Subject: [secdir] [new-work] WG Review: Simplified Use of Policy Abstractions (supa)

From: The IESG <[email-masked]>
Date: Fri, 18 Sep 2015 08:14:00 -0700

A new IETF working group has been proposed in the Operations and
Management Area. The IESG has not made any determination yet. The
following draft charter was submitted, and is provided for informational
purposes only. Please send your comments to the IESG mailing list (iesg
at ietf.org) by 2015-09-28.

Simplified Use of Policy Abstractions (supa)
------------------------------------------------
Current Status: Proposed WG

Assigned Area Director:
  Benoit Claise <[email-masked]>

Mailing list
  Address: [email-masked]
  To Subscribe: https://www.ietf.org/mailman/listinfo/supa
  Archive: https://mailarchive.ietf.org/arch/browse/supa/

Charter:

Policies are a set of rules that define how services are designed,
delivered, and operated within an operator's networking environment. As
such, policies play a critical role in the automated service delivery and
operational procedures. Operators want and need to be able to define the
policies that apply to their different customers and to the equipment
that comprises their physical and virtual networks. Policies usually span
a wide range of services that are supported by various technologies:
thus, a common way for expressing and describing policies that is uniform
and consistent regardless of the nature of the networking environment is
likely to facilitate the overall service delivery procedure and
operation. Such an approach will minimize the risk of configuration
errors that arise from confusion between different systems, will enable
easy understanding of policies that apply in different environments, will
make the implementation of policy-based systems quicker and cheaper, and
will facilitate the rapid development of standards-based data models that
include policy elements.

The SUPA (Simplified Use of Policy Abstractions) working group defines a
data model, to be used to represent high-level, possibly network-wide
policies, which can be input to a network management function (within a
controller, an orchestrator, or a network element). Processing that input
most probably results in network configuration changes. SUPA however does
not deal with the definition of the specific network configuration
changes but with how the configuration changes are applied (e.g. who is
allowed to set policies, when and how the policies are activated, changed
or de-activated).
 
Practically, 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.

SUPA focuses on a single management domain, and is designed to work with
device, protocol, network, and service data models. 

The working group will have succeeded when the SUPA policy constructs are
re-used in future IETF specifications (and ideally specifications from
other SDOs), in a matter that saves development time and avoid
inconsistencies between data models developed by different working
groups. In the mean time, other working groups should not delay their
deliverables waiting for SUPA to complete its work.

The SUPA working group develops models for expressing policy at different
levels of abstraction.  Specifically, two models are envisioned: 
(i) a generic model that defines concepts and vocabulary needed by policy
management independent of the form and content of the policy
(ii) a more specific model that refines the generic model to specify how
to build policy rules of the event-condition-action paradigm

If the working group finds it necessary to work on an information model
before the data model, to help provide guidance and derive the data
models, it may do so. The working group will decide later whether the
information model needs to be published as an RFC.

Out of scope of this working group are:  
-   The specification of a new policy protocol or a new data modelling
language. 
-   Design of protocol-specific policies and specific design for embedded
policies in network elements (which are usually interpreted in isolation,
and often at timescales that require optimization for specific purposes).
-   Specific handling of policies (although the application document will
provide some examples). Therefore the specification of a policy engine
that maps a specific policy instance to actual configuration snippets is
also out of scope.

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 but may be considered in future
phases of SUPA.

List of work items:
1) An explanation of the scope of the policy-based management framework
and how it relates to existing work of the IETF.

2) If the working group considers it necessary, a generic information
model composed of policy concepts and vocabulary. 

3) A set of YANG data models consisting of a base policy model for
representing policy management concepts independent of the type or
structure of a policy, plus an extension for defining policy rules
according to the event-condition-action paradigm. 

4) An applicability document providing a few examples that demonstrate
how the YANG policy data models can be used to express policies that are
relevant for network operators. The examples may tie into configuration
models or network service models developed by other working groups.

The working group will decide how the work items are best mapped into
deliverables.

The working group will communicate with other SDOs (MEF, TMF, ETSI) that
are working on related issues.

Milestones:
Apr 2016 Submit the policy-based management framework (Informational)
Apr 2016 Submit the generic information model (Informational)
Jun 2016 Submit the set of YANG data models (Standards Track)
Aug 2016 Submit the applicability document (Informational)
Aug 2016 Re-charter or close

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