[Docs] [txt|pdf|xml|html] [Tracker] [Email] [Nits]
Versions: 00 01 02 03 04 05
Networking Working Group Q. Wu
Internet-Draft Huawei
Intended status: Standards Track M. Boucadair
Expires: September 4, 2018 Orange
March 3, 2018
An Architecture for Data Model Driven Network Management: the Network
Virtualization Case
draft-wu-model-driven-management-virtualization-00
Abstract
Data Model driven network management can be used at various phases of
service and network management life cycle such as service
instantiation, service provision, optimization, monitoring, and
diagnostic. Also, it can be designed to provide closed-loop control
for the sake of agile service creation, delivery and maintenance.
This document describes an architecture for data model driven network
management with a sample applicability case: network virtualization
environments.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 4, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
Wu & Boucadair Expires September 4, 2018 [Page 1]
Internet-Draft Model Driven Management March 2018
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Architectural Concepts . . . . . . . . . . . . . . . . . . . 4
2.1. Data Models: Layering and Representation . . . . . . . . 4
2.2. Service and Network Resources Exposure: Service Level
Model Decomposition . . . . . . . . . . . . . . . . . . . 4
2.3. Service Element Configuration Model Composition . . . . . 4
2.4. A Catalog for YANG Modules . . . . . . . . . . . . . . . 5
3. IETF YANG Modules: An Overview . . . . . . . . . . . . . . . 5
3.1. Network Service and Resource Models . . . . . . . . . . . 6
3.1.1. Customer facing Service Models: Definition and
Samples . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.2. Resource Facing Network Models . . . . . . . . . . . 7
3.2. Network Element Models . . . . . . . . . . . . . . . . . 9
3.2.1. Model Composition . . . . . . . . . . . . . . . . . . 10
3.2.2. Protocol/Function Configuration Models . . . . . . . 11
4. Architecture Overview . . . . . . . . . . . . . . . . . . . . 12
4.1. End-to-End Service Delivery Procedure . . . . . . . . . . 13
4.1.1. Resource Collection and Abstraction (a) . . . . . . . 13
4.1.2. Service Exposure & Abstraction (b) . . . . . . . . . 14
4.1.3. Model Decomposition/Composition (c) . . . . . . . . . 14
4.1.4. Model Configuration (d) . . . . . . . . . . . . . . . 15
4.1.5. Model Translation (e) . . . . . . . . . . . . . . . . 16
4.1.6. Path Management (f) . . . . . . . . . . . . . . . . . 16
4.1.7. Overlay and Underlay Interaction (g) . . . . . . . . 16
4.1.8. Performance Measurement and Alarm Reporting (h) . . . 17
4.1.9. (Continuous) Network Optimization (i) . . . . . . . . 17
4.2. Overlay and Underlay Interaction Usage: Sample Examples . 17
4.2.1. Network Topology Resource Pre-Provision . . . . . . . 17
4.2.2. On Demand Network Topology Resource Creation . . . . 19
5. Security Considerations . . . . . . . . . . . . . . . . . . . 21
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7. Informative References . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction
As observed in [I-D.arkko-arch-virtualization], many IETF discussions
earlier in the summer of 2017 started from a top-down view of new
virtualization technologies, but were often unable to explain the
Wu & Boucadair Expires September 4, 2018 [Page 2]
Internet-Draft Model Driven Management March 2018
necessary delta to the wealth of existing IETF technologies in this
space. Therefore, [I-D.arkko-arch-virtualization] considered a
bottom-up approach to provide an overview of existing technologies
which is aiming at identifying areas for further development.
For years, the IETF was driving the industry transition from an
overloaded Software Defined Networking (SDN) buzzword to focus on
specific areas such as data modeling-driven management. [RFC7149]
provided a first tentative to rationalize that space by identifying
concrete technical domains that need to be considered:
o Techniques for the dynamic discovery of network 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 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.
Later, as described in [RFC8199], YANG module developers have taken
both top-down and bottom-up approaches to develop modules and
establish mapping between network technology and customer
requirements on the top or abstracting common construct from various
network technologies. At the time of writing this document (2018),
we see the large number of data models including configuration models
and service models developed or under development in IETF covering
much of networking protocols and techniques. In addition, how these
models work together to fully configure a device, or manage a set of
devices involved in a service aren't developed yet in IETF.
