Network Working Group W. Liu
Internet-Draft Huawei Technologies
Intended status: Informational C. Xie
Expires: September 14, 2017 China Telecom Beijing Research Institute
J. Strassner
G. Karagiannis
Huawei Technologies
M. Klyus
NetCracker
J. Bi
Tsinghua University
March 13, 2017
SUPA Policy-based Management Framework
draft-ietf-supa-policy-based-management-framework-01
Abstract
Simplified Use of Policy Abstractions (SUPA) defines base YANG data
models to encode policy, which will point to device-, technology-,
and service-specific YANG models developed in other working groups.
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.
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 http://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 14, 2017.
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Copyright Notice
Copyright (c) 2017 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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Framework for Generic Policy-based Management . . . . . . . . 4
3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Operation . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. The GPIM and the EPRIM . . . . . . . . . . . . . . . . . 9
3.4. Creation of Generic YANG Modules . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
The rapid growth in the variety and importance of traffic flowing
over increasingly complex enterprise and service provider network
architectures makes the task of network operations and management
applications deploying new services much more difficult. In
addition, network operators want to deploy new services quickly and
efficiently. Two possible mechanisms for dealing with this growing
difficulty are the use of software abstractions to simplify the
design and configuration of monitoring and control operations, and
the use of programmatic control over the configuration and operation
of such networks. Policy-based management can be used to combine
these two mechanisms into an extensible framework.
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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.
Simplified Use of Policy Abstractions (SUPA) will define a generic
policy information model (GPIM) [I-D.ietf-supa-generic-policy-info-
model] for use in network operations and management applications.
The GPIM defines concepts and terminology needed by policy management
independent of the form and content of the policy rule. The ECA
Policy Rule Information Model (EPRIM) [I-D.ietf-supa-generic-policy-
info-model] extends the GPIM to define how to build policy rules
according to the event-condition-action paradigm.
Both the GPIM and the EPRIM are targeted at controlling the
configuration and monitoring of network elements throughout the
service development and deployment lifecycle. The GPIM and the EPRIM
will both be translated into corresponding YANG [RFC6020][RFC6020bis]
modules that define policy concepts, terminology, and rules in a
generic and interoperable manner; additional YANG modules may also be
defined from the GPIM and/or EPRIM to manage specific functions.
The key benefit of policy management is that it enables different
network elements and services to be instructed to behave the same
way, even if they are programmed differently. Management
applications will benefit from using policy rules that enable
scalable and consistent programmatic control over the configuration
and monitoring of network elements and services.
2. Terminology
GPIM: Generic Policy Information Model, which defines concepts and
terminology needed by policy management independent of the form and
content of the policy rule.
EPRIM: ECA Policy Rule Information Model, which extends the GPIM to
define how to build policy rules according to the event-condition-
action paradigm.
GPDM: Generic Policy Data Models [I-D.ietf-supa-generic-policy-data-
model], are created from the GPIM. These YANG data model policies
are used to control the configuration of network elements that model
the service(s) to be managed using policy.
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3. Framework for Generic Policy-based Management
This section briefly describes the design and operation of the SUPA
policy-based management framework.
3.1. Overview
Figure 1 shows a simplified functional architecture of how SUPA is
used to define policies for creating network element configuration
snippets. (Note from Editor: a "snippet" is a small piece of
information (e.g., part of a sentence that was cut out).) SUPA uses
the GPIM to define a consensual vocabulary that different actors can
use to interact with network elements and services. The EPRIM
defines a generic structure for imperative policies. The GPIM, and/
or the combination of the GPIM and the EPRIM, is converted to generic
YANG data modules.
In one possible approach, SUPA Generic Policy and SUPA ECA Policy
YANG data modules together with the Resource and Service YANG data
models specified in IETF (which define the specific elements that
will be controlled by policies) are used by the Service Interface
Logic. This Service Interface Logic creates appropriate input
mechanisms for the operator to define policies (e.g., a web form or a
script) for creating and managing the network configuration. The
operator interacts with the interface, which is then translated to
configuration snippets.
