A Framework for Automating Service and Network Management with YANG
draft-wu-model-driven-management-virtualization-06
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|---|---|---|---|
| Authors | Qin Wu , Mohamed Boucadair , Christian Jacquenet , Luis M. Contreras , Diego Lopez , Chongfeng Xie , Weiqiang Cheng , Liang Geng , Young Lee | ||
| Last updated | 2019-10-10 (Latest revision 2019-07-03) | ||
| Replaced by | draft-ietf-opsawg-model-automation-framework, RFC 8969 | ||
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| Consensus boilerplate | Unknown | ||
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draft-wu-model-driven-management-virtualization-06
Networking Working Group Q. Wu
Internet-Draft Huawei
Intended status: Informational M. Boucadair
Expires: April 12, 2020 C. Jacquenet
Orange
L. Miguel Contreras Murillo
Telifonica
D. Lopez
Telefonica I+D
C. Xie
China Telecom
W. Cheng
L. Geng
China Mobile
Y. Lee
Futurewei
October 10, 2019
A Framework for Automating Service and Network Management with YANG
draft-wu-model-driven-management-virtualization-06
Abstract
Data models for service and network management provides a
programmatic approach for representing (virtual) services or networks
and deriving (1) configuration information that will be communicated
to network and service components that are used to build and deliver
the service and (2) state information that will be monitored and
tracked. Indeed, data models can be used during various phases of
the service and network management life cycle, such as service
instantiation, service provisioning, optimization, monitoring, and
diagnostic. Also, data models are instrumental in the automation of
network management. They also provide closed-loop control for the
sake of adaptive and deterministic service creation, delivery, and
maintenance.
This document provides a framework that describes and discusses an
architecture for service and network management automation that takes
advantage of YANG modeling technologies. This framework is drawn
from a network provider perspective irrespective of the origin of a
data module; it can accommodate even modules that are developed
outside the IETF.
The document aims to exemplify an approach that specifies the journey
from technology-agnostic services to technology-specific actions.
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Status of This Memo
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This Internet-Draft will expire on April 12, 2020.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Architectural Concepts & Goals . . . . . . . . . . . . . . . 5
3.1. Data Models: Layering and Representation . . . . . . . . 5
3.2. Automation of Service Delivery Procedures . . . . . . . . 7
3.3. Service Fullfillment Automation . . . . . . . . . . . . . 8
3.4. YANG Modules Integration . . . . . . . . . . . . . . . . 8
4. Architecture Overview . . . . . . . . . . . . . . . . . . . . 9
4.1. Service Lifecycle Management Procedure . . . . . . . . . 10
4.1.1. Service Exposure . . . . . . . . . . . . . . . . . . 11
4.1.2. Service Creation/Modification . . . . . . . . . . . . 11
4.1.3. Service Optimization . . . . . . . . . . . . . . . . 11
4.1.4. Service Diagnosis . . . . . . . . . . . . . . . . . . 12
4.1.5. Service Decommission . . . . . . . . . . . . . . . . 12
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4.2. Service Fullfillment Management Procedure . . . . . . . . 12
4.2.1. Intended Configuration Provision . . . . . . . . . . 12
4.2.2. Configuration Validation . . . . . . . . . . . . . . 13
4.2.3. Operational State Telemetry . . . . . . . . . . . . . 13
4.2.4. Fault Diagnostic . . . . . . . . . . . . . . . . . . 13
4.3. Multi-layer/Multi-domain Service Mapping . . . . . . . . 14
4.4. Service Decomposing . . . . . . . . . . . . . . . . . . . 14
5. YANG Data Model Integration Examples . . . . . . . . . . . . 14
5.1. L3VPN Service Delivery . . . . . . . . . . . . . . . . . 14
5.2. VN Lifecycle Management Example . . . . . . . . . . . . . 16
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
9. Informative References . . . . . . . . . . . . . . . . . . . 17
Appendix A. Layered YANG Modules Example Overview . . . . . . . 25
A.1. Service Models: Definition and Samples . . . . . . . . . 25
A.2. Network Models: Definitions and Samples . . . . . . . . . 26
A.3. Device Models: Definitions and Samples . . . . . . . . . 28
A.3.1. Model Composition . . . . . . . . . . . . . . . . . . 29
A.3.2. Device Models: Definitions and Samples . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction
The service management system usually comprises service activation/
provision and service operation. Current service delivery
procedures, from the processing of customer's requirements and order
to service delivery and operation, typically assume the manipulation
of data sequentially into multiple OSS/BSS applications that may be
managed by different departments within the service provider's
organization (e.g., billing factory, design factory, network
operation center, etc.). In addition, many of these applications
have been developed in-house over the years and operating in a silo
mode:
o The lack of standard data input/output (i.e., data model) also
raises many challenges in system integration and often results in
manual configuration tasks.
o Secondly, many current service fulfillment might not support real
time streaming telemetry capability in high frequency and in high
throughput on the current state of networking and therefore have
slow response to the network changes.
Software Defined Networking (SDN) becomes crucial to address these
challenges. SDN techniques [RFC7149] are meant to automate the
overall service delivery procedures and typically rely upon
(standard) data models that are used to not only reflect service
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providers'savoir-faire but also to dynamically instantiate and
enforce a set of (service-inferred) policies that best accommodate
what has been (contractually) defined (and possibly negotiated) with
the customer. [RFC7149] provides a first tentative to rationalize
that service provider's view on the SDN space by identifying concrete
technical domains that need to be considered and for which solutions
can be provided:
o Techniques for the dynamic discovery of topology, devices, and
capabilities, along with relevant information and data models that
are meant to precisely document such topology, devices, and their
capabilities.
o Techniques for exposing network services [RFC8309] and their
characteristics.
o Techniques used by service-requirement-derived dynamic resource
allocation and policy enforcement schemes, so that networks can be
programmed accordingly.
o Dynamic feedback mechanisms that are meant to assess how
efficiently a given policy (or a set thereof) is enforced from a
service fulfillment and assurance perspective.
Models are key for each of these technical items. Service and
network management automation is an important step to improve the
agility of network operations and infrastructures. Models are also
important to ease integrating multi-vendor solutions.
YANG module developers have taken both top-down and bottom-up
approaches to develop modules [RFC8199], and also to establish a
mapping between network technology and customer requirements on the
top or abstracting common construct from various network technologies
on the bottom. At the time of writing this document (2019), there
are many data models including configuration and service models that
have been specified or are being specified by the IETF. They cover
many of the networking protocols and techniques. However, how these
models work together to configure a device, manage a set of devices
involved in a service, or even provide a service is something that is
not currently documented either within the IETF or other SDOs (e.g.,
MEF).
This document provides a framework that describes and discusses an
architecture for service and network management automation that takes
advantage of YANG modeling technologies and investigates how
different layer YANG data models interact with each other (e.g.,
service mapping, model composing) in the context of service delivery
and fulfillment.