This document takes both bottom up approach and top down approach to
provide a framework that discusses the architecture for data model
driven network management, with a focus on network virtualization
environment.
This document also describes specific YANG modules needed to realize
connectivity services and investigate how top down built model (e.g.,
customer-facing data models) interact with bottom up built model
Wu & Boucadair Expires September 4, 2018 [Page 3]
Internet-Draft Model Driven Management March 2018
(resource-facing data models) in the context of service delivery and
assurance.
2. Architectural Concepts
2.1. 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 IETF has developed large number of network level and device level
modules, and few service ones. Service level modules follow top down
approach and are mostly customer-facing models providing a common
model construct for higher level network services, which can be
further mapped to network technology-specific models at lower layer.
Network level modules mostly follow bottom up approach and are mostly
resource-facing model 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 TE Tunnel modules).
Device level modules follow bottom up approach and are mostly
technology-specific modules used to realize a service.
2.2. Service and Network Resources Exposure: Service Level Model
Decomposition
Service level model defines a service ordered by a customer from an
operator. The service can be built from a combination of network
elements and protocols configuration which also include various
aspects of the underlying network infrastructure, including
fucntions/devices and their subsystems, and relevant protocols
operating at the link and network layers across multiple device.
2.3. Service Element Configuration Model Composition
To provide service agility (including network management automation),
lower level technology-specific models need to be assembled together
to provision each involved network function/device and operate the
network based on service requirements described in the service level
model.
IETF RTGWG working group has already been tasked to define service
elements configuration model composition mechanism and develop
several composition model such as network instance model, logical
network element model and device model.
Wu & Boucadair Expires September 4, 2018 [Page 4]
Internet-Draft Model Driven Management March 2018
These models can be used to setup and administrate both virtualized
system and physical system.
2.4. A Catalog for YANG Modules
The idea of a catalog is similar to service catalogs in traditional
IT environments. Service catalogs serve as a software-based
registries of available services with information needed to discover
and invoke available services.
The IETF has already tasked to develop a YANG catalog which can be
used to manage not only IETF defined modules, but also non-IETF
defined ones [I-D.clacla-netmod-model-catalog].
The YANG catalog allows to align IETF work with other SDOs work and
prevent duplicated building blocks being developed. It also
encourages reusability of common building blocks.
The YANG catalog allows both YANG developers and operators to
discover the more mature YANG modules that may be used to automate
services operations .
3. IETF YANG Modules: An Overview
Wu & Boucadair Expires September 4, 2018 [Page 5]
Internet-Draft Model Driven Management March 2018
<< Customer facing Service Models>>
+-------------+ +-------------+
+----------------+ +----------------+ |DOTS Data | | I2NSF |
| L3SM | | L2SM | |and Signaling| | Customer |
| Service Model | | Service Model | | Models | | Facing Model|
+----------------+ +----------------+ +-------------+ +-------------+
-------------------------------------------------------------------
<< Resource Facing Models>>
+------------+ +-------+ +----------------+ +------------+
|Network Topo| | Tunnel| |Path Computation| |OAM,PM,Alarm|
| Models | | Models| | API Models | | Models |
+------------+ +-------+ +----------------+ +------------+
<<Network Service and Resource Models>>
--------------------------------------------------------------------
<<Network Element Models>>
<<Composition Models>>
+-------------+ +---------------+ +----------------+
|Device Model | |Logical Network| |Network Instance|
| | |Element Model | | Model |
+-------------+ +---------------+ +----------------+
----------------------------------------------------------------------
<< Component Models>>
+------------+
+-----+ +------+ +---++----+ +----+ |OAM,PM,Alarm|
| BGP | | MPLS | |ACL||QoS | |NAT | | Models | .....
+-----+ +------+ +---++----+ +----+ +------------+
3.1. Network Service and Resource Models
Service and Network Resource Exposure modules define what the
"service"/"resource" is. These modules can be classified into two
categories:
o Customer-facing Models
o Resource-facing Models
3.1.1. Customer facing Service Models: Definition and Samples
As described in [RFC8309], the 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.
For example,
o L3SM model defines the L3VPN service ordered by a the customer
from a network operator.
