draft-ietf-opsawg-model-automation-framework-06.txt   draft-ietf-opsawg-model-automation-framework-07.txt 
OPSAWG Q. Wu, Ed. OPSAWG Q. Wu, Ed.
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Informational M. Boucadair, Ed. Intended status: Informational M. Boucadair, Ed.
Expires: March 26, 2021 Orange Expires: April 14, 2021 Orange
D. Lopez D. Lopez
Telefonica I+D Telefonica I+D
C. Xie C. Xie
China Telecom China Telecom
L. Geng L. Geng
China Mobile China Mobile
September 22, 2020 October 11, 2020
A Framework for Automating Service and Network Management with YANG A Framework for Automating Service and Network Management with YANG
draft-ietf-opsawg-model-automation-framework-06 draft-ietf-opsawg-model-automation-framework-07
Abstract Abstract
Data models provide a programmatic approach to represent services and Data models provide a programmatic approach to represent services and
networks. Concretely, they can be used to derive configuration networks. Concretely, they can be used to derive configuration
information for network and service components, and state information information for network and service components, and state information
that will be monitored and tracked. Data models can be used during that will be monitored and tracked. Data models can be used during
the service and network management life cycle, such as service the service and network management life cycle, such as service
instantiation, provisioning, optimization, monitoring, diagnostic, instantiation, provisioning, optimization, monitoring, diagnostic,
and assurance. Data models are also instrumental in the automation and assurance. Data models are also instrumental in the automation
of network management, and they can provide closed-loop control for of network management, and they can provide closed-loop control for
adaptive and deterministic service creation, delivery, and adaptive and deterministic service creation, delivery, and
maintenance. maintenance.
This document describes an architecture for service and network This document describes an architecture for service and network
management automation that takes advantage of YANG modeling management automation that takes advantage of YANG modeling
technologies. This architecture is drawn from a network operator technologies. This architecture is drawn from a network operator
perspective irrespective of the origin of a data module; it can thus perspective irrespective of the origin of a data model; it can thus
accommodate modules that are developed outside the IETF. accommodate modules that are developed outside the IETF.
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.
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 March 26, 2021. This Internet-Draft will expire on April 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
skipping to change at page 2, line 29 skipping to change at page 2, line 29
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 . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Acronyms . . . . . . . . . . . . . . . . . . 5 2. Terminology and Acronyms . . . . . . . . . . . . . . . . . . 5
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Architectural Concepts and Goals . . . . . . . . . . . . . . 6 3. Architectural Concepts and Goals . . . . . . . . . . . . . . 7
3.1. Data Models: Layering and Representation . . . . . . . . 6 3.1. Data Models: Layering and Representation . . . . . . . . 7
3.2. Automation of Service Delivery Procedures . . . . . . . . 10 3.2. Automation of Service Delivery Procedures . . . . . . . . 11
3.3. Service Fullfillment Automation . . . . . . . . . . . . . 10 3.3. Service Fullfillment Automation . . . . . . . . . . . . . 12
3.4. YANG Modules Integration . . . . . . . . . . . . . . . . 11 3.4. YANG Modules Integration . . . . . . . . . . . . . . . . 12
4. Functional Blocks and Interactions . . . . . . . . . . . . . 11 4. Functional Blocks and Interactions . . . . . . . . . . . . . 13
4.1. Service Lifecycle Management Procedure . . . . . . . . . 12 4.1. Service Lifecycle Management Procedure . . . . . . . . . 13
4.1.1. Service Exposure . . . . . . . . . . . . . . . . . . 13 4.1.1. Service Exposure . . . . . . . . . . . . . . . . . . 14
4.1.2. Service Creation/Modification . . . . . . . . . . . . 13 4.1.2. Service Creation/Modification . . . . . . . . . . . . 14
4.1.3. Service Optimization . . . . . . . . . . . . . . . . 13 4.1.3. Service Assurance . . . . . . . . . . . . . . . . . . 15
4.1.4. Service Diagnosis . . . . . . . . . . . . . . . . . . 14 4.1.4. Service Optimization . . . . . . . . . . . . . . . . 15
4.1.5. Service Decommission . . . . . . . . . . . . . . . . 14 4.1.5. Service Diagnosis . . . . . . . . . . . . . . . . . . 15
4.2. Service Fullfillment Management Procedure . . . . . . . . 14 4.1.6. Service Decommission . . . . . . . . . . . . . . . . 16
4.2.1. Intended Configuration Provision . . . . . . . . . . 15 4.2. Service Fullfillment Management Procedure . . . . . . . . 16
4.2.2. Configuration Validation . . . . . . . . . . . . . . 15 4.2.1. Intended Configuration Provision . . . . . . . . . . 16
4.2.3. Performance Monitoring/Model-driven Telemetry . . . . 16 4.2.2. Configuration Validation . . . . . . . . . . . . . . 17
4.2.4. Fault Diagnostic . . . . . . . . . . . . . . . . . . 16 4.2.3. Performance Monitoring/Model-driven Telemetry . . . . 17
4.3. Multi-Layer/Multi-Domain Service Mapping . . . . . . . . 16 4.2.4. Fault Diagnostic . . . . . . . . . . . . . . . . . . 17
4.4. Service Decomposing . . . . . . . . . . . . . . . . . . . 17 4.3. Multi-Layer/Multi-Domain Service Mapping . . . . . . . . 18
5. YANG Data Model Integration Examples . . . . . . . . . . . . 17 4.4. Service Decomposing . . . . . . . . . . . . . . . . . . . 18
5.1. L2VPN/L3VPN Service Delivery . . . . . . . . . . . . . . 17 5. YANG Data Model Integration Examples . . . . . . . . . . . . 18
5.2. VN Lifecycle Management . . . . . . . . . . . . . . . . . 19 5.1. L2VPN/L3VPN Service Delivery . . . . . . . . . . . . . . 18
5.3. Event-based Telemetry in the Device Self Management . . . 20 5.2. VN Lifecycle Management . . . . . . . . . . . . . . . . . 21
6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 5.3. Event-based Telemetry in the Device Self Management . . . 22
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 6. Security Considerations . . . . . . . . . . . . . . . . . . . 23
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22 6.1. Service Level . . . . . . . . . . . . . . . . . . . . . . 24
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 22 6.2. Network Level . . . . . . . . . . . . . . . . . . . . . . 24
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 6.3. Device Level . . . . . . . . . . . . . . . . . . . . . . 25
10.1. Normative References . . . . . . . . . . . . . . . . . . 23 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
10.2. Informative References . . . . . . . . . . . . . . . . . 24 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
Appendix A. Layered YANG Modules Examples Overview . . . . . . . 32 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
A.1. Service Models: Definition and Samples . . . . . . . . . 32 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
A.2. Schema Mount . . . . . . . . . . . . . . . . . . . . . . 33 10.1. Normative References . . . . . . . . . . . . . . . . . . 26
A.3. Network Models: Samples . . . . . . . . . . . . . . . . . 33 10.2. Informative References . . . . . . . . . . . . . . . . . 27
A.4. Device Models: Samples . . . . . . . . . . . . . . . . . 36 Appendix A. Layered YANG Modules Examples Overview . . . . . . . 35
A.4.1. Model Composition . . . . . . . . . . . . . . . . . . 38 A.1. Service Models: Definition and Samples . . . . . . . . . 36
A.4.2. Device Management . . . . . . . . . . . . . . . . . . 38 A.2. Schema Mount . . . . . . . . . . . . . . . . . . . . . . 36
A.4.3. Interface Management . . . . . . . . . . . . . . . . 38 A.3. Network Models: Samples . . . . . . . . . . . . . . . . . 37
A.4.4. Some Device Model Examples . . . . . . . . . . . . . 38 A.4. Device Models: Samples . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41 A.4.1. Model Composition . . . . . . . . . . . . . . . . . . 41
A.4.2. Device Management . . . . . . . . . . . . . . . . . . 41
A.4.3. Interface Management . . . . . . . . . . . . . . . . 41
A.4.4. Some Device Model Examples . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44
1. Introduction 1. Introduction
Service management systems usually comprise service activation/ Service management systems usually comprise service activation/
provision and service operation. Current service delivery provision and service operation. Current service delivery
procedures, from the processing of customer's requirements and orders procedures, from the processing of customer's requirements and orders
to service delivery and operation, typically assume the manipulation to service delivery and operation, typically assume the manipulation
of data sequentially into multiple OSS/BSS applications that may be of data sequentially into multiple Operations Support System (OSS) or
managed by different departments within the service provider's Business Support System (BSS) applications that may be managed by
organization (e.g., billing factory, design factory, network different departments within the service provider's organization
operation center). In addition, many of these applications have been (e.g., billing factory, design factory, network operation center).
developed in-house over the years and operate in a silo mode: In addition, many of these applications have been developed in-house
over the years and operate in a silo mode:
o The lack of standard data input/output (i.e., data model) raises o The lack of standard data input/output (i.e., data model) raises
many challenges in system integration and often results in manual many challenges in system integration and often results in manual
configuration tasks. configuration tasks.
o Service fulfillment systems might have a limited visibility on the o Service fulfillment systems might have a limited visibility on the
network state and therefore have slow response to network changes. network state and therefore have slow response to network changes.
Software Defined Networking (SDN) becomes crucial to address these Software Defined Networking (SDN) becomes crucial to address these
challenges. SDN techniques are meant to automate the overall service challenges. SDN techniques are meant to automate the overall service
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Models are key for each of the aforementioned four technical items. Models are key for each of the aforementioned four technical items.