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This framework is drawn from a network provider perspective
irrespective of the origin of a data module; it can accommodate even
modules that are developed outside the IETF.
The document also identifies a list of use cases to exemplify the
proposed approach, but it does not claim to be exhaustive.
It is not the intent of this document to provide an inventory of
tools and mechanisms used in specific network and service management
domains; such inventory can be found in documents such as [RFC7276].
2. Terminology
The following terms are defined in [RFC8309][RFC8199] and are not
redefined here:
o Network Operator
o Customer
o Service
o Data Model
o Service Model
o Network Element Module
The document makes use of the following terms:
Network Resource Model: is used by a network operator to allocate a
network resource (e.g., tunnel resource, topology resource) for
the service or schedule the resource to meet the service
requirements captured in a Service Model.
Device Model: Network Element YANG data module described in
[RFC8199].
3. Architectural Concepts & Goals
3.1. Data Models: Layering and Representation
As described in [RFC8199], layering of modules allows for better
reusability of lower-layer modules by higher-level modules while
limiting duplication of features across layers.
The data modules developed by the IETF can be classified into service
level, network level, and device level modules. Different service
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level modules may rely on the same set of network level or device
level modules.
Service level modules usually follow top down approach and are mostly
customer-facing modules providing a common model construct for higher
level network services (e.g., L3VPN), which can be further mapped to
network technology-specific modules at lower layer (e.g., tunnel,
routing, QoS, security). For example, the service level can be used
to characterise the network service(s) to be ensured between service
nodes (ingress/egress) such as the communication scope (pipe, hose,
funnel, ...), the directionality, the traffic performance guarantees
(one-way delay (OWD), one-way loss, ...), etc.
Network level modules mostly follow a bottom-up approach and are
mainly network resource-facing modules and describe various aspects
of a network infrastructure, including devices and their subsystems,
and relevant protocols operating at the link and network layers
across multiple devices (e.g., Network topology and traffic-
engineering Tunnel modules).
Device (and function) level modules usually follow a bottom-up
approach and are mostly technology-specific modules used to realize a
service (e.g., BGP, NAT).
Each level maintains a view of the supported YANG modules provided by
low-levels (see for example, Appendix A).
Figure 1 illustrates the overall layering model.
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+-----------------------------------------------------------------+
| +-----------------------+ |
| | Orchestrator | Hierarchy Abstraction |
| |+---------------------+| |
| || Service Modeling || Service Model |
| |+---------------------+| (Customer Oriented) |
| | | Scope: "1:1" Pipe model |
| | | Bidirectional |
| |+---------------------+| +-+ BW:100M,OWD +-+ |
| ||Service Orchestration|| | +---------------+ | |
| |+---------------------+| +-+ +-+ |
| +-----------------------+ 1. Ingress 2. Egress |
| |
| |
| |
| +-----------------------+ Network Model |
| | Controller | (Operator Oriented) |
| |+---------------------+| +-+ +--+ +---+ +-+ |
| || Network Modeling || | | | | | | | | |
| |+---------------------+| | o----o--o----o---o---o | |
| |+---------------------+| +-+ +--+ +---+ +-+ |
| ||network Orchestration| src dst |
| |+---------------------+| L3VPN over TE |
| | | Instance Name/Access Interface|
| +-----------------------+ Proto Type/BW/RD,RT,..mapping |
| for hop |
| |
| |
| +-----------------------+ |
| | Device | Device Model |
| |+--------------------+ | |
| || Device Modeling | | Interface add,BGP Peer, |
| |+--------------------+ | Tunnel id,QoS/TE config |
| +-----------------------+ |
+-----------------------------------------------------------------+
Figure 1: Layering and representation
3.2. Automation of Service Delivery Procedures
To dynamically offer and deliver service offerings, Service level
modules can be used by an operator. One or more monolithic Service
modules can be used in the context of a composite service activation
request (e.g., delivery of a caching infrastructure over a VPN).
Such modules are used to feed a decision-making intelligence to
adequately accommodate customer's needs.
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Also, such modules may be used jointly with services that require
dynamic invocation. An example is provided by the service modules
defined by the DOTS WG to dynamically trigger requests to handle DDoS
attacks [I-D.ietf-dots-signal-channel][I-D.ietf-dots-data-channel].
Network level modules can be derived from service level modules and
used to provision, monitor, instantiate the service, and provide
lifecycle management of network resources (e.g., expose network
resources to customers or operators to provide service fulfillment
and assurance and allow customers or operators to dynamically adjust
the network resources based on service requirements as described in
service level modules and the current network performance information
described in the telemetry modules).
3.3. Service Fullfillment Automation
To operate the service, Device level modules derived from Service
level modules or Network level modules can be used to provision each
involved network function/device with the proper configuration
information, and operate the network based on service requirements as
described in the Service level module(s).
In addition, the operational state including configuration that is in
effect together with statistics should be exposed to upper layers to
provide better network visibility (and assess to what extent the
derived low level modules are consistent with the upper level
inputs).
Note that it is important to correlate telemetry data with
configuration data to be used for closed loops at the different
stages of service delivery, from resource allocation to service
operation, in particular.
3.4. YANG Modules Integration
To support top-down service delivery, YANG modules at different level
or at the same level need to be integrated together to enable
function, feature in the network device and get network setup. For
example, the service parameters captured in service level modules
need to be decomposed into a set of (configuration/notification)
parameters that may be specific to one or more technologies; these
technology-specific parameters are grouped together to define
technology-specific device level models or network level models.
In addition, these technology-specific device level models or network
level models can be further integrated with each other using schema
mount mechanism [RFC8528] to provision each involved network
function/device or each involved administrative domain to support
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newly added module or features. A collection of device models
integrated together can be loaded and validated during implementation
time.
Policies provide a higher layer of abstraction. Policy models can be
defined at service level, network level, or device level to provide
policy-based management and telemetry automation,e.g., telemetry data
can trigger a new policy that captures new network service
requirements.
Performance measurement telemetry can be used to provide service
assurance at service level or at the network level. Performance
measurement telemetry model can tie with network level model or
service level model to monitor network performance or service level
agreement.
4. Architecture Overview
The architectural considerations described in Section 3 lead to the
architecture described in this section and illustrated in Figure 2.
