Service Models Explained
RFC 8309

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Internet Engineering Task Force (IETF)                             Q. Wu
Request for Comments: 8309                                        W. Liu
Category: Informational                              Huawei Technologies
ISSN: 2070-1721                                                A. Farrel
                                                        Juniper Networks
                                                            January 2018

                        Service Models Explained

Abstract

   The IETF has produced many modules in the YANG modeling language.
   The majority of these modules are used to construct data models to
   model devices or monolithic functions.

   A small number of YANG modules have been defined to model services
   (for example, the Layer 3 Virtual Private Network Service Model
   (L3SM) produced by the L3SM working group and documented in RFC
   8049).

   This document describes service models as used within the IETF and
   also shows where a service model might fit into a software-defined
   networking architecture.  Note that service models do not make any
   assumption of how a service is actually engineered and delivered for
   a customer; details of how network protocols and devices are
   engineered to deliver a service are captured in other modules that
   are not exposed through the interface between the customer and the
   provider.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8309.

Wu, et al.                    Informational                     [Page 1]
RFC 8309                Service Models Explained            January 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
   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terms and Concepts  . . . . . . . . . . . . . . . . . . . . .   4
   3.  Using Service Models  . . . . . . . . . . . . . . . . . . . .   7
     3.1.  Practical Considerations  . . . . . . . . . . . . . . . .   8
   4.  Service Models in an SDN Context  . . . . . . . . . . . . . .   8
   5.  Possible Causes of Confusion  . . . . . . . . . . . . . . . .  11
   6.  Comparison with Other Work  . . . . . . . . . . . . . . . . .  13
     6.1.  Comparison with Network Service Models  . . . . . . . . .  13
     6.2.  Service Delivery and Network Element Model Work . . . . .  15
     6.3.  Customer Service Model Work . . . . . . . . . . . . . . .  16
     6.4.  The MEF Architecture  . . . . . . . . . . . . . . . . . .  17
   7.  Further Concepts  . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  Technology Agnostic . . . . . . . . . . . . . . . . . . .  18
     7.2.  Relationship to Policy  . . . . . . . . . . . . . . . . .  18
     7.3.  Operator-Specific Features  . . . . . . . . . . . . . . .  19
     7.4.  Supporting Multiple Services  . . . . . . . . . . . . . .  19
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  20
   9.  Manageability Considerations  . . . . . . . . . . . . . . . .  20
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  21
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  21
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  21
     11.2.  Informative References . . . . . . . . . . . . . . . . .  21
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  23
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

Wu, et al.                    Informational                     [Page 2]
RFC 8309                Service Models Explained            January 2018

1.  Introduction

   In recent years, the number of modules written in the YANG modeling
   language [RFC6020] for configuration and monitoring has blossomed.