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Versions: (draft-zhou-supa-framework) 00 01 02 draft-ietf-supa-policy-based-management-framework

SUPA                                                            W. Liu
Internet Draft                                            J. Strassner
Intended status: Informational                          G. Karagiannis
Expires: January 2017                              Huawei Technologies
                                                              M. Klyus
                                                            NetCracker
                                                                 J. Bi
                                                   Tsinghua University
                                                                C. Xie
                                                         China Telecom
                                                         July 22, 2016

                  SUPA policy-based management framework
          draft-liu-supa-policy-based-management-framework-02


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
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   http://datatracker.ietf.org/drafts/current/.

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   reference material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 8, 2016.

Copyright Notice

   Copyright (c) 2016 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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   (http://trustee.ietf.org/license-info) in effect on the date of
   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
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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.

Table of Contents


   1. Introduction ................................................ 2
   2. Framework for Generic Policy-based Management ............... 3
      2.1. Overview ............................................... 3
      2.2. Operation .............................................. 8
      2.3. The GPIM and the EPRIM ................................. 9
      2.4. Creation of Generic YANG Modules ....................... 9
   3. Security Considerations .................................... 10
   4. IANA Considerations ........................................ 10
   5. Contributors ............................................... 10
   6. Acknowledgments ............................................ 10
   7. References ................................................. 12
      7.1. Normative References .................................. 12
      7.2. 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 and 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) [SUPA-info-model] for use in network
   operations and management applications. The GPIM defines concepts
   and terminology needed by policy management indepednent of the form
   and content of the policy rule. The ECA Policy Rule Information
   Model (EPRIM) [SUPA-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. Framework for Generic Policy-based Management

   This section briefly describes the design and operation of the SUPA
   policy-based management framework.

2.1. Overview

   Figure 1 shows a simplified functional architecture of how SUPA is
   used to define policies for creating network element configuration
   and monitoring snippets. 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, as well as the combination of the
   GPIM and EPRIM, are converted to generic YANG data modules.




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   In one possible approach, SUPA Generic & 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.


                       +---------------------+
   +----------+       \|        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

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   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. Imperative policy rules require
   additional management functions, which are explained in section 2.2
   below.

   Figure 2 shows a SUPA Policy Model creating and communicating policy
   rules to two different Network Manager and  Network Controller
   elements.

   The Generic Policy Information Model (GPIM) was used to construct
   policies. The GPIM defines generic policy concepts, as well as two
   types of policies: ECA policy rules and declarative policy
   statements.

   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.

   A set of Generic Policy Data Models 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.




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                         OSS/BSS/Orchestrator
                                 / \
                                  C
                                 \ /
   +------------------------------+----------------------------------+
   |                       SUPA Policy Model                         |
   |              +----------------------------------+               |
   |              | Generic Policy Information Model |               |
   |              +----+------------------------+----+               |
   |                   D                       \D/                   |
   |                   D           +------------+--------------+     |
   |                   D           | ECAPolicyRule Information |     |
   |                   D           | Model (EPRIM)             |     |
   |                   D           +------------+--------------+     |
   |  +----------------D------------------------D----------------+   |
   |  |               \D/   SUPA Policy DM      D                |   |
   |  |+---------------+-----------+            D                |   |
   |  || Generic Policy Data Model |            D                |   |
   |  |+-------------------+-------+            D                |   |
   |  |                   \D/                  \D/               |   |
   |  |                 +--+--------------------+--------------+ |   |
   |  |                 |    ECA PolicyRule Data Model         | |   |
   |  |                 +--------------------------------------+ |   |
   |  +------------------------------+---------------------------+   |
   +---------------------------------|-------------------------------+
                       +-------------+--------+
                      \C/                    \C/  NETCONF/RESTCONF
      +----------------+-----------+  +-------+--------------------+
      |      EMS/NMS/Controller    |  |      EMS/NMS/Controller    |
      |   +---------------------+  |  |   +---------------------+  |
      |   |  Network Service &  |  |  |   |  Network Service &  |  |
      |   | Resource Data Models|  |  |   | Resource Data Models|  |
      |   +---------------------+  |  |   +---------------------+  |
      +---+---+---+----------------+  +-----+---+---+--------------+
         / \ / \ / \                       / \ / \ / \
          C   C   C                         C   C   C
         \ / \ / \ /                       \ / \ / \ /
         NE1 NE2 NEn                       NE1 NE2 NEn

                   Figure 2 SUPA Policy Model Framework


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   In Figure 2:
   A double-headed arrow with Cs means communication;
   A double-headed arrow with Ds means derived from.

   The network elements used in 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, and 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 for that are
   dependent of data repository, data definition, query, and
   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, 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 & 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.