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+------------------+
Service level | |
----------- V |
E2E E2E E2E
Service -- Service --------> Service --->Service ---+
Exposure Creation ^ Optimization | Diagnosis |
/Modification | | |
| |Diff | V
Multi-layer | | E2E | E2E
Multi-domain | | Service | Service
Service Mapping| +------ Assurance ---+ Decommission
| ^
|<-----------------+ |
Network level | | +----+
------------ V | |
Specific Specific | Specific
Service ----+---> Service ---+--+-> Service --+
Creation ^ Optimization | | Diagnosis |
/Modification | | | V
| |Diff | | Specific
| | Specific----+ | Service
Service | | Service | Decommission
Decomposing | +------Assurance -----+
| ^
| | Aggregation
Device level | +------------+
------------ V |
Service Intent Operational
Fulfillment Config ------> Config ----> State -->Fault
Provision Validate Telemetry Diagnostic
Figure 2: Service and Network Lifecycle Management
4.1. Service Lifecycle Management Procedure
Service lifecycle management includes end to end service lifecycle
management at the service level and specific network lifecycle
management at the network level. The end-to-end service lifecycle
management is multi-domain or multi-layer service management while
specific service lifecycle management is domain specific or layer
specific service lifecycle management.
o Note: Clarify what is meant by "domain".
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4.1.1. Service Exposure
A service in the context of this document (sometimes called a Network
Service) is some form of connectivity between customer sites and the
Internet or between customer sites across the network operator's
network and across the Internet.
Service exposure is used to capture services offered to customers
(ordering and order handling). One typical example is that a
customer can use a L3SM service model to request L3VPN service by
providing the abstract technical characterization of the intended
service between cutsomer sites.
Service model catalogs can be created along to expose the various
services and the information needed to invoke/order a given service.
4.1.2. Service Creation/Modification
A customer is (usually) unaware of the technology that the network
operator has available to deliver the service, so the customer does
not make requests specific to the underlying technology but is
limited to making requests specific to the service that is to be
delivered. This service request can be issued using the service
model.
The service orchestrator/management system maps such service request
to its view. This view can be described as a network model and this
mapping may include a choice of which networks and technologies to
use depending on which service features have been requested.
In addition, a customer may require to change underlying network
infrastructure to adapt to new customer's needs and service
requirements. This service modification can be issued in the same
service model used by the service request.
4.1.3. Service Optimization
Service optimization is a technique that gets the configuration of
the network updated due to network change, incident mitigation, or
new service requirements. One typical example is once the tunnel or
the VPN is setup, Performance monitoring information or telemetry
information per tunnel or per VPN can be collected and fed into the
management system, if the network performance doesn't meet the
service requirements, the management system can create new VPN
policies capturing network service requirements and populate them
into the network.
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Both network performance information and policies can be modelled
using YANG. With Policy-based management, self-configuration and
self-optimization behavior can be specified and implemented.
4.1.4. Service Diagnosis
Operations, Administration, and Maintenance (OAM) are important
networking functions for service diagnosis that allow operators to:
o monitor network communications (i.e., reachability verification
and Continuity Check)
o troubleshoot failures (i.e., fault verification and localization)
o monitor service-level agreements and performance (i.e.,
performance management)
When the network is down, service diagnosis should be in place to
pinpoint the problem and provide recommendation (or instructions) for
the network recovery.
The service diagnosis information can be modelled as technology-
independent RPC operations for OAM protocols and technology-
independent abstraction of key OAM constructs for OAM protocols
[RFC8531][RFC8533]. These models can provide consistent
configuration, reporting, and presentation for the OAM mechanisms
used to manage the network.
4.1.5. Service Decommission
Service decommission allow the customer to stop the service and
remove the service from active status and release the network
resource that is allocated to the service. Customer can also use the
service model to withdraw the subscription to a service.
4.2. Service Fullfillment Management Procedure
4.2.1. Intended Configuration Provision
Intended configuration at the device level is derived from network
model at the network level or service model at the service level and
represents the configuration that the system attempts to apply. Take
L3SM service model as an example, to deliver a L3VPN service, we need
to map L3VPN service view defined in Service model into detailed
intended configuration view defined by specific configuration models
for network elements, configuration information includes:
o VRF definition, including VPN Policy expression
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o Physical Interface
o IP layer (IPv4, IPv6)
o QoS features such as classification, profiles, etc.
o Routing protocols: support of configuration of all protocols
listed in the document, as well as routing policies associated
with those protocols.
o Multicast Support
o NAT or address sharing
o Security function
This specific configuration models can be used to configure PE and CE
devices within the site, e.g., A BGP policy model can be used to
establish VPN membership between sites and VPN Service Topology.
4.2.2. Configuration Validation
Configuration validation is used to validate intended configuration
and ensure the configuration take effect. For example, a customer
creates an interface "et-0/0/0" but the interface does not physically
exist at this point, then configuration data appears in the
<intended> status but does not appear in <operational> datastore.
4.2.3. Operational State Telemetry
<operational> datastore holds the complete operational state of the
device including learned, system, default configuration and system
state. <operational> datastore can be used as telemetry data source
and allows the client subscribe to updates of a YANG datastore.
Based on criteria negotiated as part of a subscription, updates will
be pushed to targeted recipients using YANG push mechanism [RFC8641].
4.2.4. Fault Diagnostic
Technology-dependent nodes and remote procedure call (RPC) commands
are defined in technology-specific YANG modules which use and extend
the base model described in Section 4.1.4.
These RPC commands received in the technology dependent node can be
used to trigger technology specific OAM message exchange for fault
verification and fault isolation.
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4.3. Multi-layer/Multi-domain Service Mapping
Multi-layer/Multi-domain Service Mapping allow you map end to end
abstract view of the service segmented at different layer or
different administrative domain into domain specific view. One
example is to map service parameters in L3VPN service model into
configuration parameters such as RD, RT, and VRF in L3VPN network
model. Another example is to map service parameters in L3VPN service
model into TE tunnel parameter (e.g.,Tunnel ID) in TE model and VN
parameters (e.g., AP list, VN member) in TEAS VN model [I-D.ietf-
teas-actn-vn-yang].
4.4. Service Decomposing
Service Decomposing allows to decompose service model at the service
level or network model at the network level into a set of device/
function models at the device level. These device models may be tied
to specific device type or classified into a collection of related
YANG modules based on service type and feature offered and load at
the implementation time before configuration is loaded and validated.
5. YANG Data Model Integration Examples
5.1. L3VPN Service Delivery
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L3SM |
Service |
Model |
+--------------------+----------------------------+
| +-----V- -------+ |
| Orchestrator |Service Mapping| |
| +-----+---------+ |
| | |
+--------------------+----------------------------+
L3NM |
Network|
Model |
+--------------------+----------------------------+
| Controller+--------V-----------+ |
| | Service Decomposing| |
| +-++------------++---+ |
| || || |
| || || |
+-------------++---------- ++--------------------+
|| ||
|| ||
||BGP,QoS ||
|| ||
+----------+|NI,Intf,IP |+-----------------+
+--+--+ +++---+ --+---+ +--+--+
| CE1 |------| PE1 | | PE2 | ---------+ CE2 |
+-----+ +-----+ +-----+ +-----+
Figure 3: L3VPN Service Delivery Example
In reference to Figure 3, the following steps are performed to
deliver the L3VPN service within the network management automation
architecture defined in this document:
1. Customer Requests to create two sites based on L3SM Service model
with each having one network access connectivity:
Site A: Network-Access A, Bandwidth=20M, for class "foo",
guaranteed-bw-percent = 10, One-Way-Delay=70 msec
Site B: Network-Access B, Bandwidth=30M, for class "foo1",
guaranteed-bw-percent = 15, One-Way-Delay=60 msec
2. The Orchestrator extracts the service parameters from the L3SM
model. Then, it uses them as input to translate them into an
orchestrated configuration of network elements (e.g., RD, RT,
VRF, etc.) that is part of the L3NM network model.