Service and network management automation is an important step to Service and network management automation is an important step to
improve the agility of network operations. Models are also important improve the agility of network operations. Models are also important
to ease integrating multi-vendor solutions. to ease integrating multi-vendor solutions.
YANG [RFC7950] module developers have taken both top-down and bottom- YANG [RFC7950] module developers have taken both top-down and bottom-
up approaches to develop modules [RFC8199] and to establish a mapping up approaches to develop modules [RFC8199] and to establish a mapping
between a network technology and customer requirements at the top or between a network technology and customer requirements at the top or
abstracting common constructs from various network technologies at abstracting common constructs from various network technologies at
the bottom. At the time of writing this document (2020), there are the bottom. At the time of writing this document (2020), there are
many YANG data models including configuration and service models that many YANG data models including configuration and Service Models that
have been specified or are being specified by the IETF. They cover have been specified or are being specified by the IETF. They cover
many of the networking protocols and techniques. However, how these many of the networking protocols and techniques. However, how these
models work together to configure a device, manage a set of devices models work together to configure a function, manage a set of devices
involved in a service, or provide a service is something that is not involved in a service, or provide a service is something that is not
currently documented either within the IETF or other Standards currently documented either within the IETF or other Standards
Development Organizations (SDOs). Development Organizations (SDOs).
Many of the YANG modules listed in this document are used to exchange
data between a NETCONF/RESTCONF clients and servers
[RFC6241][RFC8040]. Nevertheless, YANG is transport independent data
modeling language. It can thus be used independently of NETCONF/
RESTOCNF. For example, YANG can be used to define abstract data
structures [RFC8791] that can be manipulated by other protocols
(e.g., [I-D.ietf-dots-rfc8782-bis]).
This document describes an architectural framework for service and This document describes an architectural framework for service and
network management automation (Section 3) that takes advantage of network management automation (Section 3) that takes advantage of
YANG modeling technologies and investigates how different layer YANG YANG modeling technologies and investigates how different layer YANG
data models interact with each other (e.g., service mapping, model data models interact with each other (e.g., service mapping, model
composing) in the context of service delivery and fulfillment composing) in the context of service delivery and fulfillment
(Section 4). (Section 4). Concretely, the following benefits can be provided:
o Allow for vendor-agnostic interfaces to manage a service and the
underlying network.
o Move from deployment schemes where vendor-specific network
managers are required to a scheme where the entities that are
responsible for orchestrating and controlling services and network
resources provided by multi-vendor devices are unified.
o Ease data inheritance and reusability among the various
architecture layers promoting thus a network-wise provisioning
instead of device-specific configuration.
o Dynamically fed a decision-making process (e.g., Controllers,
Orchestrators) with notifications that will trigger appropriate
actions allowing thus to continuously adjust a network (and thus
involved resources) to comply the intended service to deliver.
This framework is drawn from a network operator perspective This framework is drawn from a network operator perspective
irrespective of the origin of a data module; it can also accommodate irrespective of the origin of a data model; it can also accommodate
modules that are developed outside the IETF. modules that are developed outside the IETF. The document covers
Service Models that are used by an operator to expose its services
and capture service requirements from the customers (including other
operators). Nevertheless, the document does not elaborate on the
communication protocol(s) that makes use of these Service Models in
order to request and deliver a service. Such considerations are out
of the scope.
The document identifies a list of use cases to exemplify the proposed The document identifies a list of use cases to exemplify the proposed
approach (Section 5), but it does not claim nor aim to be exhaustive. approach (Section 5), but it does not claim nor aim to be exhaustive.
Appendix A lists some examples to illustrate the layered YANG modules
view.
2. Terminology and Acronyms 2. Terminology and Acronyms
2.1. Terminology 2.1. Terminology
The following terms are defined in [RFC8309][RFC8199] and are not The following terms are defined in [RFC8309][RFC8199] and are not
redefined here: redefined here:
o Network Operator o Network Operator
o Customer o Customer
o Service o Service
o Data Model o Data Model
o Service Model o Service Model
o Network Element Module o Network Element Module
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aspects of a network infrastructure), including devices and their aspects of a network infrastructure), including devices and their
subsystems, and relevant protocols operating at the link and subsystems, and relevant protocols operating at the link and
network layers across multiple devices. This model corresponds to network layers across multiple devices. This model corresponds to
the Network Configuration Model discussed in [RFC8309]. the Network Configuration Model discussed in [RFC8309].
It can be used by a network operator to allocate resources (e.g., It can be used by a network operator to allocate resources (e.g.,
tunnel resource, topology resource) for the service or schedule tunnel resource, topology resource) for the service or schedule
resources to meet the service requirements defined in a Service resources to meet the service requirements defined in a Service
Model. Model.
Network Domain: Refers to a network partitioning that is usually
followed by network operators to delimit parts of their network.
"access network" and "core network" are examples of network
domains.
Device Model: Refers to the Network Element YANG data model Device Model: Refers to the Network Element YANG data model
described in [RFC8199] or the Device Configuration Model discussed described in [RFC8199] or the Device Configuration Model discussed
in [RFC8309]. in [RFC8309].
Device Models are also used to refer to model a function embedded Device Models are also used to refer to model a function embedded
in a device (e.g., Network Address Translation (NAT) [RFC8512], in a device (e.g., Network Address Translation (NAT) [RFC8512],
Access Control Lists (ACLs) [RFC8519]). Access Control Lists (ACLs) [RFC8519]).
Pipe: Refers to a communication scope where only one-to-one (1:1) Pipe: Refers to a communication scope where only one-to-one (1:1)
communications are allowed. The scope can be identified between communications are allowed. The scope can be identified between
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communications are allowed (e.g., one site to multiple sites). communications are allowed (e.g., one site to multiple sites).
Funnel: Refers to a communication scope where many-to-one (N:1) Funnel: Refers to a communication scope where many-to-one (N:1)
communications are allowed. communications are allowed.
2.2. Acronyms 2.2. Acronyms
The following acronyms are used in the document: The following acronyms are used in the document:
ACL Access Control List ACL Access Control List
AS Autonomous System
CE Customer Edge CE Customer Edge
DBE Data Border Element
E2E End-to-End
ECA Event Condition Action ECA Event Condition Action
L2VPN Layer 2 Virtual Private Network L2VPN Layer 2 Virtual Private Network
L3VPN Layer 3 Virtual Private Network L3VPN Layer 3 Virtual Private Network
L3SM L3VPN Service Model
L3NM L3VPN Network Model
NAT Network Address Translation NAT Network Address Translation
OAM Operations, Administration, and Maintenance OAM Operations, Administration, and Maintenance
OWD One-Way Delay OWD One-Way Delay
PE Provider Edge PE Provider Edge
QoS Quality of Service QoS Quality of Service
RD Route Distinguisher RD Route Distinguisher
RT Route Target RT Route Target
SBE Session Border Element
SDN Software Defined Networking SDN Software Defined Networking
SP Service Provider
TE Traffic Engineering TE Traffic Engineering
VN Virtual Network VN Virtual Network
VPN Virtual Private Network VPN Virtual Private Network
VRF Virtual Routing and Forwarding VRF Virtual Routing and Forwarding
3. Architectural Concepts and Goals 3. Architectural Concepts and Goals
3.1. Data Models: Layering and Representation 3.1. Data Models: Layering and Representation
As described in Section 2 of [RFC8199], layering of modules allows As described in Section 2 of [RFC8199], layering of modules allows
for better reusability of lower-layer modules by higher-level modules for better reusability of lower-layer modules by higher-level modules
while limiting duplication of features across layers. while limiting duplication of features across layers.
Data models can be classified into Service, Network, and Device Data models in the context of network management can be classified
Models. Different Service Models may rely on the same set of Network into Service, Network, and Device Models. Different Service Models
and/or Device Models. may rely on the same set of Network and/or Device Models.
Service Models traditionally follow a top-down approach and are Service Models traditionally follow a top-down approach and are
mostly customer-facing YANG modules providing a common model mostly customer-facing YANG modules providing a common model
construct for higher level network services (e.g., Layer 3 Virtual construct for higher level network services (e.g., Layer 3 Virtual
Private Network (L3VPN)). Such modules can be mapped to network Private Network (L3VPN)). Such modules can be mapped to network
technology-specific modules at lower layers (e.g., tunnel, routing, technology-specific modules at lower layers (e.g., tunnel, routing,
Quality of Service (QoS), security). For example, the service level Quality of Service (QoS), security). For example, Service Models can
can be used to characterise the network service(s) to be ensured be used to characterise the network service(s) to be ensured between
between service nodes (ingress/egress) such as: service nodes (ingress/egress) such as:
o the communication scope (pipe, hose, funnel, ...), o the communication scope (pipe, hose, funnel, ...),
o the directionality (inbound/outbound), o the directionality (inbound/outbound),
o the traffic performance guarantees (One-Way Delay (OWD) [RFC7679], o the traffic performance guarantees expressed using metrics such as
One-Way Loss [RFC7680], ...), One-Way Delay (OWD) [RFC7679] or One-Way Loss [RFC7680]; a summary
o link capacity [RFC5136][I-D.ietf-ippm-capacity-metric-method], of performance metrics maintained by IANA can be found in [IPPM],
o link capacity [RFC5136] [I-D.ietf-ippm-capacity-metric-method],
o etc. o etc.
