Network Working Group                                       L. Andersson
Internet-Draft                                                  Ericsson
Intended status: Informational                           H. van Helvoort
Expires: August 16, November 1, 2010                            Huawei Technologies
                                                               R. Bonica
                                                        Juniper Networks
                                                            D. Romascanu
                                                                   Avaya
                                                            S. Mansfield
                                                                Ericsson
                                                       February 12,
                                                          April 30, 2010

                "The use of the OAM Acronym Soup"
                draft-ietf-opsawg-mpls-tp-oam-def-03.txt in MPLS-TP"
                draft-ietf-opsawg-mpls-tp-oam-def-04.txt

Abstract

   At first glance the acronym "OAM" seems to be well known and well
   understood.  Looking at it the acronym a bit more closely reveals a set
   of recurring problems that are revisited time and again.  This document
   has one primary and one secondary goal.  The primary goal of
   this document is to find an understanding of the OAM acronym that is
   useful for the MPLS Transport Profile (MPLS-TP) effort.  The secondary goal is to make this understanding
   applicable in a wider scope.

   This document is a product of a joint Internet Engineering Task Force
   (IETF) / International Telecommunication Union Telecommunication
   Standardization Sector (ITU-T) effort to include an MPLS Transport
   Profile within the IETF MPLS and PWE3 architectures to support the
   capabilities and functionalities of a packet transport network.

   This Informational Internet-Draft is aimed at achieving IETF
   Consensus before publication as an RFC and will be subject to an IETF
   Last Call.

   [RFC Editor, please remove this note before publication as an RFC and
   insert the correct Streams Boilerplate to indicate that the published
   RFC has IETF Consensus.]

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  OAM and O, A and M . . . . . . . . . . . . . . . . . . . . . .  6
     2.1.  OAM as a functional unit . . . . . . . . . . . . . . . . .  6
     2.2.  The acronym broken up  . . . . . . . . . . . . . . . . . .  6
       2.2.1.  O in OAM . . . . . . . . . . . . . . . . . . . . . . .  6
       2.2.2.  A in OAM . . . . . . . . . . . . . . . . . . . . . . .  6
       2.2.3.  M in OAM . . . . . . . . . . . . . . . . . . . . . . .  7
   3.  Use of the OAM acronym Acronym in the MPLS-TP effort . . . . . . . . . . . .  8
   4.  Acronyms for the MPLS-TP effort  . . . . . . . . . . . . . . . 10
   5.  IANA considerations  . . . . . . . . . . . . . . . . . . . . . 11
   6.  Security considerations  . . . . . . . . . . . . . . . . . . . 12
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 13
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     8.1.  Normative  Informative references . . . . . . . . . . . . . . . . . . . 14
     8.2.  Informative references . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15

1.  Introduction

   The state purpose of this work is very much "work in progress" and the
   discussion is ongoing.  The reason to publish the draft at this stage document is that some of the relevant MPLS-TP drafts are getting close to
   working group last call and some provide a definition of the definitions in this document
   are needed for consistency within OAM
   acronym such that group of drafts. it is useful for MPLS-TP.  The acronym OAM is
   frequently used in the data and telecommunication industry.  One
   would assume that something that is so widely used is very clearly
   defined.  However a closer look reveals some points that need to be
   clarified.

   The examples below come mainly from the first set of MPLS-TP IDs.  In
   the IDs there were show a number of examples of how different ways that the OAM
   acronym could be used expanded and there were a number understood.  The examples come from
   many sources including some of ways to expand and understand the
   acronym e.g.: early MPLS-TP I-Ds.

   o  OAM = Operation, Administration, Maintenance

   o  OAM = Operations, Administration, Maintenance

   o  OAM = Operations, Administration, Management

   o  OAM = Operations and Maintenance

   o  OAM = Operations and Management

   o  O&M = Operations and Maintenance

   o  O&M = Operations and Management

   The examples above were taken from drafts that later were corrected

   o  O&M = OAM and aligned with what is proposed in this document. Management

   Sometimes there is a fourth letter added to the acronym:

   o  OAM and P = Operations, Administration, Maintenance and
      Provisioning

   If such an important piece of our technology is so poorly defined, or
   if there are dialects of the technology with different understandings
   of such a key concept, this will eventually cause problems.

   Trying to understand the use of an acronym that is as "content-rich"
   as OAM reveals two levels of complexity.  First, each letter in the
   acronym represents an integrated piece of functionality; secondly the
   acronym as such represents something that is more than just the sum
   of its parts.