Note that YANG models may not exist. In this case, the SUPA generic
policy YANG data modules serve as an extensible basis to develop new
YANG data models for the Service Interface Logic to create
appropriate input mechanisms for the operator to define policies.
This transfers the work specified by the Resource and Service YANG
data models specified in IETF into the Service Interface Logic, which
is then translated to configuration snippets.
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+---------------------+
+----------+ \| SUPA |
| IETF |---+----+ Information Models |
+----------+ | /| GPIM and EPRIM |
| +---------+-----------+
Assignments | | Defines Policy Concepts
and Manage | \|/
Content | +---------+-----------+
| \| SUPA Generic |
+----+ & ECA Policy |
/| YANG Data modules |
+---------+-----------+
* Possible Approach
+-----------------------------*-----------------------------+
| Management System * |
| \*/ |
| Fills +---------+---------+ +-------------+ |
| +--------+ Forms \| Service Interface |/ |Resource and |/ | +----+
| |Operator|--------+ Logic +--|Service YANG |----|IETF|
| +--------+ Runs /| (locally defined |\ | Data Models |\ | +----+
| scripts |forms, scripts,...)| +-------------+ |
| +---------+---------+ |
| \|/ |
| +-------+--------+ |
| | Local Devices | |
| | and Management | |
| | Systems | |
| +----------------+ |
+-----------------------------------------------------------+
Figure 1: SUPA Framework
Figure 1 is exemplary. The Operator actor shown in Figure 1 can
interact with SUPA in other ways not shown in Figure 1. In addition,
other actors (e.g., an application developer) that can interact with
SUPA are not shown for simplicity.
The EPRIM defines an Event-Condition-Action (ECA) policy as an
example of imperative policies. An ECA policy rule is activated when
its event clause is true; the condition clause is then evaluated and,
if true, signals the execution of one or more actions in the action
clause. This type of policy explicitly defines the current and
desired states of the system being managed. Imperative policy rules
require additional management functions, which are explained in
section 2.2 below.
Figure 2 shows how the SUPA Policy Model is used to create policy
data models step by step and how the policy rules are used to
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communicate among various network management functions located on
different layers.
The Generic Policy Information Model (GPIM) is used to construct
policies. The GPIM defines generic policy concepts, as well as two
types of policies: ECA policy rules and declarative policy
statements.
A set of Generic Policy Data Models (GPDM) are then created from the
GPIM. These YANG data model policies are then used to control the
configuration of network elements that model the service(s) to be
managed using policy.
SUPA designed YANG data models can be the input for management
functions, and automatically generate interfaces and data stores.
During the run time, components communicate with the data instances
for management and monitoring.
+
| SUPA Policy Model
|
| +----------------------------------+
| | Generic Policy Information Model |
| +----------------------------------+
| D D
| D +-------------v-------------+
+----------------------+ | D | ECAPolicyRule Information |
| OSS/BSS/Orchestrator <--+ | D | Model |
+----------^-----------+ | | D +---------------------------+
C | | D D
C | | +----+D+------------------------+D+---+
C +-----+ D SUPA Policy Data Model D |
+----------v-----------+ | | ----v-----------------------+ D |
| EMS/NMS/Controller <--------+ | Generic Policy Data Model | D |
+----------^-----------+ | | ----------------------------+ D |
C +-----+ D D |
C | | | +--------v-----------------v--+ |
+----------v-----------+ | | | | ECA PolicyRule Data Model | |
| Network Element <--+ | | +-----------------------------+ |
+----------------------+ | +-------------------------------------+
|
|
Figure 2: SUPA Policy Model Framework
In Figure 2:
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The double-headed arrow with Cs means communication;
The arrow with Ds means derived from.
The components within this framework are:
SUPA Policy Model: represents one or more policy modules that contain
the following entities:
Generic Policy Information Model: a model for defining policy rules
that are independent of data repository, data definition, query,
implementation languages, and protocol. This model is abstract and
is used for design; it MUST be turned into a data model for
implementation.
Generic Policy Data Model: a model of policy rules that are dependent
on data repository, data definition, query, implementation languages,
and protocol.