Figure 1 depicts the example of a VoIP service that relies upon Figure 1 depicts the example of a VoIP service that relies upon
connectivity services offered by a network operator. In this connectivity services offered by a network operator. In this
example, the VoIP service is offered to the network operator's example, the VoIP service is offered to the network operator's
customers by Service Provider (SP1). In order to provide global VoIP customers by Service Provider (SP1). In order to provide global VoIP
reachability, SP1 service site interconnects with other Service reachability, SP1 service site interconnects with other Service
Providers service sites typically by interconnecting Session Border Providers service sites typically by interconnecting Session Border
Elements (SBEs) and Data Border Elements (DBEs) [RFC5486][RFC6406]. Elements (SBEs) and Data Border Elements (DBEs) [RFC5486][RFC6406].
For other VoIP destinations, sessions are forwarded over the For other VoIP destinations, sessions are forwarded over the
Internet. These connectivity services can be captured in a YANG Internet. These connectivity services can be captured in a YANG
Service Module that reflects the service attributes that are shown in Service Model that reflects the service attributes that are shown in
Figure 2. This example follows the IP Connectivity Provisioning Figure 2. This example follows the IP Connectivity Provisioning
Profile template defined in [RFC7297]. Profile template defined in [RFC7297].
,--,--,--. ,--,--,--. ,--,--,--. ,--,--,--.
,-' SP1 `-. ,-' SP2 `-. ,-' SP1 `-. ,-' SP2 `-.
( Service Site ) ( Service Site ) ( Service Site ) ( Service Site )
`-. ,-' `-. ,-' `-. ,-' `-. ,-'
`--'--'--' `--'--'--' `--'--'--' `--'--'--'
x | o * * | x | o * * |
(2)x | o * * | (2)x | o * * |
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Device (and function) Models usually follow a bottom-up approach and Device (and function) Models usually follow a bottom-up approach and
are mostly technology-specific modules used to realize a service are mostly technology-specific modules used to realize a service
(e.g., BGP, NAT). (e.g., BGP, NAT).
Each level maintains a view of the supported YANG modules provided by Each level maintains a view of the supported YANG modules provided by
low-levels (see for example, Appendix A). low-levels (see for example, Appendix A).
Figure 3 illustrates the overall layering model. The reader may Figure 3 illustrates the overall layering model. The reader may
refer to Section 4 of [RFC8309] for an overview of "Orchestrator" and refer to Section 4 of [RFC8309] for an overview of "Orchestrator" and
"Controller" elements. "Controller" elements. All these elements (i.e., Orchestrator(s),
Controller(s), device(s)) are under the responsibility of the same
operator.
+-----------------------------------------------------------------+ +-----------------------------------------------------------------+
| +-----------------------+ | | Hierarchy Abstraction |
| | Orchestrator | Hierarchy Abstraction | | |
| +-----------------------+ Service Model |
| | Orchestrator | (Customer Oriented) |
| |+---------------------+| Scope: "1:1" Pipe model |
| || Service Modeling || |
| |+---------------------+| | | |+---------------------+| |
| || Service Modeling || Service Model |
| |+---------------------+| (Customer Oriented) |
| | | Scope: "1:1" Pipe model |
| | | Bidirectional | | | | Bidirectional |
| |+---------------------+| +-+ Capacity,OWD +-+ | | |+---------------------+| +-+ Capacity,OWD +-+ |
| ||Service Orchestration|| | +----------------+ | | | ||Service Orchestration|| | +----------------+ | |
| |+---------------------+| +-+ +-+ | | |+---------------------+| +-+ +-+ |
| +-----------------------+ 1. Ingress 2. Egress | | +-----------------------+ Ingress Egress |
| |
| | | |
| | | |
| +-----------------------+ Network Model | | +-----------------------+ Network Model |
| | Controller | (Operator Oriented) | | | Controller | (Operator Oriented) |
| |+---------------------+| +-+ +--+ +---+ +-+ | | |+---------------------+| +-+ +--+ +---+ +-+ |
| || Network Modeling || | | | | | | | | | | || Network Modeling || | | | | | | | | |
| |+---------------------+| | o----o--o----o---o---o | | | |+---------------------+| | o----o--o----o---o---o | |
| |+---------------------+| +-+ +--+ +---+ +-+ | | | | +-+ +--+ +---+ +-+ |
| ||Network Orchestration|| src dst | | |+---------------------+| src dst |
| |+---------------------+| L3VPN over TE | | ||Network Orchestration|| L3VPN over TE |
| | | Instance Name/Access Interface | | |+---------------------+| Instance Name/Access Interface |
| +-----------------------+ Protocol Type/Capacity/RD/RT/... | | +-----------------------+ Protocol Type/Capacity/RD/RT/... |
| mapping for hop |
| | | |
| | | |
| +-----------------------+ | | +-----------------------+ Device Model |
| | Device | Device Model | | | Device | |
| |+--------------------+ | | | |+--------------------+ | |
| || Device Modeling | | Interface add, BGP Peer, | | || Device Modeling | | Interface add, BGP Peer, |
| |+--------------------+ | Tunnel ID, QoS/TE, ... | | |+--------------------+ | Tunnel ID, QoS/TE, ... |
| +-----------------------+ | | +-----------------------+ |
+-----------------------------------------------------------------+ +-----------------------------------------------------------------+
Figure 3: Layering and Representation Figure 3: Layering and Representation Within a Network Operator
A composite service offered by a network operator may rely on
services from other operators. In such case, the network operator
acts as a customer to request services from other networks. The
operators providing these services will then follow the layering
depicted in Figure 3. The mapping between a composite service and a
third-party service is maintained at the orchestration level. From a
data plane perspective, appropriate traffic steering policies (e.g.,
Service Function Chaining [RFC7665]) are managed by the network
controllers to guide how/when a third party service is invoked for
flows bound to a composite service.
The layering model depicted in Figure 3 does not make any assumption The layering model depicted in Figure 3 does not make any assumption
about the location of the various entities (e.g., controller, about the location of the various entities (e.g., controller,
orchestrator) within the network. As such, the architecture does not orchestrator) within the network. As such, the architecture does not
preclude deployments where, for example, the controller is embedded preclude deployments where, for example, the controller is embedded
on a device that hosts other functions that are controlled via YANG on a device that hosts other functions that are controlled via YANG
modules. modules.
In order to ease the mapping between layers and data reuse, this In order to ease the mapping between layers and data reuse, this
document focuses on service models that are modelled using YANG. document focuses on Service Models that are modelled using YANG.
Nevertheless, fully compliant with Section 3 of [RFC8309], Figure 3 Nevertheless, fully compliant with Section 3 of [RFC8309], Figure 3
does not preclude service models to be modelled using other data does not preclude Service Models to be modelled using other data
modelling languages than YANG. modelling languages than YANG.
3.2. Automation of Service Delivery Procedures 3.2. Automation of Service Delivery Procedures
Service Models can be used by a network operator to expose its Service Models can be used by a network operator to expose its
services to its customers. Exposing such models allows to automate services to its customers. Exposing such models allows to automate
the activation of service orders and thus the service delivery. One the activation of service orders and thus the service delivery. One
or more monolithic Service Models can be used in the context of a or more monolithic Service Models can be used in the context of a
composite service activation request (e.g., delivery of a caching composite service activation request (e.g., delivery of a caching
infrastructure over a VPN). Such models are used to feed a decision- infrastructure over a VPN). Such models are used to feed a decision-
skipping to change at page 10, line 37 skipping to change at page 11, line 48
management of network resources. Doing so is meant to: management of network resources. Doing so is meant to:
o expose network resources to customers (including other network o expose network resources to customers (including other network
operators) to provide service fulfillment and assurance. operators) to provide service fulfillment and assurance.
o allow customers (or network operators) to dynamically adjust the o allow customers (or network operators) to dynamically adjust the
network resources based on service requirements as described in network resources based on service requirements as described in
Service Models (e.g., Figure 2) and the current network Service Models (e.g., Figure 2) and the current network
performance information described in the telemetry modules. performance information described in the telemetry modules.
Note that it is out of the scope of this document to elaborate on the
communication protocols that are used to implement the interface
between the service ordering (customer) and service order handling
(provider).
3.3. Service Fullfillment Automation 3.3. Service Fullfillment Automation
To operate a service, the settings of the parameters in the Device To operate a service, the settings of the parameters in the Device
Models are derived from Service Models and/or Network Models and are Models are derived from Service Models and/or Network Models and are
used to: used to:
o Provision each involved network function/device with the proper o Provision each involved network function/device with the proper
configuration information. configuration information.
o Operate the network based on service requirements as described in o Operate the network based on service requirements as described in
skipping to change at page 11, line 30 skipping to change at page 12, line 45
service delivery (including, proper network setup). For example, the service delivery (including, proper network setup). For example, the
service parameters captured in Service Models need to be decomposed service parameters captured in Service Models need to be decomposed
into a set of configuration/notification parameters that may be into a set of configuration/notification parameters that may be
specific to one or more technologies; these technology-specific specific to one or more technologies; these technology-specific
parameters are grouped together to define technology-specific device parameters are grouped together to define technology-specific device
level models or network level models. level models or network level models.
In addition, these technology-specific Device or Network Models can In addition, these technology-specific Device or Network Models can
be further integrated with each other using the schema mount be further integrated with each other using the schema mount
mechanism [RFC8528] to provision each involved network function/ mechanism [RFC8528] to provision each involved network function/
device or each involved administrative domain to support newly added device or each involved network domain to support newly added module
module or features. A collection of Device Models integrated or features. A collection of Device Models integrated together can
together can be loaded and validated during implementation. be loaded and validated during implementation.