   There is also the issue of how each piece of the acronym is defined.
   This document provides an analysis of how each piece of the acronym
   is defined and provides possible interpretations of the acronym.
   Finally the interpretation of the OAM acronym to use for the MPLS-TP
   effort based on the agreement reached in the JWT (Joint Working Team)
   report [1] is provided.

   The immediate target is to

   Another useful document the use of to make the OAM acronym such
   that it term understandable in a
   wider scope is useful for MPLS-TP.  However, broader applicability of the
   definitions found in this document may also come to light. An Overview of Operations, Administration,
   and Maintenance (OAM) Mechanisms [2].

   This document is a product of a joint Internet Engineering Task Force
   (IETF) / International Telecommunication Union Telecommunication
   Standardization Sector (ITU-T) effort to include an MPLS Transport
   Profile within the IETF MPLS and PWE3 architectures to support the
   capabilities and functionalities of a packet transport network.

2.  OAM and O, A and M

2.1.  OAM as a functional unit

   Operations and And Maintenance (OAM): A group of network management
   functions that provide network fault indication, performance
   information, and data and diagnosis functions.  ATM OAM ITU-T I.610
   [3]
   [4] is an example specification that uses this expansion of the OAM
   acronym.

   Operations, Administration, and Maintenance (OAM): A group of network
   management functions that provide network fault indication, fault
   localization, performance information, and data and diagnosis
   functions.  Examples where this acronym is used are Clause 57 of IEEE
   802.3-2008 [2] [3] and ITU-T Y.1731 [7]. [8].

   The ITU-T M.3010 [6] recommendation [7] Recommendation defines operations systems
   function as a function block that processes information related to
   the telecommunications management for the purpose of monitoring/
   coordinating and/or controlling telecommunication functions including
   management functions (i.e. the TMN (Telecommunications Management
   Network) itself).

   The Metro Ethernet Forum refers to OAM as the tools and utilities to
   install, monitor and troubleshoot a network, helping carriers run
   their networks more efficiently.

2.2.  The acronym broken up

2.2.1.  O in OAM

   The O in the OAM acronym invariably stands for "Operations".

   However there is some ambivalence in the definition and scope of the
   term "Operation".

   Examples of tools related to "operations" are performance monitoring
   tools used for service level agreement (SLA) measurement, fault
   management tools used to monitor the health of nodes and links in the
   network, and network provisioning tools.

2.2.2.  A in OAM

   The A in the OAM acronym mostly stands for "Administration", though
   in a few cases it seems like "Accounting" is also used.  For the
   purpose of this document it is assumed that "Administration" is the
   correct expansion of "A".

   Examples of "administration" tools are network discovery and planning
   tools.

2.2.3.  M in OAM

   In the list above the M in the OAM acronym stands for "Maintenance"
   or "Management".

   Since Maintenance and Management are defined as two different
   activities it does not seem to be a good idea to use them
   interchangeably.  The concept behind OAM is management, so it makes
   more sense to use maintenance as the expansion of the "M" in the
   acronym.

   Examples of "maintenance" tools are implementations of connectivity
   check, loopback, link trace, and other tools that can be used to
   monitor and diagnose failures in a network or network element.

   The recommendation Recommendation ITU-T M.20 [4] [5] defines maintenance as the whole of
   operations required for setting up and maintaining, within prescribed
   limits, any element involved in the setting up of a connection (see
   the ITU-T M.60 [5] recommendation). [6] Recommendation).  The purpose is to properly plan
   and program the maintenance operations required to establish and
   maintain a network.

   A major aim of the concept of maintenance is to minimize both the
   occurrence and the impact of failures and to ensure that in case of a
   failure the correct actions are taken.  The ITU-T documents also
   clearly defines define a maintenance philosophy.

3.  Use of the OAM acronym Acronym in the MPLS-TP effort

   In Section 4 the acronyms as they will be used in the MPLS-TP effort
   are listed.  This section gives some background on the definitions
   provided.

   "Mgt" will be used if an abbreviation for "Management" is needed.
   This draft does not define Management.  It is noted, however, that an
   important part of management functionality relates to tools to report
   the state of the network.

   In MPLS-TP drafts, documents, the OAM acronym is to be used for "Operations,
   Administration and Maintenance", i.e. excluding provisioning.