Wu & Boucadair Expires September 4, 2018 [Page 6]
Internet-Draft Model Driven Management March 2018
o L2SM model defines the L2VPN service ordered by a the customer
from a network operator.
The IETF is currently defining three other customer-facing modules:
ietf-dots-signal-channel [I-D.ietf-dots-signal-channel] and ietf-
dots-data-channel [I-D.ietf-dots-data-channel] and I2NSF Consumer-
Facing Interface YANG module
[I-D.jeong-i2nsf-consumer-facing-interface-dm]. The first two
modules are meant to be used by clients to signal DDoS attacks or to
request installing filters for the sake of DDoS mitigation. Those
modules do not intervene directly in the configuration of underlying
network devices. The third module is required for enabling different
users of a given I2NSF system to define, manage, and monitor security
policies for specific flows within an administrative domain.
3.1.2. Resource Facing Network Models
Figure 1 shows a set of resource-facing network YANG modules:
| |
Topo YANG Models | Tunnel Service Models |Resource NM Tool
------------------------------------------------|-- ------------
+------------+ | |
|Network Top | | +-----------+ | +-------+
| Model | | | TE Tunnel | | | LIME |
+----+-------+ | +------+----+ | | Model |
| +--------+ | | | |/PM/OAM|
|---+TE Topo | | +--------+-+--------+ | Model|
| +--------+ | +----+---+ +---+----+ +-+-----+ +-------+
| +--------+ | |MPLS-TE | |RSVP-TE | |SR TE | +--------+
+---+L3 Topo | | Tunnel | | Tunnel | |Tunnel | | Alarm |
+----|---+ +--------+ +--------+ +-------+ | Model |
+---------+---------+ +--------+
| | | +-----------+
+---|---+ +--|---+ +---|-+ |Path |
|SR Topo| |SR TE | |L3 TE| |Computation|
| Model | | Topo | |Topo | |API Model |
+-------+ +------+ +-----+ +-----------+
Figure 1: Sample Resource Facing Network Models
o Network Topology Models: [I.D-ietf-i2rs-yang-network-topo] defines
base model for network topology and inventories. Network topology
data include link resource, node resource and terminate-point
resource.
o TE Topology Models: [I.D-ietf-teas-yang-te-topo] defines a data
model for representing and manipulating TE Topologies.
Wu & Boucadair Expires September 4, 2018 [Page 7]
Internet-Draft Model Driven Management March 2018
This module is extended from network topology model defined in
[I.D-ietf-i2rs-yang-network-topo] 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
[I.D-ietf-i2rs-yang-l3-topology] defines a data model for
representing and manipulating L3 Topologies. This model is
extended from the network topology model defined in [I.D-ietf-
i2rs-yang-network-topo] with L3 topologies specifics.
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 [I.D-ietf-
i2rs-yang-network-topo] with L2 topologies specifics.
o L3 TE Topology Models
When traffic engineering is enabled on a layer 3 network topology,
there will be a corresponding TE topology. [I.D-liu-teas-yang-l3-
te-topo] defines data models for layer 3 traffic engineering
topologies. Two data models are defined, one is layer 3 TE
topology model, the other is packet switching TE topology model.
Layer 3 TE topology model is extended from Layer 3 topology model.
Packet switching TE topology model is extended from TE topology
model.
o SR TE Topology Models
[I-D.liu-teas-yang-sr-te-topo] defines a YANG module for Segment
Routing (SR) topology and Segment Routing (SR) traffic engineering
(TE) topology. Two models are defined, one is SR topology model,
the other is SR TE topology model, SR topology model is extended
from L3 Topology model. SR TE topology model is extended from
both SR Topology model and L3 TE topology model.
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
Wu & Boucadair Expires September 4, 2018 [Page 8]
Internet-Draft Model Driven Management March 2018
[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.
o Path Computation API Model
[I.D-ietf-teas-path-computation] yang model for a stateless RPC
which complements the stateful solution defined in [I.D-ietf-teas-
yang-te].
o OAM Models
[I.D-ietf-lime-yang-connectionless-oam] defines a base YANG module
for the management of OAM protocols that use Connectionless
Communications. [I.D-ietf-lime-yang-connectionless-oam-methods]
defines a retrieval method YANG module for connectionless OAM
protocols. [I.D-ietf-lime-yang-connection-oriented-oam-model]
defines a base YANG module for connection oriented OAM protocols.