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3. The Controller takes orchestrated configuration parameters in the
L3NM network model and translates them into orchestrated
configuration of network elements that is part of BGP model, QoS
model, Network Instance model, IP management model, interface
model, etc.
5.2. VN Lifecycle Management Example
|
VN |
Service |
Model |
+------------------- --|--------------------------+
| Orchestrator | |
| +--------V--------+ +----------+ |
| | Service Mapping | +-+ECA Engine| |
| +-----------------+ | +--------^-+ |
+----------------------+----------+----------+----+
TE | ECA | Telemetry
Tunnel | Policy| Model
Model | | |
+----------------------V----------V----------+----+
| Controller |
| |
+-------------------------------------------------+
+-----+ +-----+ +-----+ +-----+
| CE1 |------| PE1 | | PE2 |---------+ CE2 |
+-----+ +-----+ +-----+ +-----+
Figure 4
In reference to Figure 4, the following steps are performed to
deliver the VN service within the network management automation
architecture defined in this document:
1. Customer requests to create 'VN' based on Access point,
association between VN and Access point, VN member defined in the
VN YANG module.
2. The orchestrator creates the single abstract node topology based
on the information captured in an VN YANG module.
3. The Customer exchanges connectivity-matrix on abstract node and
explicit path using TE topology model with the orchestrator.
This information can be used to instantiate VN and setup tunnels
between source and destination endpoints.
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4. The telemetry which augments the TEAS VN model and corresponding
TE Tunnel model can be used to notify all the parameter changes
and network performance change related to VN topology or Tunnel
[I-D.ietf-teas-actn-pm-telemetry-autonomics]. This information
can be further used as input to ECA engine in the orchestrator
and generate ECA policy model to optimize the network.
6. Security Considerations
Security considerations specific to each of the technologies and
protocols listed in the document are discussed in the specification
documents of each of these techniques.
(Potential) security considerations specific to this document are
listed below:
o Create forwarding loops by mis-configuring the underlying network.
o Leak sensitive information: special care should be considered when
translating between the various layers introduced in the document.
o ...tbc
7. IANA Considerations
There are no IANA requests or assignments included in this document.
8. Acknowledgements
Thanks to Joe Clark, Greg Mirsky, and Shunsuke Homma for the review.
9. Informative References
[I-D.arkko-arch-virtualization]
Arkko, J., Tantsura, J., Halpern, J., and B. Varga,
"Considerations on Network Virtualization and Slicing",
draft-arkko-arch-virtualization-01 (work in progress),
March 2018.
[I-D.asechoud-netmod-diffserv-model]
Choudhary, A., Shah, S., Jethanandani, M., Liu, B., and N.
Strahle, "YANG Model for Diffserv", draft-asechoud-netmod-
diffserv-model-03 (work in progress), June 2015.
[I-D.clacla-netmod-model-catalog]
Clarke, J. and B. Claise, "YANG module for
yangcatalog.org", draft-clacla-netmod-model-catalog-03
(work in progress), April 2018.
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[I-D.homma-slice-provision-models]
Homma, S., Nishihara, H., Miyasaka, T., Galis, A., OV, V.,
Lopez, D., Contreras, L., Ordonez-Lucena, J., Martinez-
Julia, P., Qiang, L., Rokui, R., Ciavaglia, L., and X.
Foy, "Network Slice Provision Models", draft-homma-slice-
provision-models-01 (work in progress), July 2019.
[I-D.ietf-bess-evpn-yang]
Brissette, P., Shah, H., Hussain, I., Tiruveedhula, K.,
and J. Rabadan, "Yang Data Model for EVPN", draft-ietf-
bess-evpn-yang-07 (work in progress), March 2019.
[I-D.ietf-bess-l2vpn-yang]
Shah, H., Brissette, P., Chen, I., Hussain, I., Wen, B.,
and K. Tiruveedhula, "YANG Data Model for MPLS-based
L2VPN", draft-ietf-bess-l2vpn-yang-10 (work in progress),
July 2019.
[I-D.ietf-bess-l3vpn-yang]
Jain, D., Patel, K., Brissette, P., Li, Z., Zhuang, S.,
Liu, X., Haas, J., Esale, S., and B. Wen, "Yang Data Model
for BGP/MPLS L3 VPNs", draft-ietf-bess-l3vpn-yang-04 (work
in progress), October 2018.
[I-D.ietf-bfd-yang]
Rahman, R., Zheng, L., Jethanandani, M., Networks, J., and
G. Mirsky, "YANG Data Model for Bidirectional Forwarding
Detection (BFD)", draft-ietf-bfd-yang-17 (work in
progress), August 2018.
[I-D.ietf-ccamp-alarm-module]
Vallin, S. and M. Bjorklund, "YANG Alarm Module", draft-
ietf-ccamp-alarm-module-09 (work in progress), April 2019.
[I-D.ietf-ccamp-flexigrid-media-channel-yang]
Madrid, U., Perdices, D., Lopezalvarez, V., Dios, O.,
King, D., Lee, Y., and G. Galimberti, "YANG data model for
Flexi-Grid media-channels", draft-ietf-ccamp-flexigrid-
media-channel-yang-02 (work in progress), March 2019.
[I-D.ietf-ccamp-flexigrid-yang]
Madrid, U., Perdices, D., Lopezalvarez, V., King, D., and
Y. Lee, "YANG data model for Flexi-Grid Optical Networks",
draft-ietf-ccamp-flexigrid-yang-04 (work in progress),
July 2019.
Wu, et al. Expires April 12, 2020 [Page 18]
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[I-D.ietf-ccamp-l1csm-yang]
Lee, Y., Lee, K., Zheng, H., Dhody, D., Dios, O., and D.
Ceccarelli, "A YANG Data Model for L1 Connectivity Service
Model (L1CSM)", draft-ietf-ccamp-l1csm-yang-10 (work in
progress), September 2019.
[I-D.ietf-ccamp-mw-yang]
Ahlberg, J., Ye, M., Li, X., Spreafico, D., and M.