High-level policies can be defined at Service or Network Models High-level policies can be defined at Service or Network Models
(e.g., "Autonomous System Number (ASN) Exclude" in the example (e.g., "Autonomous System Number (ASN) Exclude" in the example
depicted in Figure 2). Device Models will be tweaked accordingly to depicted in Figure 2). Device Models will be tweaked accordingly to
provide policy-based management. Policies can also be used for provide policy-based management. Policies can also be used for
telemetry automation, e.g., policies that contain conditions can telemetry automation, e.g., policies that contain conditions to
trigger the generation and pushing of new telemetry data. trigger the generation and pushing of new telemetry data.
Performance measurement telemetry can be used to provide service
assurance at Service and/or Network levels. Performance measurement
telemetry model can tie with Service or Network Models to monitor
network performance or Service Level Agreement.
4. Functional Blocks and Interactions 4. Functional Blocks and Interactions
The architectural considerations described in Section 3 lead to the The architectural considerations described in Section 3 lead to the
architecture described in this section and illustrated in Figure 4. architecture described in this section and illustrated in Figure 4.
+------------------+ +------------------+
................. | | ................. | |
Service level | | Service level | |
V | V |
E2E E2E E2E E2E E2E E2E E2E E2E
skipping to change at page 12, line 46 skipping to change at page 14, line 6
Figure 4: Service and Network Lifecycle Management Figure 4: Service and Network Lifecycle Management
4.1. Service Lifecycle Management Procedure 4.1. Service Lifecycle Management Procedure
Service lifecycle management includes end-to-end service lifecycle Service lifecycle management includes end-to-end service lifecycle
management at the service level and technology specific network management at the service level and technology specific network
lifecycle management at the network level. lifecycle management at the network level.
The end-to-end service lifecycle management is technology-independent The end-to-end service lifecycle management is technology-independent
service management and spans across multiple administrative domain or service management and spans across multiple network domains and/or
multiple layers while technology specific service lifecycle multiple layers while technology specific service lifecycle
management is technology domain specific or layer specific service management is technology domain specific or layer specific service
lifecycle management. lifecycle management.
4.1.1. Service Exposure 4.1.1. Service Exposure
A service in the context of this document (sometimes called, Network A service in the context of this document (sometimes called, Network
Service) is some form of connectivity between customer sites and the Service) is some form of connectivity between customer sites and the
Internet or between customer sites across the operator's network and Internet or between customer sites across the operator's network and
across the Internet. across the Internet.
skipping to change at page 13, line 27 skipping to change at page 14, line 33
Service Model catalogs can be created along to expose the various Service Model catalogs can be created along to expose the various
services and the information needed to invoke/order a given service. services and the information needed to invoke/order a given service.
4.1.2. Service Creation/Modification 4.1.2. Service Creation/Modification
A customer is usually unaware of the technology that the network A customer is usually unaware of the technology that the network
operator has available to deliver the service, so the customer does operator has available to deliver the service, so the customer does
not make requests specific to the underlying technology but is not make requests specific to the underlying technology but is
limited to making requests specific to the service that is to be limited to making requests specific to the service that is to be
delivered. This service request can be issued using a Service Model. delivered. This service request can be filled using a Service Model.
Upon receiving a service request, and assuming that appropriate Upon receiving a service request, and assuming that appropriate
authentication and authorization checks have been made, the service authentication and authorization checks have been made with success,
orchestrator/management system should verify whether the service the service orchestrator/management system should verify whether the
requirements in the service request can be met (i.e., whether there service requirements in the service request can be met (i.e., whether
is sufficient resources that can be allocated with the requested there is sufficient resources that can be allocated with the
guarantees). requested guarantees).
If the request is accepted, the service orchestrator/management If the request is accepted, the service orchestrator/management
system maps such service request to its view. This view can be system maps such service request to its view. This view can be
described as a technology specific network model or a set of described as a technology specific Network Model or a set of
technology specific Device Models and this mapping may include a technology specific Device Models and this mapping may include a
choice of which networks and technologies to use depending on which choice of which networks and technologies to use depending on which
service features have been requested. service features have been requested.
In addition, a customer may require to change the underlying network In addition, a customer may require to change the underlying network
infrastructure to adapt to new customer's needs and service infrastructure to adapt to new customer's needs and service
requirements. This service modification can be issued following the requirements. This service modification can be issued following the
same Service Model used by the service request. same Service Model used by the service request.
4.1.3. Service Optimization 4.1.3. Service Assurance
Performance measurement telemetry (Section 4.2) can be used to
provide service assurance at Service and/or Network levels.
Performance measurement telemetry model can tie with Service or
Network Models to monitor network performance or Service Level
Agreement.
4.1.4. Service Optimization
Service optimization is a technique that gets the configuration of Service optimization is a technique that gets the configuration of
the network updated due to network changes, incidents mitigation, or the network updated due to network changes, incidents mitigation, or
new service requirements. One typical example is once a tunnel or a new service requirements. One typical example is once a tunnel or a
VPN is setup, Performance monitoring information or telemetry VPN is setup, Performance monitoring information or telemetry
information per tunnel (or per VPN) can be collected and fed into the information per tunnel (or per VPN) can be collected and fed into the
management system. If the network performance doesn't meet the management system. If the network performance doesn't meet the
service requirements, the management system can create new VPN service requirements, the management system can create new VPN
policies capturing network service requirements and populate them policies capturing network service requirements and populate them
into the network. into the network.
Both network performance information and policies can be modelled Both network performance information and policies can be modelled
using YANG. With Policy-based management, self-configuration and using YANG. With Policy-based management, self-configuration and
self-optimization behavior can be specified and implemented. self-optimization behavior can be specified and implemented.
4.1.4. Service Diagnosis The overall service optimization is managed at the service level,
while the network level is responsible for the optimization of the
specific network services it provides.
4.1.5. Service Diagnosis
Operations, Administration, and Maintenance (OAM) are important Operations, Administration, and Maintenance (OAM) are important
networking functions for service diagnosis that allow network networking functions for service diagnosis that allow network
operators to: operators to:
o monitor network communications (i.e., reachability verification o monitor network communications (i.e., reachability verification
and Continuity Check) and Continuity Check)
o troubleshoot failures (i.e., fault verification and localization) o troubleshoot failures (i.e., fault verification and localization)
skipping to change at page 14, line 40 skipping to change at page 16, line 9
pinpoint the problem and provide recommendations (or instructions) pinpoint the problem and provide recommendations (or instructions)
for the network recovery. for the network recovery.
The service diagnosis information can be modelled as technology- The service diagnosis information can be modelled as technology-
independent Remote Procedure Call (RPC) operations for OAM protocols independent Remote Procedure Call (RPC) operations for OAM protocols
and technology-independent abstraction of key OAM constructs for OAM and technology-independent abstraction of key OAM constructs for OAM
protocols [RFC8531][RFC8533]. These models can be used to provide protocols [RFC8531][RFC8533]. These models can be used to provide
consistent configuration, reporting, and presentation for the OAM consistent configuration, reporting, and presentation for the OAM
mechanisms used to manage the network. mechanisms used to manage the network.
4.1.5. Service Decommission 4.1.6. Service Decommission
Service decommission allows a customer to stop the service by Service decommission allows a customer to stop the service by
removing the service from active status and thus releasing the removing the service from active status and thus releasing the
network resources that were allocated to the service. Customers can network resources that were allocated to the service. Customers can
also use the Service Model to withdraw the registration to a service. also use the Service Model to withdraw the registration to a service.
4.2. Service Fullfillment Management Procedure 4.2. Service Fullfillment Management Procedure
4.2.1. Intended Configuration Provision 4.2.1. Intended Configuration Provision
Intended configuration at the device level is derived from Network Intended configuration at the device level is derived from Network
Models at the network level or Service Model at the service level and Models at the network level or Service Model at the service level and
represents the configuration that the system attempts to apply. Take represents the configuration that the system attempts to apply. Take
L3SM as a Service Model example to deliver a L3VPN service, we need L3SM as a Service Model example to deliver a L3VPN service, there is
to map the L3VPN service view defined in the Service Model into a need to map the L3VPN service view defined in the Service Model
detailed intended configuration view defined by specific into a detailed intended configuration view defined by specific
configuration models for network elements, configuration information configuration models for network elements; the configuration
includes: information includes:
o Virtual Routing and Forwarding (VRF) definition, including VPN o Virtual Routing and Forwarding (VRF) definition, including VPN
policy expression policy expression
o Physical Interface(s) o Physical Interface(s)
o IP layer (IPv4, IPv6) o IP layer (IPv4, IPv6)
o QoS features such as classification, profiles, etc. o QoS features such as classification, profiles, etc.
skipping to change at page 15, line 39 skipping to change at page 17, line 5
o Address sharing (e.g., NAT) o Address sharing (e.g., NAT)
o Security o Security
These specific configuration models can be used to configure Provider These specific configuration models can be used to configure Provider
Edge (PE) and Customer Edge (CE) devices within a site, e.g., a BGP Edge (PE) and Customer Edge (CE) devices within a site, e.g., a BGP
policy model can be used to establish VPN membership between sites policy model can be used to establish VPN membership between sites
and VPN Service Topology. and VPN Service Topology.