These three models can be used to provide consistent reporting,
configuration and representation.
o PM Models
o Alarm Models
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.
3.2. Network Element Models
Network Element models are used to describe how a service can be
implemented by activating and tweaking a set of functions (enabled in
one or multiple devices) that are involved in the service delivery.
Wu & Boucadair Expires September 4, 2018 [Page 9]
Internet-Draft Model Driven Management March 2018
+----------------+
--|Device Model |
| +----------------+
| +------------------+
+---------------+ | |Logical Network |
| | --| Element Mode |
| Architecture | | +------------------+
| | | +----------------------+
+-------+-------+ --|Network Instance Mode |
| | +----------------------+
| | +-------------------+
| --|Routing Type Model |
| +-------------------+
+-------+----------+----+------+------------+-----------+-------+
| | | | | | |
+-+-+ +---+---+ +--+-+ +-+-+ +-----+---+ +---+-+ |
|ACL| |Routing| |MPLS| |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 |
| +-------+
--|ISIS-SR|
| +-------+
--|OSPF-SR|
| +-------+
3.2.1. Model Composition
o Device Model
[I.D-ietf-rtgwg-device-model] presents an approach for organizing
YANG models in a comprehensive logical structure that may be used
to configure and operate network devices.The structure is itself
represented as an example YANG model, 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.
Wu & Boucadair Expires September 4, 2018 [Page 10]
Internet-Draft Model Driven Management March 2018
o Logical Network Element Model
[I.D-ietf-rtgwg-lne-model] 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
[I.D-ietf-rtgwg-ni-model] 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).
3.2.1.1. 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. [I-D.ietf-netmod-schema-mount] 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.
3.2.2. Protocol/Function Configuration Models
BGP: [I.D-mks-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 models (e.g. MPLS LSP Static,
LDP or RSVP-TE models) will augment the MPLS base YANG
model.
QoS: [I.D-asechoud-netmod-diffserv-model] describes a YANG
model of Differentiated Services for configuration and
operations.
Wu & Boucadair Expires September 4, 2018 [Page 11]
Internet-Draft Model Driven Management March 2018
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. [I.D-ietf-netmod-acl-model]
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. [I.D-ietf-opsawg-nat-yang] defines a
YANG module for the NAT function.
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.
4. Architecture Overview
The architectural considerations and conclusions described in the
previous section lead to the architecture described in this section
and illustrated in Figure 2.
The interfaces and interactions shown in the figure and labeled (a)
through (j) are further described in Section 5.1.
Wu & Boucadair Expires September 4, 2018 [Page 12]
Internet-Draft Model Driven Management March 2018
+-----------------+
|Service Requester|
+-^--|------------+
+-------|--|------------------------------------------------------+
| | (b)+---(h)------ feedback |
| | V | |
| +--|----V+ +-------------+ |
| |Service&| | Model |-----(c)-----------------+ |
| +-->Resource|->Decomposition| | |
| | |Exposure| |/Composition | | |
| | +--------+ +-------------+ | |
| | | | |
| | +------V-----+ +-----------+ +------V------+ |
| | | Model | (e) | Path | (f) | Model | |
| | | Translation|--------->|Computation|------->|Configuration| |
| | +------------+ +-^---------+ +-----(d)-----+ |
| (a)Exposure&Abstraction | | | |
| | --------------------+ |(f) V |
| | | | |
| | +----|------+ +------V----+ |
| | |Basic Topo | | Path | |
| +--|Collection | +---| Setup | |
| +----^--|---+ | +-----------+ |
| | | | (h) |
| (a) | +------V----+Service +-----------+ (i) |
| | | | Topo | Topo | PM/Alarm | Network Opt |
| | +--> Mapping -------> | Collection------> |
| | +-----------+ +-----------+ |
+--------------------(g)------------------------------------------+
Figure 2: Data Model Driven Management
4.1. End-to-End Service Delivery Procedure
4.1.1. Resource Collection and Abstraction (a)
Network Resource such as links, nodes, or terminate-point resources
can be collected from the network and aggregated or abstracted to the
management system.
These resources can be modelled using network topology model, L3
topology model, L2 topology model, TE topology model, L3 TE topology
model, SR TE topology models at different layers.