Vaupotic, "A YANG Data Model for Microwave Radio Link",
draft-ietf-ccamp-mw-yang-13 (work in progress), November
2018.
[I-D.ietf-ccamp-otn-topo-yang]
Zheng, H., Guo, A., Busi, I., Sharma, A., Liu, X.,
Belotti, S., Xu, Y., Wang, L., and O. Dios, "A YANG Data
Model for Optical Transport Network Topology", draft-ietf-
ccamp-otn-topo-yang-08 (work in progress), September 2019.
[I-D.ietf-ccamp-otn-tunnel-model]
Zheng, H., Guo, A., Busi, I., Sharma, A., Rao, R.,
Belotti, S., Lopezalvarez, V., Li, Y., and Y. Xu, "OTN
Tunnel YANG Model", draft-ietf-ccamp-otn-tunnel-model-07
(work in progress), July 2019.
[I-D.ietf-ccamp-wson-tunnel-model]
Lee, Y., Zheng, H., Guo, A., Lopezalvarez, V., King, D.,
Yoon, B., and R. Vilata, "A Yang Data Model for WSON
Tunnel", draft-ietf-ccamp-wson-tunnel-model-04 (work in
progress), September 2019.
[I-D.ietf-dots-data-channel]
Boucadair, M. and R. K, "Distributed Denial-of-Service
Open Threat Signaling (DOTS) Data Channel Specification",
draft-ietf-dots-data-channel-31 (work in progress), July
2019.
[I-D.ietf-dots-signal-channel]
K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-37 (work in progress), July 2019.
[I-D.ietf-idr-bgp-model]
Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
YANG Model for Service Provider Networks", draft-ietf-idr-
bgp-model-07 (work in progress), October 2019.
Wu, et al. Expires April 12, 2020 [Page 19]
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[I-D.ietf-ippm-stamp-yang]
Mirsky, G., Xiao, M., and W. Luo, "Simple Two-way Active
Measurement Protocol (STAMP) Data Model", draft-ietf-ippm-
stamp-yang-04 (work in progress), September 2019.
[I-D.ietf-ippm-twamp-yang]
Civil, R., Morton, A., Rahman, R., Jethanandani, M., and
K. Pentikousis, "Two-Way Active Measurement Protocol
(TWAMP) Data Model", draft-ietf-ippm-twamp-yang-13 (work
in progress), July 2018.
[I-D.ietf-mpls-base-yang]
Saad, T., Raza, K., Gandhi, R., Liu, X., and V. Beeram, "A
YANG Data Model for MPLS Base", draft-ietf-mpls-base-
yang-11 (work in progress), September 2019.
[I-D.ietf-pim-igmp-mld-snooping-yang]
Zhao, H., Liu, X., Liu, Y., Sivakumar, M., and A. Peter,
"A Yang Data Model for IGMP and MLD Snooping", draft-ietf-
pim-igmp-mld-snooping-yang-08 (work in progress), June
2019.
[I-D.ietf-pim-igmp-mld-yang]
Liu, X., Guo, F., Sivakumar, M., McAllister, P., and A.
Peter, "A YANG Data Model for Internet Group Management
Protocol (IGMP) and Multicast Listener Discovery (MLD)",
draft-ietf-pim-igmp-mld-yang-15 (work in progress), June
2019.
[I-D.ietf-pim-yang]
Liu, X., McAllister, P., Peter, A., Sivakumar, M., Liu,
Y., and f. hu, "A YANG Data Model for Protocol Independent
Multicast (PIM)", draft-ietf-pim-yang-17 (work in
progress), May 2018.
[I-D.ietf-rtgwg-device-model]
Lindem, A., Berger, L., Bogdanovic, D., and C. Hopps,
"Network Device YANG Logical Organization", draft-ietf-
rtgwg-device-model-02 (work in progress), March 2017.
[I-D.ietf-rtgwg-policy-model]
Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data
Model for Routing Policy Management", draft-ietf-rtgwg-
policy-model-07 (work in progress), September 2019.
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[I-D.ietf-softwire-iftunnel]
Boucadair, M., Farrer, I., and R. Asati, "Tunnel Interface
Types YANG Module", draft-ietf-softwire-iftunnel-07 (work
in progress), June 2019.
[I-D.ietf-softwire-yang]
Farrer, I. and M. Boucadair, "YANG Modules for IPv4-in-
IPv6 Address plus Port (A+P) Softwires", draft-ietf-
softwire-yang-16 (work in progress), January 2019.
[I-D.ietf-spring-sr-yang]
Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J.
Tantsura, "YANG Data Model for Segment Routing", draft-
ietf-spring-sr-yang-13 (work in progress), July 2019.
[I-D.ietf-supa-generic-policy-data-model]
Halpern, J. and J. Strassner, "Generic Policy Data Model
for Simplified Use of Policy Abstractions (SUPA)", draft-
ietf-supa-generic-policy-data-model-04 (work in progress),
June 2017.
[I-D.ietf-teas-actn-vn-yang]
Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., and B.
Yoon, "A Yang Data Model for VN Operation", draft-ietf-
teas-actn-vn-yang-06 (work in progress), July 2019.
[I-D.ietf-teas-sf-aware-topo-model]
Bryskin, I., Liu, X., Lee, Y., Guichard, J., Contreras,
L., Ceccarelli, D., and J. Tantsura, "SF Aware TE Topology
YANG Model", draft-ietf-teas-sf-aware-topo-model-03 (work
in progress), March 2019.
[I-D.ietf-teas-te-service-mapping-yang]
Lee, Y., Dhody, D., Fioccola, G., WU, Q., Ceccarelli, D.,
and J. Tantsura, "Traffic Engineering (TE) and Service
Mapping Yang Model", draft-ietf-teas-te-service-mapping-
yang-02 (work in progress), September 2019.
[I-D.ietf-teas-yang-l3-te-topo]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Dios, "YANG Data Model for Layer 3 TE Topologies",
draft-ietf-teas-yang-l3-te-topo-05 (work in progress),
July 2019.
[I-D.ietf-teas-yang-path-computation]
Busi, I. and S. Belotti, "Yang model for requesting Path
Computation", draft-ietf-teas-yang-path-computation-06
(work in progress), July 2019.
Wu, et al. Expires April 12, 2020 [Page 21]
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[I-D.ietf-teas-yang-rsvp-te]
Beeram, V., Saad, T., Gandhi, R., Liu, X., Bryskin, I.,
and H. Shah, "A YANG Data Model for RSVP-TE Protocol",
draft-ietf-teas-yang-rsvp-te-07 (work in progress), July
2019.
[I-D.ietf-teas-yang-sr-te-topo]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
S. Litkowski, "YANG Data Model for SR and SR TE
Topologies", draft-ietf-teas-yang-sr-te-topo-05 (work in
progress), July 2019.