   OAM tools and protocols and the "Management space" are complementary
   in nature.  Management focuses on FCAPS (Fault, Configuration,
   Accounting, Provisioning, and Security) functionality and on manager
   (or NOC) NOC (Network Operations Center)) to device (or network)
   interaction.

   From an architecture point of view OAM protocols and tools deployed
   in the data plane tend to be "horizontal" i.e. network element to
   network element while the management protocols tend to be "vertical".

   Where each part

   The components of the OAM acronym and provisioning is (and provisioning) are defined as
   follows:

   o  Operations - Operation activities are undertaken to keep the
      network (and the services that the network provides) up and
      running.  It includes monitoring the network and finding problems.
      Ideally these problems should be found before users are affected." affected.

   o  Administration - Administration activities involve keeping track
      of resources in the network and how they are used.  It includes
      all the bookkeeping that is necessary to track networking
      resources and the network under control.

   o  Maintenance - Maintenance activities are focused on facilitating
      repairs and upgrades - for example, when equipment must be
      replaced, when a router needs a patch for an operating system
      image, or when a new switch is added to a network.  Maintenance
      also involves corrective and preventive measures to make the
      managed network run more efficiently, e.g. adjusting device
      configuration and parameters.

   o

   Even though "Provisioning" is not included in this document, the
   following definition is provided for completeness.

   o  Provisioning - Provisioning activities involve configuring
      resources in the network to support the offered services.  This
      might include setting up the network so that a new customer can
      receive an Internet access service.

   o

   In general, Provisioning is used to configure the network for
   providing new services, whereas OAM is used to keep the network in a
   state that it can support already existing services.

   Sometimes it is necessary to talk about the combination of functions
   and tools supplied by OAM and Management, it is preferred that this
   is spelled out as "OAM and Management".  In cases where an acronym is
   needed O&M should be used.

4.  Acronyms for the MPLS-TP effort

   OAM - Operations, Administration and Maintenance

   O&M - Operations, Administration, Maintenance OAM and Management

   "Mgt" - Management

5.  IANA considerations

   This memo includes no request to IANA.

6.  Security considerations

   Security is a significant requirement of MPLS-TP.  However, this
   informational document is intended only to provide guidance on the
   use of the OAM acronym, and the security concerns are, therefore, out
   of scope.

7.  Acknowledgments

   Malcolm Betts from M. C. Betts Consulting Ltd. significantly
   contributed to this document.

8.  References

8.1.  Normative references

8.2.  Informative references

   [1]  Bryant, S. and L. Andersson, "Joint Working Team (JWT) Report on
        MPLS Architectural Considerations for a Transport Profile",
        RFC 5317, February 2009.

   [2]  Mizrahi, T., "An Overview of Operations, Administration, and
        Maintenance (OAM) Mechanisms", draft-ietf-opsawg-oam-overview-00
        (work in progress), January 2010.

   [3]  IEEE, "Information technology - Telecommunications and
        information exchange between systems - Local and metropolitan
        area networks - Specific requirements - Part 3: Carrier sense
        multiple access with collision detection (CSMA/CD) access method
        and physical layer specifications"", IEEE Standard 802.3,
        December 2008.

   [3]

   [4]  International Telecommunication Union, "B-ISDN operation and
        maintenance principles and functions", ITU-T Recommendation
        I.610, February 1999.

   [4]

   [5]  International Telecommunication Union, "Maintenance philosophy
        for telecommunication networks", ITU-T Recommendation M.20,
        October 1992.

   [5]

   [6]  International Telecommunication Union, "Maintenance terminology
        and definitions", ITU-T Recommendation M.60, March 1993.

   [6]

   [7]  International Telecommunication Union, "Principles for a
        telecommunications management network", ITU-T Recommendation
        M.3010, February 2000.

   [7]

   [8]  International Telecommunication Union, "OAM functions and
        mechanisms for Ethernet based networks", ITU-T Recommendation
        Y.1731, February 2008.

Authors' Addresses

   Loa Andersson
   Ericsson

   Email: loa.andersson@ericsson.com

   Huub van Helvoort
   Huawei Technologies

   Email: hhelvoort@huawei.com

   Ron Bonica
   Juniper Networks

   Email: rbonica@juniper.net

   Dan Romascanu
   Avaya

   Email: dromasca@avaya.com

   Scott Mansfield
   Ericsson

   Email: scott.mansfield@ericsson.com