In some cases, there may have multiple overlay topologies built on
top of the same underlay topology, and the underlay topology can be
also built from one or more lower layer underlay topology.
Wu & Boucadair Expires September 4, 2018 [Page 13]
Internet-Draft Model Driven Management March 2018
The network resources and management objects are exposed in a more
abstract way to the management system or customers who (will) order
the service from the management system.
The abstract view is likely to be technology-agnostic.
4.1.2. Service Exposure & Abstraction (b)
Service exposure & abstraction is used to capture services offered to
customers.
Service abstraction can be used by a customer to request a service
(ordering and order handling). One typical example is that a
customer can use L3SM service model to request L3VPN service by
providing the abstract technical characterization of the intended
service. Such L3VPN service describes various aspects of network
infrastructure, including devices and their subsystems, and relevant
protocols operating at the link and network layers across multiple
device. The L3SM service model can be used to interact with the
network infrastructure, e.g., configure sites, decide QoS parameters
to be applied to each network access within a site, select PEs, CEs,
etc.
Service catalogs can be created to expose the various services and
the information needed to invoke/order a given service.
YANG modules can be grouped into various service bundles; each
service bundle is corresponding to a set of YANG modules that have
been released or published. Then, a mapping can be established
between service abstraction and service bundles at higher layer and
between service bundle and a set of YANG modules at lower layer.
4.1.3. Model Decomposition/Composition (c)
Service abstraction starts with high-level abstractions exposing the
business capabilities or capturing customer requirements. Then, it
needs to maps them to resource abstraction and specific network
technologies.
Therefore, the interaction between service abstraction and resource
abstraction or between overlay and underlay is required. For
example, in the L3SM service model, we describe VPN service topology
including sites relationship, e.g., hub and spoke and any to any,
single homed, dual-homed, multi-homed relation between PEs and CEs,
but we don't know how this service topology can be mapped into
underlying network topology. For detailed interaction, please refer
to . (Section 4.1.7)
Wu & Boucadair Expires September 4, 2018 [Page 14]
Internet-Draft Model Driven Management March 2018
In addition, there is a need to decide on a mapping between service
abstraction and underlying specific network technologies. Take L3SM
service model as an example, to realize L3VPN service, we need to map
L3SM service view defined in Service model into detailed
configuration view defined by specific configuration models for
network elements, these configuration models include:
o VRF definition, including VPN Policy expression
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
These detailed configuration models are further assembled together
into service bundle using, e.g., device model, logical network
element model or network instance model defined in [I.D-ietf-rtgwg-
device-model] [I.D-ietf-rtgwg-lne-model] [I.D-ietf-rtgwg-ni-model]
provide the association between an interface and its associated LNE
and NI and populate into appropriate devices(e.g., PE and CE).
4.1.4. Model Configuration (d)
Model Configuration is used to provision service or network
infrastructure using various configuration models, e.g., use service
element models such as BGP, ACL, QoS, Interface model, Network
instance models to configure PE and CE device within the site. BGP
Policy model is used to establish VPN membership between sites and
VPN Service Topology. Traditionally, "push" service element
configuration model one by one to the network device and provide
association between an interface and each service element
configuration model is not efficient.
To automate configuration of the service elements, we first assemble
all related service elements models into logical network element
model defined in [I.D-ietf-rtgwg-lne-model] and then establish
association with an interface and a set of service elements.
Wu & Boucadair Expires September 4, 2018 [Page 15]
Internet-Draft Model Driven Management March 2018
In addition, Model configuration can be used to setup tunnels between
sites and setup tunnels between PE and CE within the site when
tunnels related configuration parameters can be generated from
service abstraction.
4.1.5. Model Translation (e)
In L3SM Service Model, the management system will have to determine
where to connect each site-network-access of a particular site to the
provider network (e.g., PE, aggregation switch). L3SM Service model
proposes parameters and constraints that can influence the meshing of
the site-network-access.
Nodes used to connect a site may be captured in relevant clauses of a
service exposure model (e.g., Customer Nodes Map [RFC7297]).
When Site location is determined, PE and CE device location will be
selected. Then we can replace parameters and constraints that can
influence the meshing of the site-network-access with specified PE
and CE device information associated with site- network-access and
generate resource facing VN Overlay Resource model.