Note that in networks with legacy devices (that support proprietary
modules or do not support YANG at all), an adaptation layer is likely
to be required at the network level so that these devices can be
involved in the delivery of the network services.
4.2.2. Configuration Validation 4.2.2. Configuration Validation
Configuration validation is used to validate intended configuration Configuration validation is used to validate intended configuration
and ensure the configuration take effect. and ensure the configuration take effect.
For example, a customer creates an interface "eth-0/0/0" but the For example, a customer creates an interface "eth-0/0/0" but the
interface does not physically exist at this point, then configuration interface does not physically exist at this point, then configuration
data appears in the <intended> status but does not appear in data appears in the <intended> status but does not appear in
<operational> datastore. <operational> datastore.
4.2.3. Performance Monitoring/Model-driven Telemetry 4.2.3. Performance Monitoring/Model-driven Telemetry
When configuration is in effect in the device, <operational> When a configuration is in effect in a device, <operational>
datastore holds the complete operational state of the device datastore holds the complete operational state of the device
including learned, system, default configuration, and system state. including learned, system, default configuration, and system state.
However, the configurations and state of a particular device does not However, the configurations and state of a particular device does not
have the visibility to the whole network or information of the flow have the visibility on the whole network or how packets are going to
packets are going to take through the entire network. Therefore it be forwarded through the entire network. Therefore, it becomes more
becomes more difficult to operate the network without understanding difficult to operate the entire network without understanding the
the current status of the network. current status of the network.
The management system should subscribe to updates of a YANG datastore The management system should subscribe to updates of a YANG datastore
in all the network devices for performance monitoring purpose and in all the network devices for performance monitoring purposes and
build a full topological visibility of the network by aggregating build a full topological visibility of the network by aggregating
(and filtering) these operational state from different sources. (and filtering) these operational state from different sources.
4.2.4. Fault Diagnostic 4.2.4. Fault Diagnostic
When configuration is in effect in the device, some devices may be When configuration is in effect in a device, some devices may be mis-
mis-configured (e.g.,device links are not consistent in both sides of configured (e.g., device links are not consistent in both sides of
the network connection), network resources be mis-allocated and the network connection) or network resources be mis-allocated.
services may be negatively affected without knowing what is going on Therefore, services may be negatively affected without knowing the
in the network. root cause in the network.
Technology-dependent nodes and RPC commands are defined in Technology-dependent nodes and RPC commands are defined in
technology-specific YANG data models which can use and extend the technology-specific YANG data models which can use and extend the
base model described in Section 4.1.4 to deal with these issues. base model described in Section 4.1.5 to deal with these issues.
These RPC commands received in the technology-dependent node can be These RPC commands received in the technology-dependent node can be
used to trigger technology-specific OAM message exchanges for fault used to trigger technology-specific OAM message exchanges for fault
verification and fault isolation For example, TRILL Multicast Tree verification and fault isolation. For example, TRILL Multicast Tree
Verification (MTV) RPC command [I-D.ietf-trill-yang-oam] can be used Verification (MTV) RPC command [I-D.ietf-trill-yang-oam] can be used
to trigger Multi-Destination Tree Verification Message defined in to trigger Multi-Destination Tree Verification Message defined in
[RFC7455] to verify TRILL distribution tree integrity. [RFC7455] to verify TRILL distribution tree integrity.
4.3. Multi-Layer/Multi-Domain Service Mapping 4.3. Multi-Layer/Multi-Domain Service Mapping
Multi-layer/Multi-domain Service Mapping allows to map an end-to-end Multi-layer/Multi-domain Service Mapping allows to map an end-to-end
abstract view of the service segmented at different layers or abstract view of the service segmented at different layers and/or
different administrative domains into domain-specific view. different network domains into domain-specific views.
One example is to map service parameters in L3VPN service model into One example is to map service parameters in the L3SM into
configuration parameters such as Route Distinguisher (RD), Route configuration parameters such as Route Distinguisher (RD), Route
Target (RT), and VRF in L3VPN network model. Target (RT), and VRF in the L3VPN Network Model (L3NM).
Another example is to map service parameters in L3VPN service model Another example is to map service parameters in the L3SM into Traffic
into Traffic Engineered (TE) tunnel parameter (e.g., Tunnel ID) in TE Engineered (TE) tunnel parameter (e.g., Tunnel ID) in TE model and
model and Virtual Network (VN) parameters (e.g., Access Point (AP) Virtual Network (VN) parameters (e.g., Access Point (AP) list, VN
list, VN members) in the YANG data model for VN operation members) in the YANG data model for VN operation
[I-D.ietf-teas-actn-vn-yang]. [I-D.ietf-teas-actn-vn-yang].
4.4. Service Decomposing 4.4. Service Decomposing
Service Decomposing allows to decompose service model at the service Service Decomposing allows to decompose Service Models at the service
level or network model at the network level into a set of device/ level or Network Models at the network level into a set of Device
function models at the device level. These Device Models may be tied Models at the device level. These Device Models may be tied to
to specific device types or classified into a collection of related specific device types or classified into a collection of related YANG
YANG modules based on service types and features offered, and load at modules based on service types and features offered, and load at the
the implementation time before configuration is loaded and validated. implementation time before configuration is loaded and validated.
5. YANG Data Model Integration Examples 5. YANG Data Model Integration Examples
The following subsections provides some YANG data models integration The following subsections provide some YANG data models integration
examples. examples.
5.1. L2VPN/L3VPN Service Delivery 5.1. L2VPN/L3VPN Service Delivery
In reference to Figure 5, the following steps are performed to In reference to Figure 5, the following steps are performed to
deliver the L3VPN service within the network management automation deliver the L3VPN service within the network management automation
architecture defined in this document: architecture defined in Section 4:
1. The Customer requests to create two sites (as per service 1. The Customer requests to create two sites (as per Service
creation operation in Section 4.2.1) relying upon a L3SM Service Creation in Section 4.2.1) relying upon L3SM with each site
model with each having one network access connectivity, for having one network access connectivity, for example:
example:
* Site A: Network-Access A, Link Capacity = 20 Mbps, for class * Site A: network-access A, link-capacity = 20 Mbps, class
"foo", guaranteed-capacity-percent = 10, average-One-Way-Delay "foo", guaranteed-capacity-percent = 10, average-one-way-delay
= 70 ms. = 70 ms.
* Site B: Network-Access B, Link Capacity = 30 Mbps, for class * Site B: network-access B, link-capacity = 30 Mbps, class
"foo1", guaranteed-capacity-percent = 15, average-One-Way- "foo1", guaranteed-capacity-percent = 15, average-one-way-
Delay = 60 ms. delay = 60 ms.
2. The Orchestrator extracts the service parameters from the L3SM 2. The Orchestrator extracts the service parameters from the L3SM.
model. Then, it uses them as input to translate ("service Then, it uses them as input to the Service Mapping in Section 4.3
mapping operation" in Section 4.4) them into an orchestrated to translate them into an orchestrated configuration parameters
configuration of network elements (e.g., RD, RT, VRF) that are (e.g., RD, RT, VRF) that are part of the L3NM specified in
part of the L3VPN Network YANG Model specified in
[I-D.ietf-opsawg-l3sm-l3nm]. [I-D.ietf-opsawg-l3sm-l3nm].
3. The Controller takes orchestrated configuration parameters in the 3. The Controller takes the orchestrated configuration parameters in
L3NM network model and translates them into orchestrated the L3NM and translates them into orchestrated (Service
("service decomposing operation" in ) configuration of network Decomposing in Section 4.4) configuration of network elements
elements that are part of, e.g., BGP, QoS, Network Instance that are part of, e.g., BGP, QoS, Network Instance, IP
model, IP management, and interface models. management, and interface models.
[I-D.ogondio-opsawg-uni-topology] can be used for representing, [I-D.ogondio-opsawg-uni-topology] can be used for representing,
managing, and controlling the User Network Interface (UNI) topology. managing, and controlling the User Network Interface (UNI) topology.
L3SM | L3SM |
Service | Service |
Model | Model |
+----------------------+--------------------------+ +----------------------+--------------------------+
| +--------V--------+ | | +--------V--------+ |
| | Service Mapping | | | | Service Mapping | |
skipping to change at page 19, line 45 skipping to change at page 21, line 45
Note that a similar analysis can be performed for Layer 2 VPNs Note that a similar analysis can be performed for Layer 2 VPNs
(L2VPNs). A L2VPN Service Model (L2SM) is defined in [RFC8466], (L2VPNs). A L2VPN Service Model (L2SM) is defined in [RFC8466],
while the L2VPN Network YANG Model (L2NM) is specified in while the L2VPN Network YANG Model (L2NM) is specified in
[I-D.ietf-opsawg-l2nm]. [I-D.ietf-opsawg-l2nm].
5.2. VN Lifecycle Management 5.2. VN Lifecycle Management
In reference to Figure 7, the following steps are performed to In reference to Figure 7, the following steps are performed to
deliver the VN service within the network management automation deliver the VN service within the network management automation
architecture defined in this document: architecture defined in Section 4:
1. Customer requests (service exposure operation in Section 4.1.1) 1. A customer makes a request (Service Exposure in Section 4.1.1) to
to create 'VN' based on Access point, association between VN and create a VN. The association between the VN, APs, and VN members
Access point, VN member defined in the VN YANG module. is defined in the VN YANG module [I-D.ietf-teas-actn-vn-yang].