ECA Policy Rule Information Data Model (EPRIM): represents a policy
rule as a statement that consists of an event clause, a condition
clause, and an action clause. This type of Policy Rule explicitly
defines the current and desired states of the system being managed.
This model is abstract and is used for design; it MUST be turned into
a data model for implementation.
ECA Policy Rule Data Model: a model of policy rules, derived from
EPRIM, that consist of an event clause, a condition clause, and an
action clause.
EMS/NMS/Controller: represents one or more entities that are able to
control the operation and management of a network infrastructure
(e.g., a network topology that consists of Network Elements).
Network Service and Resource Data Models: models of the service as
well as physical and virtual network topology including the resource
attributes (e.g., data rate or latency of links) and operational
parameters needed to support service deployment over the network
topology.
Network Element (NE), which can interact with local or remote
EMS/NMS/Controller in order to exchange information, such as
configuration information, policy enforcement capabilities, and
network status.
Relationship between Policy, Service and Resource models can be
illustrated by the figure below.
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+---------------+ +----------------+
| Policy | (1) | Service |
| |*******************| |
| ( SUPA ) |*******************| ( L3SM, ... ) |
+---------------+ +----------------+
** /*\
** *
** *
(2) ** * (3)
** *
** *
** *
+-------------------+
| Resource |
| |
| (Inventory, ... ) |
+-------------------+
Figure 3: Relationship between Policy, Service and Resource models
In Figure 3:
(1) policy manages and can adjust service behavior as necessary
(1:1..n)
(2) policy manages and can adjust resource behavior as necessary
(1:1..n)
(3) resource hosts service; changing resources may change service
behavior as necessary
Policies are used to control the management of resources and
services, while data from resources and services are used to select
and/or modify policies during runtime. More importantly, policies
can be used to manage how resources are allocated and assigned to
services. This enables a single policy to manage one or multiple
services and resources as well as their dependencies. (1:1..n) in (1)
and (2) below figure 3 shows one policy rule is able to manages and
can adjust one or multiple services/resources. Line (1) and (2)
connecting policy to resource and policy to service are same, and
line (3) connecting resource to service is different as it's
navigable only from resource to service.
3.2. Operation
SUPA can be used to define various types of policies, including
policies that affect services and/or the configuration of individual
or groups of network elements. SUPA can be used by a centralized
and/or distributed set of entities for creating, managing,
interacting with, and retiring policy rules.
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The SUPA scope is limited to policy information and data models.
SUPA will not define network resource data models or network service
data models; both are out of scope. Instead, SUPA will make use of
network resource data models defined by other WGs or SDOs.
Declarative policies that specify the goals to be achieved but not
how to achieve those goals (also called "intent-based" policies) are
out of scope for the initial phase of SUPA.
3.3. The GPIM and the EPRIM
The GPIM provides a common vocabulary for representing concepts that
are common to expressing different types of policy, but which are
independent of language, protocol, repository, and level of
abstraction. Hence, the GPIM defines concepts and vocabulary needed
by policy management systems independent of the form and content of
the policy. The ERPIM is a more specific model that refines the GPIM
to specify policy rules in an event-condition-action form.
This enables different policies at different levels of abstraction to
form a continuum, where more abstract policies can be translated into
more concrete policies, and vice-versa. For example, the information
model can be extended by generalizing concepts from an existing data
model into the GPIM; the GPIM extensions can then be used by other
data models.
3.4. Creation of Generic YANG Modules
An information model is abstract. As such, it cannot be directly
instantiated (i.e., objects cannot be created directly from it).
Therefore, both the GPIM and the combination of the GPIM and the
EPRIM, are translated to generic YANG modules.
SUPA will provide guidelines for translating the GPIM (or the
combination of the GPIM and the EPRIM) into concrete YANG data models
that define how to manage and communicate policies between systems.