This VN Overlay Resource model can be used to calculate node and link
resource to Meet service requirements based on Network Topology
models collected at step (a).
4.1.6. Path Management (f)
Path Management includes Path computation and Path setup. For
example, we can translate L3SM service model into resource facing VN
Overlay Resource Model, with selected PE and CE in each site, we can
calculate point to point or multipoint end to end path between sites
based on VPN Overlay Resource Model.
4.1.7. Overlay and Underlay Interaction (g)
After identifying node and link resources required to meet service
requirements, the mapping between overlay topology and underlay
topology can be set, e.g., establish an association between VPN
service topology defined in customer facing model and underlying
network topology defined in I2RS network topology model (e.g., one
overlay node is supported by multiple underlay nodes, one overlay
link is supported by multiple underlay nodes)and generate end to end
VN topology model.
Wu & Boucadair Expires September 4, 2018 [Page 16]
Internet-Draft Model Driven Management March 2018
4.1.8. Performance Measurement and Alarm Reporting (h)
Once the mapping between overlay and underlay has been setup, PM and
Warning information per link based on end to end VN topology can be
collected and report to the management system.
Performance metrics can be collected before instantiating a service,
too.
4.1.9. (Continuous) Network Optimization (i)
Operators may use dedicated features to dynamically capture the
overall network status and topology to:
o Perform all the requested recovery operations upon detecting
network failures affecting the network service.
o Adjust resource distribution and update to end to end Service
topology models
o Provide resource scheduling to better guarantee services for
customers and to improve the efficiency of network resource usage.
4.2. Overlay and Underlay Interaction Usage: Sample Examples
4.2.1. Network Topology Resource Pre-Provision
Wu & Boucadair Expires September 4, 2018 [Page 17]
Internet-Draft Model Driven Management March 2018
|(2)
|
V
+-------------------+
| Management System | (3)(4)(5)
+-------------------+
+--------------------------------------------------------+
/ _[CE2] _[CE3] /
/ _/ : \_ _/ : \_ /
/ _/ : \_ _/ : \_ /
/ _/ : \_ _/ : \_ /
/ / : \ / : \ /
/[CE1]_________________[PE1] [PE2]_________________[CE4] /
+---------:--------------:------------:--------------:---+
"Service"
--------------------------------------------------------------------
+---------------------+ +---------------------+"Resource"
/ [Y5]... / / [Z5]______[Z3] /
/ / \ : / / : \_ / : /
/ / \ : / / : \_ / : /
/ / \ : / / : \ / : /
/ [Y4]____[Y1] : / / : [Z2] : /
+------:-------:---:--+ +---:---------:-----:-+ ^
vNet1 : : : : : : vNet2 |
: : : : : : |(1)
: +-------:---:-----:------------:-----:-----+ |
: / [X1]__:___:___________[X2] : / |
:/ / \_ : : _____/ / : / |
: / \_ : _____/ / : /
/: / \: / / : /
/ : / [X5] / : /
/ : / __/ \__ / : /
/ : / ___/ \__ / : /
/ : / ___/ \ / : /
/ [X4]__________________[X3]..: /
+------------------------------------------+
L3 Topology
The following steps are performed to deliver the service within model
driven management architecture proposed in this document:
o Pre-provision multiple (virtualized) overlay networks on top of
the same basic network infrastructure and establish resource pool
for each overlay network.
o Request to create two sites based on L3SM Service model with each
having one network access connectivity:
Wu & Boucadair Expires September 4, 2018 [Page 18]
Internet-Draft Model Driven Management March 2018
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
o Select appropriate virtualized overlay networks topology based on
Service Type and service requirements defined in L3SM service
model.
o Translate L3SM service model into resource facing VN Network
Model, based on selected virtualized overlay network topology and
PE and CE info in the generated resource facing VN network model,
calculate node resource, link resource corresponding to
connectivity between sites or connectivity between PE and CE
within a Site.
o Setup tunnels between sites and tunnels between PE and CE within a
Site and map them into the selected (virtualized) overlay topology
and establish resource facing VN topology model.
The source facing VN topology model and corresponding Tunnel model
can be used to notify all the parameter changes and event related
to VN topology or Tunnel. These information can be further used
to adjust network resource distributing in the network.