2. The orchestrator creates the single abstract node topology based 2. The Orchestrator creates the single abstract node topology based
on the information captured in an VN YANG module. on the information captured in the request.
3. The Customer exchanges connectivity-matrix on abstract node and 3. The customer exchanges with the Orchestrator the connectivity
explicit path using TE topology model with the orchestrator. matrix on the abstract node and explicit paths using the TE
This information can be used to instantiate VN and setup tunnels topology model [RFC8795]. This information can be used to
between source and destination endpoints (service creation instantiate the VN and setup tunnels between source and
operation in Section 4.1.2). destination endpoints (Service Creation in Section 4.1.2).
4. The telemetry model which augments the VN model and corresponding 4. The telemetry model which augments the VN model and corresponding
TE tunnel model can be used to subscribe to performance TE tunnel model can be used to subscribe to performance
measurement data and notify all the parameter changes and network measurement data and notify all the parameter changes and network
performance change related to VN topology or Tunnel performance changes related to VN topology or Tunnel
[I-D.ietf-teas-actn-pm-telemetry-autonomics] and provide service [I-D.ietf-teas-actn-pm-telemetry-autonomics] and provide service
assurance (service optimization operation in Section 4.1.3). assurance (Service Optimization in Section 4.1.4).
| |
VN | VN |
Service | Service |
Model | Model |
+----------------------|--------------------------+ +----------------------|--------------------------+
| Orchestrator | | | Orchestrator | |
| +--------V--------+ | | +--------V--------+ |
| | Service Mapping | | | | Service Mapping | |
| +-----------------+ | | +-----------------+ |
+----------------------+--------------------^-----+ +----------------------+--------------------^-----+
TE | Telemetry TE | Telemetry |
Tunnel | Model Tunnel | Model |
Model | | Model | |
+----------------------V--------------------+-----+ +----------------------V--------------------+-----+
| Controller | | Controller |
| | | |
+-------------------------------------------------+ +-------------------------------------------------+
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| CE1 +------+ PE1 | | PE2 +------+ CE2 | | CE1 +------+ PE1 | | PE2 +------+ CE2 |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 7: A VN Service Delivery Example Figure 7: A VN Service Delivery Example
5.3. Event-based Telemetry in the Device Self Management 5.3. Event-based Telemetry in the Device Self Management
In reference to Figure 8, the following steps are performed to In reference to Figure 8, the following steps are performed to
monitor state changes of managed objects or resources in a network monitor state changes of managed resources in a network device and
device and provide device self-management within the network provide device self-management within the network management
management automation architecture defined in this document: automation architecture defined in Section 4:
1. To control which state a network device should be in or is 1. To control which state a network device should be in or is
allowed to be in at any given time, a set of conditions and allowed to be in at any given time, a set of conditions and
actions are defined and correlated with network events (e.g., actions are defined and correlated with network events (e.g.,
allow the NETCONF server to send updates only when the value allow the NETCONF server to send updates only when the value
exceeds a certain threshold for the first time, but not again exceeds a certain threshold for the first time, but not again
until the threshold is cleared), which constitute ECA policy or until the threshold is cleared), which constitute an
an event-driven policy control logic that can be executed on the Event/Condition/Action (ECA) policy or an event-driven policy
device (e.g., [I-D.wwx-netmod-event-yang]). control logic that can be executed on the device (e.g.,
[I-D.wwx-netmod-event-yang]).
2. To provide rapid autonomic response that can exhibit self- 2. To provide rapid autonomic response that can exhibit self-
management properties, the controller pushes the ECA policy to management properties, the Controller pushes the ECA policy to
the network device and delegates network control logic to the the network device and delegates the network control logic to the
network device. network device.
3. The network device uses the ECA model to subscribe to the event 3. The network device uses the ECA model to subscribe to the event
source, e.g., an event stream or datastore state data conveyed to source, e.g., an event stream or datastore state data conveyed to
the server via YANG Push subscription, monitors state parameters, the server via YANG Push subscription [RFC8641], monitors state
and takes simple and instant actions when associated event parameters, and takes simple and instant actions when associated
condition on state parameters is met. ECA notifications can be event condition on state parameters is met. ECA notifications
generated as the result of actions based on event stream can be generated as the result of actions based on event stream
subscription or datastore subscription (model-driven telemetry subscription or datastore subscription (model-driven telemetry
operation discussed in Section 4.2.3). operation discussed in Section 4.2.3).
+----------------+ +----------------+
| <----+ | <----+
| Controller | | | Controller | |
+-------+--------+ | +-------+--------+ |
| | | |
| | | |
ECA | | ECA ECA | | ECA
skipping to change at page 22, line 14 skipping to change at page 24, line 16
The NETCONF access control model [RFC8341] provides the means to The NETCONF access control model [RFC8341] provides the means to
restrict access for particular NETCONF or RESTCONF users to a restrict access for particular NETCONF or RESTCONF users to a
preconfigured subset of all available NETCONF or RESTCONF protocol preconfigured subset of all available NETCONF or RESTCONF protocol
operations and content. operations and content.
Security considerations specific to each of the technologies and Security considerations specific to each of the technologies and
protocols listed in the document are discussed in the specification protocols listed in the document are discussed in the specification
documents of each of these protocols. documents of each of these protocols.
Security considerations specific to this document are listed below: In order to prevent leaking sensitive information, special care
should be considered when translating between the various layers in
Section 4 or when aggregating data retrieved from various sources.
The network operator must enforce means to protect privacy-related
information included in customer-facing models.
o Create forwarding loops by mis-configuring the underlying network. To detect misalignment between layers that might be induced by
misbehaving nodes, upper layers should continuously monitor the
perceived service (Section 4.1.4) and should proceed with checks to
assess that the provided service complies with the expected service
and that the data reported by an underlying layer is matching the
perceived service by the above layer. Typically, such checks are the
responsibility of the service diagnosis (Section 4.1.5).
o Leak sensitive information: special care should be considered when Additional considerations are discussed in the following subsections.
translating between the various layers in Section 4 or when
aggregating data retrieved from various sources. The network 6.1. Service Level
operator must enforce means to protect privacy-related information
included in cutsomer-facing models. A provider may rely on services offered by other providers to build
composite services. Appropriate mechanisms should be enabled by the
provider to monitor and detect a service disruption from these
providers. The characterization of a service disruption (including,
mean time between failures, mean time to repair), the escalation
procedure, and penalties are usually documented in contractual
agreements (e.g., Section 2.1 of [RFC4176]). Misbehaving peer
providers will thus be identified and appropriate countermeasures
will be applied.
6.2. Network Level
Security considerations specific to the network level are listed
below:
o A controller may create forwarding loops by mis-configuring the
underlying network nodes. It is recommended to proceed with tests
to check the status of forwarding paths regularly or whenever
changes are made to routing or forwarding processes. Such checks
may be triggered from the service level owing to the means
discussed in Section 4.1.5.
o Some Service Models may include a traffic isolation clause, o Some Service Models may include a traffic isolation clause,
appropriate technology-specific actions must be enforced to avoid appropriate technology-specific actions must be enforced at the
that traffic is accessible to non-authorized parties. underlying network (and thus involved network devices) to avoid
that such traffic is accessible to non-authorized parties.
6.3. Device Level
Network operators should monitor and audit their networks to detect
misbehaving nodes and abnormal behaviors. For example, OAM discussed
in Section 4.1.5 can be used for that purpose.
7. IANA Considerations 7. IANA Considerations
There are no IANA requests or assignments included in this document. There are no IANA requests or assignments included in this document.
8. Acknowledgements 8. Acknowledgements
Thanks to Joe Clark, Greg Mirsky, Shunsuke Homma, Brian Carpenter, Thanks to Joe Clark, Greg Mirsky, Shunsuke Homma, Brian Carpenter,
and Adrian Farrel for the review. Adrian Farrel, Christian Huitema, Tommy Pauly, Ines Robles, and
Olivier Augizeau for the review.
Many thanks to Robert Wilton for the detailed AD review. Many thanks to Robert Wilton for the detailed AD review.
9. Contributors 9. Contributors
Christian Jacquenet Christian Jacquenet
Orange Orange
Rennes, 35000 Rennes, 35000
France France
Email: Christian.jacquenet@orange.com Email: Christian.jacquenet@orange.com
skipping to change at page 25, line 5 skipping to change at page 28, line 5
M. Sivakumar, "Yang Data Model for Multicast in MPLS/BGP M. Sivakumar, "Yang Data Model for Multicast in MPLS/BGP
IP VPNs", draft-ietf-bess-mvpn-yang-04 (work in progress), IP VPNs", draft-ietf-bess-mvpn-yang-04 (work in progress),
June 2020. June 2020.
[I-D.ietf-bfd-yang] [I-D.ietf-bfd-yang]
Rahman, R., Zheng, L., Jethanandani, M., Pallagatti, S., Rahman, R., Zheng, L., Jethanandani, M., Pallagatti, S.,
and G. Mirsky, "YANG Data Model for Bidirectional and G. Mirsky, "YANG Data Model for Bidirectional
Forwarding Detection (BFD)", draft-ietf-bfd-yang-17 (work Forwarding Detection (BFD)", draft-ietf-bfd-yang-17 (work
in progress), August 2018. in progress), August 2018.
[I-D.ietf-dots-rfc8782-bis]
Boucadair, M., Shallow, J., and T. Reddy.K, "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Signal
Channel Specification", draft-ietf-dots-rfc8782-bis-01
(work in progress), September 2020.