Multiple imperative policy YANG data models may be instantiated from
the GPIM (or the combination of the GPIM and the EPRIM). In
particular, SUPA will specify a set of YANG data models that will
consist of a base policy model for representing policy management
concepts independent of the type or structure of a policy, and as
well, an extension for defining policy rules according to the ECA
paradigm.(Note from Editor: This means that policies can be defined
using the GPIM directly, or using the combination of the GPIM and the
EPRIM. If you use only the GPIM, you get a technology- and vendor-
independent information model that you are free to map to the data
model of your choice; note that the structure of a policy is NOT
defined. If you use the GPIM and the EPRIM, you get a technology-
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and vendor-independent information model that defines policies as an
event-condition-action (i.e., imperative) rule.)
The process of developing the GPIM, EPRIM and the derived/translated
YANG data models is realized following the sequence shown below.
After completing this process and if the implementation of the YANG
data models requires it, the GPIM and EPRIM and the derived/
translated YANG data models are updated and synchronized.
(1)=>(2)=>(3)=>(4)=>(3')=>(2')=>(1')
Where, (1)=GPIM; (2)=EPRIM; (3)=YANG data models; (4)=
Implementation; (3')= update of YANG data models; (2')=update of
EPRIM; (1') = update of GPIM
The YANG module derived from the GPIM contains concepts and
terminology for the common operation and administration of policy-
based systems, as well as an extensible structure for policy rules of
different paradigms. The YANG module derived from the EPRIM extends
the generic nature of the GPIM to represent policies using an event-
condition-action structure.
The above sequence allows for the addition of new, as well as the
editing of existing model elements in the GPIM and EPRIM. In
practice, the implementation sequence may be much simpler.
Specifically, it is unlikely that the GPIM will need to be changed.
In addition, changes to the EPRIM will likely be focused on fine-
tuning the behavior offered by a specific set of model elements.
4. Security Considerations
TBD
5. IANA Considerations
This document has no actions for IANA.
6. Contributors
The following people all contributed to creating this document,
listed in alphabetical order:
Ying Chen, China Unicom
Luis M. Contreras, Telefonica I+D
Dan Romascanu, Avaya
J. Schoenwaelder, Jacobs University, Germany
Qiong Sun, China Telecom
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7. Acknowledgements
This document has benefited from reviews, suggestions, comments and
proposed text provided by the following members, listed in
alphabetical order: Andy Bierman, Benoit Claise, Joel Halpern,
Jonathan Hansford, Bert Wijnen, Tianran Zhou.
Part of the initial draft of this document was picked up from
previous documents, and this section lists the acknowledgements from
them.
From "SUPA Value Proposition" [I-D.klyus-supa-value-proposition]
The following people all contributed to creating this document,
listed in alphabetical order:
Vikram Choudhary, Huawei Technologies
Luis M. Contreras, Telefonica I+D
Dan Romascanu, Avaya
J. Schoenwaelder, Jacobs University, Germany
Qiong Sun, China Telecom
Parviz Yegani, Juniper Networks
This document has benefited from reviews, suggestions, comments and
proposed text provided by the following members, listed in
alphabetical order: H. Rafiee, J. Saperia and C. Zhou.
The authors of "SUPA Value Proposition" [I-D.klyus-supa-value-
proposition] were:
Maxim Klyus, Ed. , NetCracker
John Strassner, Ed. , Huawei Technologies
Will(Shucheng) Liu, Huawei Technologies
Georgios Karagiannis, Huawei Technologies
Jun Bi, Tsinghua University
The initial draft of this document merged one document, and this
section lists the acknowledgements from it.
From "Problem Statement for Simplified Use of Policy Abstractions
(SUPA)" [I-D.karagiannis-supa-problem-statement]
The authors of this draft would like to thank the following persons
for the provided valuable feedback and contributions: Diego Lopez,
Spencer Dawkins, Jun Bi, Xing Li, Chongfeng Xie, Benoit Claise, Ian
Farrer, Marc Blancet, Zhen Cao, Hosnieh Rafiee, Mehmet Ersue, Simon
Perreault, Fernando Gont, Jose Saldana, Tom Taylor, Kostas
Pentikousis, Juergen Schoenwaelder, John Strassner, Eric Voit, Scott
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O. Bradner, Marco Liebsch, Scott Cadzow, Marie-Jose Montpetit. Tina
Tsou, Will Liu and Jean-Francois Tremblay contributed to an early
version of this draft.