4.2.2. On Demand Network Topology Resource Creation
Wu & Boucadair Expires September 4, 2018 [Page 19]
Internet-Draft Model Driven Management March 2018
|(2)
|
V
+-------------------+
| Management System | (3)(4)(5)
+-------------------+
+--------------------------------------------------------+
/ _[CE2] _[CE3] /
/ _/ : \_ _/ : \_ /
/ _/ : \_ _/ : \_ /
/ _/ : \_ _/ : \_ /
/ / : \ / : \ /
/[CE1]_________________[PE1] [PE2]_________________[CE4] /
+---------:--------------:------------:--------------:---+
"Service"
--------------------------------------------------------------------
"Resource" ^
: |
: : : |(1)
: +-------:---:-----:------------:-----:-----+ |
: / [X1]__:___ __________[X2] / |
:/ / \_ : _____/ / / |
: / \_ : _____/ / /
/: / \: / / /
/ : / [X5] / /
/ : / __/ \__ / /
/ : / ___/ \__ / /
/ : / ___/ \ / /
/ [X4]__________________[X3]. /
+------------------------------------------+
L3 Topology
The following steps are performed to deliver the service within model
driven management architecture proposed in this document:
o Establish resources pool for basic network infrastructure.
o Request 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
Wu & Boucadair Expires September 4, 2018 [Page 20]
Internet-Draft Model Driven Management March 2018
o Create a new service topology based on Service Type and service
requirements (e.g., Slice Service Type, Slice location, Number of
Slices, QoS requirements corresponding to network connectivity
within a Slice) defined in L3SM service model.
o Translate L3SM service model into resource facing VN Network
Model, based on generated resource facing VN network model,
calculate node resource, link resource corresponding to
connectivity between sites or connectivity between PE and CE
within Site in the service topology.
o Setup tunnels between sites and tunnel between PE and CE within
Site and map them into basic network infrastructure and establish
resource facing VN topology model. The source facing VN topology
model and corresponding Tunnel model can be used to notify all the
parameter changes and event related to VN topology or Tunnel.
These information can be further used to adjust network resource
distribution within the network.
5. 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
6. IANA Considerations
There are no IANA requests or assignments included in this document.
7. 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-00 (work in progress),
November 2017.
Wu & Boucadair Expires September 4, 2018 [Page 21]
Internet-Draft Model Driven Management 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-02
(work in progress), October 2017.
[I-D.ietf-ccamp-alarm-module]
Vallin, S. and M. Bjorklund, "YANG Alarm Module", draft-
ietf-ccamp-alarm-module-01 (work in progress), February
2018.
[I-D.ietf-dots-data-channel]
Reddy, T., Boucadair, M., Nishizuka, K., Xia, L., Patil,
P., Mortensen, A., and N. Teague, "Distributed Denial-of-
Service Open Threat Signaling (DOTS) Data Channel
Specification", draft-ietf-dots-data-channel-13 (work in
progress), January 2018.
[I-D.ietf-dots-signal-channel]
Reddy, T., 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-17 (work in progress), January
2018.
[I-D.ietf-i2rs-yang-l3-topology]
Clemm, A., Medved, J., Varga, R., Liu, X.,
Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model
for Layer 3 Topologies", draft-ietf-i2rs-yang-
l3-topology-16 (work in progress), December 2017.
[I-D.ietf-i2rs-yang-network-topo]
Clemm, A., Medved, J., Varga, R., Bahadur, N.,
Ananthakrishnan, H., and X. Liu, "A Data Model for Network
Topologies", draft-ietf-i2rs-yang-network-topo-20 (work in
progress), December 2017.
[I-D.ietf-l2sm-l2vpn-service-model]
Wen, B., Fioccola, G., Xie, C., and L. Jalil, "A YANG Data
Model for L2VPN Service Delivery", draft-ietf-l2sm-l2vpn-
service-model-08 (work in progress), February 2018.
Wu & Boucadair Expires September 4, 2018 [Page 22]
Internet-Draft Model Driven Management March 2018
[I-D.ietf-lime-yang-connection-oriented-oam-model]
Kumar, D., Wu, Q., and Z. Wang, "Generic YANG Data Model
for Connection Oriented Operations, Administration, and
Maintenance(OAM) protocols", draft-ietf-lime-yang-
connection-oriented-oam-model-07 (work in progress),
February 2018.