[I-D.ietf-i2rs-yang-l2-network-topology] [I-D.ietf-i2rs-yang-l2-network-topology]
Dong, J., Wei, X., WU, Q., Boucadair, M., and A. Liu, "A Dong, J., Wei, X., WU, Q., Boucadair, M., and A. Liu, "A
YANG Data Model for Layer 2 Network Topologies", draft- YANG Data Model for Layer 2 Network Topologies", draft-
ietf-i2rs-yang-l2-network-topology-17 (work in progress), ietf-i2rs-yang-l2-network-topology-18 (work in progress),
August 2020. September 2020.
[I-D.ietf-idr-bgp-model] [I-D.ietf-idr-bgp-model]
Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
YANG Model for Service Provider Networks", draft-ietf-idr- YANG Model for Service Provider Networks", draft-ietf-idr-
bgp-model-09 (work in progress), June 2020. bgp-model-09 (work in progress), June 2020.
[I-D.ietf-ippm-capacity-metric-method] [I-D.ietf-ippm-capacity-metric-method]
Morton, A., Geib, R., and L. Ciavattone, "Metrics and Morton, A., Geib, R., and L. Ciavattone, "Metrics and
Methods for IP Capacity", draft-ietf-ippm-capacity-metric- Methods for One-way IP Capacity", draft-ietf-ippm-
method-03 (work in progress), August 2020. capacity-metric-method-04 (work in progress), September
2020.
[I-D.ietf-ippm-stamp-yang] [I-D.ietf-ippm-stamp-yang]
Mirsky, G., Xiao, M., and W. Luo, "Simple Two-way Active Mirsky, G., Min, X., and W. Luo, "Simple Two-way Active
Measurement Protocol (STAMP) Data Model", draft-ietf-ippm- Measurement Protocol (STAMP) Data Model", draft-ietf-ippm-
stamp-yang-05 (work in progress), October 2019. stamp-yang-06 (work in progress), October 2020.
[I-D.ietf-ippm-twamp-yang] [I-D.ietf-ippm-twamp-yang]
Civil, R., Morton, A., Rahman, R., Jethanandani, M., and Civil, R., Morton, A., Rahman, R., Jethanandani, M., and
K. Pentikousis, "Two-Way Active Measurement Protocol K. Pentikousis, "Two-Way Active Measurement Protocol
(TWAMP) Data Model", draft-ietf-ippm-twamp-yang-13 (work (TWAMP) Data Model", draft-ietf-ippm-twamp-yang-13 (work
in progress), July 2018. in progress), July 2018.
[I-D.ietf-mpls-base-yang] [I-D.ietf-mpls-base-yang]
Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A
YANG Data Model for MPLS Base", draft-ietf-mpls-base- YANG Data Model for MPLS Base", draft-ietf-mpls-base-
skipping to change at page 25, line 50 skipping to change at page 29, line 8
progress), February 2020. progress), February 2020.
[I-D.ietf-opsawg-l2nm] [I-D.ietf-opsawg-l2nm]
barguil, s., Dios, O., Boucadair, M., Munoz, L., Jalil, barguil, s., Dios, O., Boucadair, M., Munoz, L., Jalil,
L., and J. Ma, "A Layer 2 VPN Network YANG Model", draft- L., and J. Ma, "A Layer 2 VPN Network YANG Model", draft-
ietf-opsawg-l2nm-00 (work in progress), July 2020. ietf-opsawg-l2nm-00 (work in progress), July 2020.
[I-D.ietf-opsawg-l3sm-l3nm] [I-D.ietf-opsawg-l3sm-l3nm]
barguil, s., Dios, O., Boucadair, M., Munoz, L., and A. barguil, s., Dios, O., Boucadair, M., Munoz, L., and A.
Aguado, "A Layer 3 VPN Network YANG Model", draft-ietf- Aguado, "A Layer 3 VPN Network YANG Model", draft-ietf-
opsawg-l3sm-l3nm-03 (work in progress), April 2020. opsawg-l3sm-l3nm-04 (work in progress), October 2020.
[I-D.ietf-pim-igmp-mld-snooping-yang] [I-D.ietf-pim-igmp-mld-snooping-yang]
Zhao, H., Liu, X., Liu, Y., Sivakumar, M., and A. Peter, Zhao, H., Liu, X., Liu, Y., Sivakumar, M., and A. Peter,
"A Yang Data Model for IGMP and MLD Snooping", draft-ietf- "A Yang Data Model for IGMP and MLD Snooping", draft-ietf-
pim-igmp-mld-snooping-yang-18 (work in progress), August pim-igmp-mld-snooping-yang-18 (work in progress), August
2020. 2020.
[I-D.ietf-pim-yang] [I-D.ietf-pim-yang]
Liu, X., McAllister, P., Peter, A., Sivakumar, M., Liu, Liu, X., McAllister, P., Peter, A., Sivakumar, M., Liu,
Y., and f. hu, "A YANG Data Model for Protocol Independent Y., and f. hu, "A YANG Data Model for Protocol Independent
Multicast (PIM)", draft-ietf-pim-yang-17 (work in Multicast (PIM)", draft-ietf-pim-yang-17 (work in
progress), May 2018. progress), May 2018.
[I-D.ietf-rtgwg-policy-model] [I-D.ietf-rtgwg-policy-model]
Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data
Model for Routing Policy Management", draft-ietf-rtgwg- Model for Routing Policy Management", draft-ietf-rtgwg-
policy-model-21 (work in progress), September 2020. policy-model-26 (work in progress), October 2020.
[I-D.ietf-rtgwg-qos-model] [I-D.ietf-rtgwg-qos-model]
Choudhary, A., Jethanandani, M., Strahle, N., Aries, E., Choudhary, A., Jethanandani, M., Strahle, N., Aries, E.,
and I. Chen, "YANG Model for QoS", draft-ietf-rtgwg-qos- and I. Chen, "YANG Model for QoS", draft-ietf-rtgwg-qos-
model-02 (work in progress), July 2020. model-02 (work in progress), July 2020.
[I-D.ietf-spring-sr-yang] [I-D.ietf-spring-sr-yang]
Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J. Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J.
Tantsura, "YANG Data Model for Segment Routing", draft- Tantsura, "YANG Data Model for Segment Routing", draft-
ietf-spring-sr-yang-22 (work in progress), August 2020. ietf-spring-sr-yang-22 (work in progress), August 2020.
skipping to change at page 26, line 45 skipping to change at page 30, line 6
Monitoring Telemetry and Scaling Intent Autonomics", Monitoring Telemetry and Scaling Intent Autonomics",
draft-ietf-teas-actn-pm-telemetry-autonomics-03 (work in draft-ietf-teas-actn-pm-telemetry-autonomics-03 (work in
progress), July 2020. progress), July 2020.
[I-D.ietf-teas-actn-vn-yang] [I-D.ietf-teas-actn-vn-yang]
Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B. Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B.
Yoon, "A YANG Data Model for VN Operation", draft-ietf- Yoon, "A YANG Data Model for VN Operation", draft-ietf-
teas-actn-vn-yang-09 (work in progress), July 2020. teas-actn-vn-yang-09 (work in progress), July 2020.
[I-D.ietf-teas-yang-path-computation] [I-D.ietf-teas-yang-path-computation]
Busi, I., Belotti, S., Lopezalvarez, V., Sharma, A., and Busi, I., Belotti, S., Lopez, V., Sharma, A., and Y. Shi,
Y. Shi, "Yang model for requesting Path Computation", "Yang model for requesting Path Computation", draft-ietf-
draft-ietf-teas-yang-path-computation-10 (work in teas-yang-path-computation-10 (work in progress), July
progress), July 2020. 2020.
[I-D.ietf-teas-yang-rsvp-te] [I-D.ietf-teas-yang-rsvp-te]
Beeram, V., Saad, T., Gandhi, R., Liu, X., Bryskin, I., Beeram, V., Saad, T., Gandhi, R., Liu, X., Bryskin, I.,
and H. Shah, "A YANG Data Model for RSVP-TE Protocol", and H. Shah, "A YANG Data Model for RSVP-TE Protocol",
draft-ietf-teas-yang-rsvp-te-08 (work in progress), March draft-ietf-teas-yang-rsvp-te-08 (work in progress), March
2020. 2020.
[I-D.ietf-teas-yang-te] [I-D.ietf-teas-yang-te]
Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin, Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
"A YANG Data Model for Traffic Engineering Tunnels, Label "A YANG Data Model for Traffic Engineering Tunnels, Label
skipping to change at page 27, line 41 skipping to change at page 30, line 47
Xu, "A YANG Model for Network and VPN Service Performance Xu, "A YANG Model for Network and VPN Service Performance
Monitoring", draft-www-bess-yang-vpn-service-pm-06 (work Monitoring", draft-www-bess-yang-vpn-service-pm-06 (work
in progress), April 2020. in progress), April 2020.
[I-D.wwx-netmod-event-yang] [I-D.wwx-netmod-event-yang]
Bierman, A., WU, Q., Bryskin, I., Birkholz, H., Liu, X., Bierman, A., WU, Q., Bryskin, I., Birkholz, H., Liu, X.,
and B. Claise, "A YANG Data model for ECA Policy and B. Claise, "A YANG Data model for ECA Policy
Management", draft-wwx-netmod-event-yang-09 (work in Management", draft-wwx-netmod-event-yang-09 (work in
progress), July 2020. progress), July 2020.