The authors of "Problem Statement for Simplified Use of Policy
Abstractions (SUPA)" [I-D.karagiannis-supa-problem-statement] were:
Georgios Karagiannis, Huawei Technologies
Qiong Sun, China Telecom
Luis M. Contreras, Telefonica
Parviz Yegani, Juniper
John Strassner, Huawei Technologies
Jun Bi, Tsinghua University
From "The Framework of Simplified Use of Policy Abstractions (SUPA)"
[I-D.zhou-supa-framework]
The authors of this draft would like to thank the following persons
for the provided valuable feedback: Diego Lopez, Jose Saldana,
Spencer Dawkins, Jun Bi, Xing Li, Chongfeng Xie, Benoit Claise, Ian
Farrer, Marc Blancet, Zhen Cao, Hosnieh Rafiee, Mehmet Ersue, Mohamed
Boucadair, Jean Francois Tremblay, Tom Taylor, Tina Tsou, Georgios
Karagiannis, John Strassner, Raghav Rao, Jing Huang.
The authors of "The Framework of Simplified Use of Policy
Abstractions (SUPA)" [I-D.zhou-supa-framework] were:
Cathy Zhou, Huawei Technologies
Luis M. Contreras, Telefonica
Qiong Sun, China Telecom
Parviz Yegani, Juniper
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
8.2. Informative References
[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-02 (work in progress),
October 2016.
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[I-D.ietf-supa-generic-policy-info-model]
Strassner, J., Halpern, J., and S. Meer, "Generic Policy
Information Model for Simplified Use of Policy
Abstractions (SUPA)", draft-ietf-supa-generic-policy-info-
model-02 (work in progress), January 2017.
[I-D.karagiannis-supa-problem-statement]
Karagiannis, G., Strassner, J., Qiong, Q., Contreras, L.,
Yegani, P., and J. Bi, "Problem Statement for Simplified
Use of Policy Abstractions (SUPA)", draft-karagiannis-
supa-problem-statement-07 (work in progress), June 2015.
[I-D.klyus-supa-value-proposition]
Klyus, M., Strassner, J., (Will), S., Karagiannis, G., and
J. Bi, "SUPA Value Proposition", draft-klyus-supa-value-
proposition-00 (work in progress), March 2016.
[I-D.zhou-supa-framework]
Zhou, C., Contreras, L., Qiong, Q., and P. Yegani, "The
Framework of Simplified Use of Policy Abstractions
(SUPA)", draft-zhou-supa-framework-02 (work in progress),
May 2015.
[RFC3198] Westerinen, A., Schnizlein, J., Strassner, J., Scherling,
M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry,
J., and S. Waldbusser, "Terminology for Policy-Based
Management", RFC 3198, DOI 10.17487/RFC3198, November
2001, <http://www.rfc-editor.org/info/rfc3198>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<http://www.rfc-editor.org/info/rfc6020>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<http://www.rfc-editor.org/info/rfc7285>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<http://www.rfc-editor.org/info/rfc7950>.
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Authors' Addresses
Will(Shucheng) Liu
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
P.R. China
Email: liushucheng@huawei.com
Chongfeng Xie
China Telecom Beijing Research Institute
China Telecom Information Technology Innovation Park
Beijing 102209
P.R. China
Email: xiechf.bri@chinatelecom.cn
John Strassner
Huawei Technologies
2330 Central Expressway
Santa Clara 95138
CA USA
Email: john.sc.strassner@huawei.com
Georgios Karagiannis
Huawei Technologies
Hansaallee 205
Dusseldorf 40549
Germany
Email: Georgios.Karagiannis@huawei.com
Maxim Klyus
NetCracker
Kozhevnicheskaya str.,7 Bldg. #1
Moscow
Russia
Email: klyus@netcracker.com
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Jun Bi
Tsinghua University
Network Research Center, Tsinghua University
Beijing 100084
P.R. China
Email: junbi@tsinghua.edu.cn
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