[I-D.ietf-lime-yang-connectionless-oam]
Kumar, D., Wang, Z., Wu, Q., Rahman, R., and S. Raghavan,
"Generic YANG Data Model for the Management of Operations,
Administration, and Maintenance (OAM) Protocols that use
Connectionless Communications", draft-ietf-lime-yang-
connectionless-oam-18 (work in progress), November 2017.
[I-D.ietf-lime-yang-connectionless-oam-methods]
Kumar, D., Wang, Z., Wu, Q., Rahman, R., and S. Raghavan,
"Retrieval Methods YANG Data Model for the Management of
Operations, Administration, and Maintenance (OAM)
Protocols that use Connectionless Communications", draft-
ietf-lime-yang-connectionless-oam-methods-13 (work in
progress), November 2017.
[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-06 (work in progress), February 2018.
[I-D.ietf-netmod-acl-model]
Jethanandani, M., Huang, L., Agarwal, S., and D. Blair,
"Network Access Control List (ACL) YANG Data Model",
draft-ietf-netmod-acl-model-16 (work in progress),
February 2018.
[I-D.ietf-netmod-schema-mount]
Bjorklund, M. and L. Lhotka, "YANG Schema Mount", draft-
ietf-netmod-schema-mount-08 (work in progress), October
2017.
[I-D.ietf-opsawg-nat-yang]
Boucadair, M., Sivakumar, S., Jacquenet, C., Vinapamula,
S., and Q. Wu, "A YANG Module for Network Address
Translation (NAT) and Network Prefix Translation (NPT)",
draft-ietf-opsawg-nat-yang-13 (work in progress), February
2018.
Wu & Boucadair Expires September 4, 2018 [Page 23]
Internet-Draft Model Driven Management March 2018
[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-06 (work in progress),
October 2017.
[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-15 (work in
progress), February 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-lne-model]
Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
Liu, "YANG Model for Logical Network Elements", draft-
ietf-rtgwg-lne-model-09 (work in progress), March 2018.
[I-D.ietf-rtgwg-ni-model]
Berger, L., Hopps, C., Lindem, A., Bogdanovic, D., and X.
Liu, "YANG Model for Network Instances", draft-ietf-rtgwg-
ni-model-11 (work in progress), March 2018.
[I-D.ietf-teas-yang-path-computation]
Busi, I., Belotti, S., Lopezalvarez, V., Dios, O.,
ansharma@infinera.com, a., Shi, Y., Vilata, R.,
Sethuraman, K., Scharf, M., and D. Ceccarelli, "Yang model
for requesting Path Computation", draft-ietf-teas-yang-
path-computation-00 (work in progress), November 2017.
[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", draft-ietf-
teas-yang-rsvp-te-03 (work in progress), February 2018.
[I-D.ietf-teas-yang-te]
Saad, T., Gandhi, R., Liu, X., Beeram, V., Shah, H., and
I. Bryskin, "A YANG Data Model for Traffic Engineering
Tunnels and Interfaces", draft-ietf-teas-yang-te-12 (work
in progress), February 2018.
Wu & Boucadair Expires September 4, 2018 [Page 24]
Internet-Draft Model Driven Management March 2018
[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-15 (work in
progress), February 2018.
[I-D.jeong-i2nsf-consumer-facing-interface-dm]
Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares,
"I2NSF Consumer-Facing Interface YANG Data Model", draft-
jeong-i2nsf-consumer-facing-interface-dm-05 (work in
progress), November 2017.
[I-D.liu-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-liu-teas-yang-l3-te-topo-05 (work in progress),
October 2017.
[I-D.liu-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-liu-teas-yang-sr-te-topo-04 (work in
progress), October 2017.
[I-D.mks-idr-bgp-yang-model]
Patel, K., Jethanandani, M., and S. Hares, "BGP YANG
Model", draft-mks-idr-bgp-yang-model-01 (work in
progress), November 2017.
[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>.
[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>.
[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>.
Wu & Boucadair Expires September 4, 2018 [Page 25]
Internet-Draft Model Driven Management March 2018
[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>.
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
Wu & Boucadair Expires September 4, 2018 [Page 26]
Html markup produced by rfcmarkup 1.129c, available from
https://tools.ietf.org/tools/rfcmarkup/