[IPPM] IANA, "Performance Metrics", March 2020,
<https://www.iana.org/assignments/performance-metrics/
performance-metrics.xhtml>.
[RFC4176] El Mghazli, Y., Ed., Nadeau, T., Boucadair, M., Chan, K.,
and A. Gonguet, "Framework for Layer 3 Virtual Private
Networks (L3VPN) Operations and Management", RFC 4176,
DOI 10.17487/RFC4176, October 2005,
<https://www.rfc-editor.org/info/rfc4176>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>. 2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer [RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer
2 Virtual Private Networks (L2VPNs)", RFC 4664, 2 Virtual Private Networks (L2VPNs)", RFC 4664,
DOI 10.17487/RFC4664, September 2006, DOI 10.17487/RFC4664, September 2006,
<https://www.rfc-editor.org/info/rfc4664>. <https://www.rfc-editor.org/info/rfc4664>.
[RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private [RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
skipping to change at page 29, line 15 skipping to change at page 32, line 30
[RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for
System Management", RFC 7317, DOI 10.17487/RFC7317, August System Management", RFC 7317, DOI 10.17487/RFC7317, August
2014, <https://www.rfc-editor.org/info/rfc7317>. 2014, <https://www.rfc-editor.org/info/rfc7317>.
[RFC7455] Senevirathne, T., Finn, N., Salam, S., Kumar, D., Eastlake [RFC7455] Senevirathne, T., Finn, N., Salam, S., Kumar, D., Eastlake
3rd, D., Aldrin, S., and Y. Li, "Transparent 3rd, D., Aldrin, S., and Y. Li, "Transparent
Interconnection of Lots of Links (TRILL): Fault Interconnection of Lots of Links (TRILL): Fault
Management", RFC 7455, DOI 10.17487/RFC7455, March 2015, Management", RFC 7455, DOI 10.17487/RFC7455, March 2015,
<https://www.rfc-editor.org/info/rfc7455>. <https://www.rfc-editor.org/info/rfc7455>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>.
[RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, [RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Delay Metric for IP Performance Metrics Ed., "A One-Way Delay Metric for IP Performance Metrics
(IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January (IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
2016, <https://www.rfc-editor.org/info/rfc7679>. 2016, <https://www.rfc-editor.org/info/rfc7679>.
[RFC7680] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, [RFC7680] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Loss Metric for IP Performance Metrics Ed., "A One-Way Loss Metric for IP Performance Metrics
(IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, January (IPPM)", STD 82, RFC 7680, DOI 10.17487/RFC7680, January
2016, <https://www.rfc-editor.org/info/rfc7680>. 2016, <https://www.rfc-editor.org/info/rfc7680>.
skipping to change at page 31, line 39 skipping to change at page 35, line 5
Raghavan, "A YANG Data Model for Retrieval Methods for the Raghavan, "A YANG Data Model for Retrieval Methods for the
Management of Operations, Administration, and Maintenance Management of Operations, Administration, and Maintenance
(OAM) Protocols That Use Connectionless Communications", (OAM) Protocols That Use Connectionless Communications",
RFC 8533, DOI 10.17487/RFC8533, April 2019, RFC 8533, DOI 10.17487/RFC8533, April 2019,
<https://www.rfc-editor.org/info/rfc8533>. <https://www.rfc-editor.org/info/rfc8533>.
[RFC8632] Vallin, S. and M. Bjorklund, "A YANG Data Model for Alarm [RFC8632] Vallin, S. and M. Bjorklund, "A YANG Data Model for Alarm
Management", RFC 8632, DOI 10.17487/RFC8632, September Management", RFC 8632, DOI 10.17487/RFC8632, September
2019, <https://www.rfc-editor.org/info/rfc8632>. 2019, <https://www.rfc-editor.org/info/rfc8632>.
[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.
[RFC8652] Liu, X., Guo, F., Sivakumar, M., McAllister, P., and A. [RFC8652] Liu, X., Guo, F., Sivakumar, M., McAllister, P., and A.
Peter, "A YANG Data Model for the Internet Group Peter, "A YANG Data Model for the Internet Group
Management Protocol (IGMP) and Multicast Listener Management Protocol (IGMP) and Multicast Listener
Discovery (MLD)", RFC 8652, DOI 10.17487/RFC8652, November Discovery (MLD)", RFC 8652, DOI 10.17487/RFC8652, November
2019, <https://www.rfc-editor.org/info/rfc8652>. 2019, <https://www.rfc-editor.org/info/rfc8652>.
[RFC8675] Boucadair, M., Farrer, I., and R. Asati, "A YANG Data [RFC8675] Boucadair, M., Farrer, I., and R. Asati, "A YANG Data
Model for Tunnel Interface Types", RFC 8675, Model for Tunnel Interface Types", RFC 8675,
DOI 10.17487/RFC8675, November 2019, DOI 10.17487/RFC8675, November 2019,
<https://www.rfc-editor.org/info/rfc8675>. <https://www.rfc-editor.org/info/rfc8675>.
skipping to change at page 32, line 15 skipping to change at page 35, line 30
[RFC8676] Farrer, I., Ed. and M. Boucadair, Ed., "YANG Modules for [RFC8676] Farrer, I., Ed. and M. Boucadair, Ed., "YANG Modules for
IPv4-in-IPv6 Address plus Port (A+P) Softwires", RFC 8676, IPv4-in-IPv6 Address plus Port (A+P) Softwires", RFC 8676,
DOI 10.17487/RFC8676, November 2019, DOI 10.17487/RFC8676, November 2019,
<https://www.rfc-editor.org/info/rfc8676>. <https://www.rfc-editor.org/info/rfc8676>.
[RFC8783] Boucadair, M., Ed. and T. Reddy.K, Ed., "Distributed [RFC8783] Boucadair, M., Ed. and T. Reddy.K, Ed., "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Data Denial-of-Service Open Threat Signaling (DOTS) Data
Channel Specification", RFC 8783, DOI 10.17487/RFC8783, Channel Specification", RFC 8783, DOI 10.17487/RFC8783,
May 2020, <https://www.rfc-editor.org/info/rfc8783>. May 2020, <https://www.rfc-editor.org/info/rfc8783>.
[RFC8791] Bierman, A., Bjoerklund, M., and K. Watsen, "YANG Data
Structure Extensions", RFC 8791, DOI 10.17487/RFC8791,
June 2020, <https://www.rfc-editor.org/info/rfc8791>.
[RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and [RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Gonzalez de Dios, "YANG Data Model for Traffic O. Gonzalez de Dios, "YANG Data Model for Traffic
Engineering (TE) Topologies", RFC 8795, Engineering (TE) Topologies", RFC 8795,
DOI 10.17487/RFC8795, August 2020, DOI 10.17487/RFC8795, August 2020,
<https://www.rfc-editor.org/info/rfc8795>. <https://www.rfc-editor.org/info/rfc8795>.
Appendix A. Layered YANG Modules Examples Overview Appendix A. Layered YANG Modules Examples Overview
This appendix lists a set of YANG data models that can be used for This appendix lists a set of YANG data models that can be used for
the delivery of connectivity services. These models can be the delivery of connectivity services. These models can be
skipping to change at page 33, line 7 skipping to change at page 36, line 27
transfer capability characterized by a (Source Nets, Destination transfer capability characterized by a (Source Nets, Destination
Nets, Guarantees, Scope) tuple where "Source Nets" is a group of Nets, Guarantees, Scope) tuple where "Source Nets" is a group of
unicast IP addresses, "Destination Nets" is a group of IP unicast unicast IP addresses, "Destination Nets" is a group of IP unicast
and/or multicast addresses, and "Guarantees" reflects the guarantees and/or multicast addresses, and "Guarantees" reflects the guarantees
(expressed in terms of QoS, performance, and availability, for (expressed in terms of QoS, performance, and availability, for
example) to properly forward traffic to the said "Destination" example) to properly forward traffic to the said "Destination"
[RFC7297]. [RFC7297].
For example: For example:
o The L3SM model [RFC8299] defines the L3VPN service ordered by a o The L3SM [RFC8299] defines the L3VPN service ordered by a customer
customer from a network operator. from a network operator.
o The L2SM model [RFC8466] defines the L2VPN service ordered by a o The L2SM [RFC8466] defines the L2VPN service ordered by a customer
customer from a network operator. from a network operator.
o The Virtual Network (VN) model [I-D.ietf-teas-actn-vn-yang] o The Virtual Network (VN) model [I-D.ietf-teas-actn-vn-yang]
provides a YANG data model applicable to any mode of VN operation. provides a YANG data model applicable to any mode of VN operation.
L2SM and L3SM are customer service models as per [RFC8309]. L2SM and L3SM are customer Service Models as per [RFC8309].
A.2. Schema Mount A.2. Schema Mount
Modularity and extensibility were among the leading design principles Modularity and extensibility were among the leading design principles
of the YANG data modeling language. As a result, the same YANG of the YANG data modeling language. As a result, the same YANG
module can be combined with various sets of other modules and thus module can be combined with various sets of other modules and thus
form a data model that is tailored to meet the requirements of a form a data model that is tailored to meet the requirements of a
specific use case. [RFC8528] defines a mechanism, denoted schema specific use case. [RFC8528] defines a mechanism, denoted schema
mount, that allows for mounting one data model consisting of any mount, that allows for mounting one data model consisting of any
number of YANG modules at a specified location of another (parent) number of YANG modules at a specified location of another (parent)
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