[I-D.ietf-teas-yang-te]
Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
"A YANG Data Model for Traffic Engineering Tunnels and
Interfaces", draft-ietf-teas-yang-te-21 (work in
progress), April 2019.
[I-D.ietf-teas-yang-te-topo]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Dios, "YANG Data Model for Traffic Engineering (TE)
Topologies", draft-ietf-teas-yang-te-topo-22 (work in
progress), June 2019.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4664] Andersson, L., Ed. and E. Rosen, Ed., "Framework for Layer
2 Virtual Private Networks (L2VPNs)", RFC 4664,
DOI 10.17487/RFC4664, September 2006,
<https://www.rfc-editor.org/info/rfc4664>.
[RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and
Signaling", RFC 4761, DOI 10.17487/RFC4761, January 2007,
<https://www.rfc-editor.org/info/rfc4761>.
[RFC4762] Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
<https://www.rfc-editor.org/info/rfc4762>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>.
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[RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined
Networking: A Perspective from within a Service Provider
Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014,
<https://www.rfc-editor.org/info/rfc7149>.
[RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
Weingarten, "An Overview of Operations, Administration,
and Maintenance (OAM) Tools", RFC 7276,
DOI 10.17487/RFC7276, June 2014,
<https://www.rfc-editor.org/info/rfc7276>.
[RFC7297] Boucadair, M., Jacquenet, C., and N. Wang, "IP
Connectivity Provisioning Profile (CPP)", RFC 7297,
DOI 10.17487/RFC7297, July 2014,
<https://www.rfc-editor.org/info/rfc7297>.
[RFC8077] Martini, L., Ed. and G. Heron, Ed., "Pseudowire Setup and
Maintenance Using the Label Distribution Protocol (LDP)",
STD 84, RFC 8077, DOI 10.17487/RFC8077, February 2017,
<https://www.rfc-editor.org/info/rfc8077>.
[RFC8194] Schoenwaelder, J. and V. Bajpai, "A YANG Data Model for
LMAP Measurement Agents", RFC 8194, DOI 10.17487/RFC8194,
August 2017, <https://www.rfc-editor.org/info/rfc8194>.
[RFC8199] Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module
Classification", RFC 8199, DOI 10.17487/RFC8199, July
2017, <https://www.rfc-editor.org/info/rfc8199>.
[RFC8299] Wu, Q., Ed., Litkowski, S., Tomotaki, L., and K. Ogaki,
"YANG Data Model for L3VPN Service Delivery", RFC 8299,
DOI 10.17487/RFC8299, January 2018,
<https://www.rfc-editor.org/info/rfc8299>.
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/info/rfc8309>.
[RFC8328] Liu, W., Xie, C., Strassner, J., Karagiannis, G., Klyus,
M., Bi, J., Cheng, Y., and D. Zhang, "Policy-Based
Management Framework for the Simplified Use of Policy
Abstractions (SUPA)", RFC 8328, DOI 10.17487/RFC8328,
March 2018, <https://www.rfc-editor.org/info/rfc8328>.
[RFC8345] Clemm, A., Medved, J., Varga, R., Bahadur, N.,
Ananthakrishnan, H., and X. Liu, "A YANG Data Model for
Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March
2018, <https://www.rfc-editor.org/info/rfc8345>.
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[RFC8346] Clemm, A., Medved, J., Varga, R., Liu, X.,
Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model
for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346,
March 2018, <https://www.rfc-editor.org/info/rfc8346>.
[RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
Routing Management (NMDA Version)", RFC 8349,
DOI 10.17487/RFC8349, March 2018,
<https://www.rfc-editor.org/info/rfc8349>.
[RFC8466] Wen, B., Fioccola, G., Ed., Xie, C., and L. Jalil, "A YANG
Data Model for Layer 2 Virtual Private Network (L2VPN)
Service Delivery", RFC 8466, DOI 10.17487/RFC8466, October
2018, <https://www.rfc-editor.org/info/rfc8466>.
[RFC8512] Boucadair, M., Ed., Sivakumar, S., Jacquenet, C.,
Vinapamula, S., and Q. Wu, "A YANG Module for Network
Address Translation (NAT) and Network Prefix Translation
(NPT)", RFC 8512, DOI 10.17487/RFC8512, January 2019,
<https://www.rfc-editor.org/info/rfc8512>.
[RFC8513] Boucadair, M., Jacquenet, C., and S. Sivakumar, "A YANG
Data Model for Dual-Stack Lite (DS-Lite)", RFC 8513,
DOI 10.17487/RFC8513, January 2019,
<https://www.rfc-editor.org/info/rfc8513>.
[RFC8519] Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
"YANG Data Model for Network Access Control Lists (ACLs)",
RFC 8519, DOI 10.17487/RFC8519, March 2019,
<https://www.rfc-editor.org/info/rfc8519>.
[RFC8528] Bjorklund, M. and L. Lhotka, "YANG Schema Mount",
RFC 8528, DOI 10.17487/RFC8528, March 2019,
<https://www.rfc-editor.org/info/rfc8528>.
[RFC8529] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
Liu, "YANG Data Model for Network Instances", RFC 8529,
DOI 10.17487/RFC8529, March 2019,
<https://www.rfc-editor.org/info/rfc8529>.
[RFC8530] Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
Liu, "YANG Model for Logical Network Elements", RFC 8530,
DOI 10.17487/RFC8530, March 2019,
<https://www.rfc-editor.org/info/rfc8530>.
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[RFC8531] Kumar, D., Wu, Q., and Z. Wang, "Generic YANG Data Model
for Connection-Oriented Operations, Administration, and
Maintenance (OAM) Protocols", RFC 8531,
DOI 10.17487/RFC8531, April 2019,
<https://www.rfc-editor.org/info/rfc8531>.
[RFC8532] Kumar, D., Wang, Z., Wu, Q., Ed., Rahman, R., and S.
Raghavan, "Generic YANG Data Model for the Management of
Operations, Administration, and Maintenance (OAM)
Protocols That Use Connectionless Communications",
RFC 8532, DOI 10.17487/RFC8532, April 2019,
<https://www.rfc-editor.org/info/rfc8532>.
[RFC8533] Kumar, D., Wang, M., Wu, Q., Ed., Rahman, R., and S.
Raghavan, "A YANG Data Model for Retrieval Methods for the
Management of Operations, Administration, and Maintenance
(OAM) Protocols That Use Connectionless Communications",
RFC 8533, DOI 10.17487/RFC8533, April 2019,
<https://www.rfc-editor.org/info/rfc8533>.
