network function
	isolation and tenant/service isolation.
	10. Security Considerations		10. Security Considerations
	Editor's Note: Need further improvement; work in progress.
	This document specifies terminology and has no direct effect on the		This document specifies terminology and has no direct effect on the
	security of implementations or deployments.		security of implementations or deployments. In this section, a few
			of the security aspects are identified.
	As noted in Section 4.1.2, some aspects of security may be expressed		o Conformance to security constraints: Specific security requests
	in SLOs and so form part of the service delivered as an IETF network		from consumer defined IETF network slices will be mapped to their
	slice. As further mentioned in Section 8, there is an underlying		realization in the unerlay networks. It will be required by
	asumption that traffic presented to an IETF network slice will not be		underlay networks to have capabilities to conform to consumer's
	misdelivered to an endpoint that is not part of that IETF network		requests as some aspects of security may be expressed in SLOs.
	slice.
	Furthermore, the nature of conformance to SLOs means that it should		o IETF network slice controller authentication: Unerlying networks
	not be possible to attack an IETF network slice service by varying		need to be protected against the attacks from an adversary NSC as
	the traffic on other services or slices carried by the same underlay		they can destablize overall network operations. It is
	network. This concern can be strengthened by the stipulation of		particularly critical since an IETF network slice may span across
	"isolation" as an SLO.		different networks, therefore, IETF NSC should have strong
			authentication with each those networks. Futhermore, both SBI and
			NBI need to be secured.
	Note, however, that a customer wanting to secure their data and keep		o Specific isolation criteria: The nature of conformance to
	it private will be responsible for applying appropriate security		isolation requests means that it should not be possible to attack
	measures to their traffic and not depending on the network operator		an IETF network slice service by varying the traffic on other
	that provides the IETF network slice.		services or slices carried by the same underlay network. In
			general, isolation is expected to strengthen the IETF network
			slice security.
			o Data Integrity of an IETF network slice: A consumer wanting to
			secure their data and keep it private will be responsible for
			applying appropriate security measures to their traffic and not
			depending on the network operator that provides the IETF network
			slice. It is expected that for data integrity, a consumer is
			responsible for end-to-end encryption of its own traffic.
			Note: see NGMN document [NGMN_SEC] on 5G network slice security for
			discussion relevant to this section.
	11. IANA Considerations		11. IANA Considerations
	This memo includes no request to IANA.		This memo includes no request to IANA.
	12. Acknowledgment		12. Acknowledgment
	The entire TEAS NS design team and everyone participating in those		The entire TEAS NS design team and everyone participating in those
	discussion has contributed to this draft. Particularly, Eric Gray,		discussion has contributed to this draft. Particularly, Eric Gray,
	Xufeng Liu, Jie Dong, Adrian Farrel, and Jari Arkko for a thorough		Xufeng Liu, Jie Dong, Adrian Farrel, and Jari Arkko for a thorough
	skipping to change at page 16, line 10 ¶		skipping to change at page 15, line 42 ¶
	Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and		Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
	O. Dios, "YANG Data Model for Traffic Engineering (TE)		O. Dios, "YANG Data Model for Traffic Engineering (TE)
	Topologies", draft-ietf-teas-yang-te-topo-22 (work in		Topologies", draft-ietf-teas-yang-te-topo-22 (work in
	progress), June 2019.		progress), June 2019.
	[I-D.nsdt-teas-ns-framework]		[I-D.nsdt-teas-ns-framework]
	Gray, E. and J. Drake, "Framework for Transport Network		Gray, E. and J. Drake, "Framework for Transport Network
	Slices", draft-nsdt-teas-ns-framework-02 (work in		Slices", draft-nsdt-teas-ns-framework-02 (work in
	progress), March 2020.		progress), March 2020.
			[NGMN_SEC]
			NGMN Alliance, "NGMN 5G Security - Network Slicing", April
			2016, <https://www.ngmn.org/wp-content/uploads/Publication
			s/2016/160429_NGMN_5G_Security_Network_Slicing_v1_0.pdf>.
	[PCI] PCI Security Standards Council, "PCI DSS", May 2018,		[PCI] PCI Security Standards Council, "PCI DSS", May 2018,
	<https://www.pcisecuritystandards.org>.		<https://www.pcisecuritystandards.org>.
	[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip		[RFC2681] Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-trip
	Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681,		Delay Metric for IPPM", RFC 2681, DOI 10.17487/RFC2681,
	September 1999, <https://www.rfc-editor.org/info/rfc2681>.		September 1999, <https://www.rfc-editor.org/info/rfc2681>.
	[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network		[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
	Address Translator (Traditional NAT)", RFC 3022,		Address Translator (Traditional NAT)", RFC 3022,
	DOI 10.17487/RFC3022, January 2001,		DOI 10.17487/RFC3022, January 2001,
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