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   Relationship among Policy, Service and Resource models can be illustrated by the
   figure below.
      +---------------+                   +----------------+
      |    Policy     |         (1)       |    Service     |
      |               |*******************|                |
      |   ( SUPA )    |                   | ( L3SM, ... )  |
      +---------------+                   +----------------+
             **                                    **
               **                                **
                 **                            **
              (2)  **                        **   (3)
                     **                    **
                       **                **
                         **            **
                     +-------------------+
                     |    Resource       |
                     |                   |
                     | (Inventory, ... ) |
                     +-------------------+
          Figure 3 Relationship among Policy, Service and Resource

   In Figure 3:
   (1) policy manages and can adjust service behavior as necessary
   (2) policy manages and can adjust resource behavior as necessary
   (3) resource hosts service; changing resources may change service
   behavior as necessary

   Policies are used to manage behavior. Policies can be applied to
   services and resources. 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.


2.2. 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.

   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 achieve but not how
   to achieve those goals (also called "intent-based" policies) are out
   of scope for the initial phase of SUPA.




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2.3. 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.

   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.

   The SUPA working group develops models for expressing policy at
   different levels of abstraction. Specifically, two models are
   envisioned (both of which are contained in the Generic Policy
   Information Model block in Figure 1:

   1. a generic model (the GPIM) that defines concepts and vocabulary
      needed by policy management systems independent of the form and
      content of the policy

   2. a more specific model (the EPRIM) that refines the GPIM to
      specify policy rules in an event-condition-action form

2.4. 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, as well as 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.

   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


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   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 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.


3. Security Considerations

   TBD

4. IANA Considerations

   This document has no actions for IANA.

5. 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

6. Acknowledgments

   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, 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" [Klyus2016]

   The following people all contributed to creating this document,
   listed in alphabetical order:


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         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" [Klyus2016] 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)"   [Karagiannis2015]

   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 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)"   [Karagiannis2015] were:








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         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)"
   [Zhou2015]

   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.

   Early version of this draft can be found here:
   https://tools.ietf.org/html/draft-zhou-supa-architecture-00
   At the early stage of SUPA, we think quite some issues are left open,
   it is not so suitable to call this draft as "architecture". We would
   like to rename it to "framework". Later there may be a dedicated
   architecture document.

   The authors of "The Framework of Simplified Use of Policy
   Abstractions (SUPA)" [Zhou2015] were:

         Cathy Zhou, Huawei Technologies
         Luis M. Contreras, Telefonica
         Qiong Sun, China Telecom
         Parviz Yegani, Juniper


7. References

7.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

7.2. Informative References

   [RFC3198] Westerinen, A., Schnizlein, J., Strassner, J.,
   Scherling, M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry,
   J., Waldbusser, S., "Terminology for Policy-Based Management", RFC
   3198, November, 2001


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   [RFC6020] M. Bjorklund, "YANG - A Data Modeling Language for the
   Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.

   [RFC6020bis] M. Bjorklund, "The YANG 1.1 Data Modeling Language",
   IETF Internet draft, draft-ietf-netmod-rfc6020bis-14, June 2016.

   [RFC7285] R. Alimi, R. Penno, Y. Yang, S. Kiesel, S. Previdi, W.
   Roome, S. Shalunov, R. Woundy "Application-Layer Traffic
   Optimization (ALTO) Protocol", September 2014

   [SUPA-info-model] J. Strassner, J. Halpern, S. van der Meer, "Generic
   Policy Information Model for Simplified Use of Policy Abstractions
   (SUPA)", IETF Internet draft,
   draft-ietf-supa-generic-policy-info-model-01, July 2016

   [TR235] J. Strassner, ed., "ZOOM Policy Architecture and
   Information Model Snapshot", TR245, part of the TM Forum ZOOM
   project, October 26, 2014

   [Karagiannis2015] G. Karagiannis, ed., "Problem Statement for
   Simplified Use of Policy Abstractions (SUPA)", IETF Internet draft,
   draft-karagiannis-supa-problem-statement-07, June 5, 2015

   [Klyus2016] M. Klyus, ed., "SUPA Value Proposition", IETF Internet
   draft, draft-klyus-supa-value-proposition-00, Mar 21, 2016

   [Zhou2015] C. Zhou, ed., "The Framework of Simplified Use of Policy
   Abstractions (SUPA)", draft-zhou-supa-framework-02, May 08, 2015























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Authors' Addresses

   Will(Shucheng) Liu
   Huawei Technologies
   Bantian, Longgang District, Shenzhen 518129
   P.R. China
   Email: liushucheng@huawei.com

   John Strassner
   Huawei Technologies
   2330 Central Expressway
   Santa Clara, CA 95138 USA
   Email: strazpdj@gmail.com

   Georgios Karagiannis
   Huawei Technologies
   Hansaallee 205, 40549 Dusseldorf
   Germany
   Email: Georgios.Karagiannis@huawei.com

   Maxim Klyus
   NetCracker
   Kozhevnicheskaya str.,7 Bldg. #1
   Moscow, Russia
   E-mail: klyus@netcracker.com

   Jun Bi
   Tsinghua University
   Network Research Center, Tsinghua University
   Beijing  100084
   P.R. China
   Email: junbi@tsinghua.edu.cn

   Chongfeng Xie
   China Telecom Beijing Research Institute
   China Telecom Beijing Information Science&Technology Innovation Park
   Beiqijia Town Changping District Beijing 102209 China
   Email: xiechf@ctbri.com.cn


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