Appendix A. Layered YANG Modules Example Overview
A.1. Service Models: Definition and Samples
As described in [RFC8309], the service is "some form of connectivity
between customer sites and the Internet and/or between customer sites
across the network operator's network and across the Internet". More
concretely, an IP connectivity service can be defined as the IP
transfer capability characterized by a (Source Nets, Destination
Nets, Guarantees, Scope) tuple where "Source Nets" is a group of
unicast IP addresses, "Destination Nets" is a group of IP unicast
and/or multicast addresses, and "Guarantees" reflects the guarantees
(expressed in terms of Quality Of Service (QoS), performance, and
availability, for example) to properly forward traffic to the said
"Destination" [RFC7297].
For example:
o L3SM model [RFC8299] defines the L3VPN service ordered by a
customer from a network operator.
o L2SM model [RFC8466] defines the L2VPN service ordered by a
customer from a network operator.
o VN model [I-D.ietf-teas-actn-vn-yang]provides a YANG data model
generally applicable to any mode of Virtual Network (VN)
operation.
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A.2. Network Models: Definitions and Samples
Figure 5 depicts a set of Network models such as topology models or
tunnel models:
| |
Topo YANG modules | Tunnel YANG modules |
------------------------------------------------|
+------------+ | |
|Network Top | | +------+ +-----------+ |
| Model | | |Other | | TE Tunnel | |
+----+-------+ | |Tunnel| +------+----+ |
| +--------+ | +------+ | |
|---+Svc Topo| | +--------+-+--------+
| +--------+ | +----+---+ +---+----+ +-+-----+
| +--------+ | |MPLS-TE | |RSVP-TE | |SR TE |
|---+L2 Topo | | | Tunnel | | Tunnel | |Tunnel |
| +--------+ | +--------+ +--------+ +-------+
| +--------+ |
|---+TE Topo | |
| +--------+ |
| +--------+ |
+---+L3 Topo | |
+--------+ |
Figure 5: Sample Resource Facing Network Models
Topology YANG module Examples:
o Network Topology Models: [RFC8345] defines a base model for
network topology and inventories. Network topology data include
link resource, node resource, and terminate-point resources.
o TE Topology Models: [I.D-ietf-teas-yang-te-topo] defines a data
model for representing and manipulating TE topologies.
This module is extended from network topology model defined in
[RFC8345] with TE topologies specifics. This model contains
technology-agnostic TE Topology building blocks that can be
augmented and used by other technology-specific TE Topology
models.
o L3 Topology Models
[RFC8346] defines a data model for representing and manipulating
L3 Topologies. This model is extended from the network topology
model defined in [RFC8345] with L3 topologies specifics.
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o L2 Topology Models
[I.D-ietf-i2rs-yang-l2-topology] defines a data model for
representing and manipulating L2 Topologies. This model is
extended from the network topology model defined in [RFC8345] with
L2 topologies specifics.
Tunnel YANG module Examples:
o Tunnel identities [I-D.ietf-softwire-iftunnel] to ease
manipulating extensions to specific tunnels.
o TE Tunnel Model
[I.D-ietf-teas-yang-te] defines a YANG module for the
configuration and management of TE interfaces, tunnels and LSPs.
o SR TE Tunnel Model
[I.D-ietf-teas-yang-te] augments the TE generic and MPLS-TE
model(s) and defines a YANG module for Segment Routing (SR) TE
specific data.
o MPLS TE Model
[I.D-ietf-teas-yang-te] augments the TE generic and MPLS-TE
model(s) and defines a YANG module for MPLS TE configurations,
state, RPC and notifications.
o RSVP-TE MPLS Model
[I.D-ietf-teas-yang-rsvp-te] augments the RSVP-TE generic module
with parameters to configure and manage signaling of MPLS RSVP-TE
LSPs.
Other Network Models:
o Path Computation API Model
[I.D-ietf-teas-path-computation] YANG module for a stateless RPC
which complements the stateful solution defined in [I.D-ietf-teas-
yang-te].
o OAM Models (including Fault Management (FM) and Performance
Monitoring)
[RFC8532] defines a base YANG module for the management of OAM
protocols that use Connectionless Communications. [RFC8533]
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defines a retrieval method YANG module for connectionless OAM
protocols. [RFC8531] defines a base YANG module for connection
oriented OAM protocols. These three models are intended to
provide consistent reporting, configuration and representation for
connection-less OAM and Connection oriented OAM separately.
Alarm monitoring is a fundamental part of monitoring the network.
Raw alarms from devices do not always tell the status of the
network services or necessarily point to the root cause. [I.D-
ietf-ccamp-alarm-module] defines a YANG module for alarm
management.
o Generic Policy Model
The Simplified Use of Policy Abstractions (SUPA) policy-based
management framework [RFC8328] defines base YANG modules
[I-D.ietf-supa-generic-policy-data-model]to encode policy. These
models point to device-, technology-, and service-specific YANG
modules developed elsewhere. Policy rules within an operator's
environment can be used to express high-level, possibly network-
wide, policies to a network management function (within a
controller, an orchestrator, or a network element). The network
management function can then control the configuration and/or
monitoring of network elements and services. This document
describes the SUPA basic framework, its elements, and interfaces.
A.3. Device Models: Definitions and Samples
Network Element models (Figure 6) are used to describe how a service
can be implemented by activating and tweaking a set of functions
(enabled in one or multiple devices, or hosted in cloud
infrastructures) that are involved in the service delivery. The
following figure uses IETF defined models as an example.
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+----------------+
--|Device Model |
| +----------------+
| +------------------+
+---------------+ | |Logical Network |
| | --| Element Mode |
| Architecture | | +------------------+
| | | +----------------------+
+-------+-------+ --|Network Instance Mode |
| | +----------------------+
| | +-------------------+
| --|Routing Type Model |
| +-------------------+
+-------+----------+----+------+------------+-----------+-------+
| | | | | | |
+-+-+ +---+---+ +--+------+ +-+-+ +-----+---+ +---+-+ |
|ACL| |Routing| |Transport| |OAM| |Multicast| | PM | Others
+---+ |-------+ +---------+ +---+ +---------+ +-----+
| +-------+ +----------+ +-------+ +-----+ +-----+
--|Core | |MPLS Basic| |BFD | |IGMP | |TWAMP|
| |Routing| +----------+ +-------+ |/MLD | +-----+
| +-------+ |MPLS LDP | |LSP Ping +-----+ |OWAMP|
--|BGP | +----------+ +-------+ |PIM | +-----+
| +-------+ |MPLS Static |MPLS-TP| +-----+ |LMAP |
--|ISIS | +----------+ +-------+ |MVPN | +-----+
| +-------+ +-----+
--|OSPF |
| +-------+
--|RIP |
| +-------+
--|VRRP |
| +-------+
--|SR/SRv6|
| +-------+
--|ISIS-SR|
| +-------+
--|OSPF-SR|
+-------+
Figure 6: Network Element Modules Overview
A.3.1. Model Composition
o Device Model
[I.D-ietf-rtgwg-device-model] presents an approach for organizing
YANG modules in a comprehensive logical structure that may be used
to configure and operate network devices. The structure is itself
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represented as an example YANG module, with all of the related
component models logically organized in a way that is
operationally intuitive, but this model is not expected to be
implemented.
o Logical Network Element Model
[RFC8530] defines a logical network element module which can be
used to manage the logical resource partitioning that may be
present on a network device. Examples of common industry terms
for logical resource partitioning are Logical Systems or Logical
Routers.
o Network Instance Model
[RFC8529] defines a network instance module. This module can be
used to manage the virtual resource partitioning that may be
present on a network device. Examples of common industry terms
for virtual resource partitioning are Virtual Routing and
Forwarding (VRF) instances and Virtual Switch Instances (VSIs).
A.3.1.1. Schema Mount
Modularity and extensibility were among the leading design principles
of the YANG data modeling language. As a result, the same YANG
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
specific use case. [RFC8528] defines a mechanism, denoted schema
mount, that allows for mounting one data model consisting of any
number of YANG modules at a specified location of another (parent)
schema.
That capability does not cover design time.
A.3.2. Device Models: Definitions and Samples
BGP: [I-D.ietf-idr-bgp-yang-model] defines a YANG module for
configuring and managing BGP, including protocol, policy,
and operational aspects based on data center, carrier and
content provider operational requirements.
MPLS: [I-D.ietf-mpls-base-yang] defines a base model for MPLS
which serves as a base framework for configuring and
managing an MPLS switching subsystem. It is expected that
other MPLS technology YANG modules (e.g. MPLS LSP Static,
LDP or RSVP-TE models) will augment the MPLS base YANG
module.
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QoS: [I-D.asechoud-netmod-diffserv-model] describes a YANG
module of Differentiated Services for configuration and
operations.
ACL: Access Control List (ACL) is one of the basic elements
used to configure device forwarding behavior. It is used
in many networking technologies such as Policy Based
Routing, Firewalls, etc. [RFC8519] describes a data model
of Access Control List (ACL) basic building blocks.
NAT: For the sake of network automation and the need for
programming Network Address Translation (NAT) function in
particular, a data model for configuring and managing the
NAT is essential. [RFC8512] defines a YANG module for the
NAT function covering a variety of NAT flavors such as
Network Address Translation from IPv4 to IPv4 (NAT44),
Network Address and Protocol Translation from IPv6 Clients
to IPv4 Servers (NAT64), customer-side translator (CLAT),
Stateless IP/ICMP Translation (SIIT), Explicit Address
Mappings (EAM) for SIIT, IPv6-to-IPv6 Network Prefix
Translation (NPTv6), and Destination NAT. [RFC8513]
specifies a YANG module for the DS-Lite AFTR.
Stateless Address Sharing: [I-D.ietf-softwire-yang] specifies a YANG
module for A+P address sharing, including Lightweight
4over6, Mapping of Address and Port with Encapsulation
(MAP-E), and Mapping of Address and Port using Translation
(MAP-T) softwire mechanisms.
Multicast: [I-D.ietf-pim-yang] defines a YANG module that can be used
to configure and manage Protocol Independent Multicast
(PIM) devices. [I-D.ietf-pim-igmp-mld-yang] defines a
YANG module that can be used to configure and manage
Internet Group Management Protocol (IGMP) and Multicast
Listener Discovery (MLD) devices. [I-D.ietf-pim-igmp-mld-
snooping-yang] defines a YANG module that can be used to
configure and manage Internet Group Management Protocol
(IGMP) and Multicast Listener Discovery (MLD) Snooping
devices.
EVPN: [I-D.ietf-bess-evpn-yang] defines a YANG module for
Ethernet VPN services. The model is agnostic of the
underlay. It apply to MPLS as well as to VxLAN
encapsulation. The model is also agnostic of the services
including E-LAN, E-LINE and E-TREE services. This
document mainly focuses on EVPN and Ethernet-Segment
instance framework.
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L3VPN: [I-D.ietf-bess-l3vpn-yang] defines a YANG module that can
be used to configure and manage BGP L3VPNs [RFC4364]. It
contains VRF specific parameters as well as BGP specific
parameters applicable for L3VPNs.
L2VPN: [I-D.ietf-bess-l2vpn-yang] defines a YANG module for MPLS
based Layer 2 VPN services (L2VPN) [RFC4664] and includes
switching between the local attachment circuits. The
L2VPN model covers point-to-point VPWS and Multipoint VPLS
services. These services use signaling of Pseudowires
across MPLS networks using LDP [RFC8077][RFC4762] or BGP
[RFC4761].
Routing Policy: [I-D.ietf-rtgwg-policy-model] defines a YANG module
for configuring and managing routing policies in a vendor-
neutral way and based on actual operational practice. The
model provides a generic policy framework which can be
augmented with protocol-specific policy configuration.
BFD: [I-D.ietf-bfd-yang]defines a YANG module that can be used
to configure and manage Bidirectional Forwarding Detection
(BFD) [RFC5880]. BFD is a network protocol which is used
for liveness detection of arbitrary paths between systems.
SR/SRv6: [I-D.ietf-spring-sr-yang] a YANG module for segment
routing configuration and operation. [I-D.raza-spring-
srv6-yang] defines a YANG module for Segment Routing IPv6
(SRv6) base. The model serves as a base framework for
configuring and managing an SRv6 subsystem and expected to
be augmented by other SRv6 technology models accordingly.
Core Routing: [RFC8349] defines the core routing data model, which
is intended as a basis for future data model development
covering more-sophisticated routing systems. It is
expected that other Routing technology YANG modules (e.g.,
VRRP, RIP, ISIS, OSPF models) will augment the Core
Routing base YANG module.
PM:
[I.D-ietf-ippm-twamp-yang] defines a data model for client
and server implementations of the Two-Way Active
Measurement Protocol (TWAMP).
[I.D-ietf-ippm-stamp-yang] defines the data model for
implementations of Session-Sender and Session-Reflector
for Simple Two-way Active Measurement Protocol (STAMP)
mode using YANG.
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[RFC8194] defines a data model for Large-Scale Measurement
Platforms (LMAPs).
Authors' Addresses
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Christian
Orange
Rennes 35000
France
Email: christian.jacquenet@orange.com
Luis Miguel Contreras Murillo
Telifonica
Email: luismiguel.contrerasmurillo@telefonica.com
Diego R. Lopez
Telefonica I+D
Spain
Email: diego.r.lopez@telefonica.com
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Chongfeng Xie
China Telecom
Beijing
China
Email: xiechf.bri@chinatelecom.cn
Weiqiang Cheng
China Mobile
Email: chengweiqiang@chinamobile.com
Liang Geng
China Mobile
Email: gengliang@chinamobile.com
Young Lee
Futurewei
Email: younglee.tx@gmail.com
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