Network Working Group                                       L. Andersson
Internet-Draft                                                  Ericsson
Intended status: Informational                           H. van Helvoort
Expires: November 1, 7, 2010                            Huawei Technologies
                                                               R. Bonica
                                                        Juniper Networks
                                                            D. Romascanu
                                                            S. Mansfield
                                                          April 30,
                                                             May 6, 2010

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


   At first glance the acronym "OAM" seems to be well known and well
   understood.  Looking at the acronym a bit more closely reveals a set
   of recurring problems that are revisited time and again.

   The immediate goal of this document is to find an understanding of
   the OAM acronym that is useful for MPLS.  This document is
   specifically applicable to the new OAM functionality developed for
   the MPLS Transport Profile (MPLS-TP) effort. project.  However, broader
   applicability of the definitions in this document may also come to
   light, e.g. the intention is to use these definitions for all future
   IETF documents.

   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.]

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

   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 November 1, 7, 2010.

Copyright Notice

   Copyright (c) 2010 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
   ( 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 . . . . . . . . . . . . . . . . . . . . . . . . .  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 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.  Informative references . . . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15

1.  Introduction

   The main purpose of this document is to provide a definition of the
   OAM acronym such that it is useful for MPLS-TP. MPLS.  However, the
   information in this document is not specific to MPLS, so broader
   applicability of the OAM definitions provided is appropriate.  It is
   understood that all future IETF documents will use these definitions
   when appropriate.

   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 show a number of different ways that the OAM
   acronym could be expanded and understood.  The examples come from
   many sources including some of the 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

   o  O&M = OAM and Management

   Sometimes there is a fourth letter added to the acronym:

   o  OAM and P = Operations, Administration, Maintenance and

   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.

   Another useful document to make the OAM term understandable in a
   wider scope is found in 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 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
   [4] is an example specification that uses this expansion of the OAM

   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 [3] and ITU-T Y.1731 [8].

   The ITU-T M.3010 [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

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

   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 ITU-T M.20 [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 [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 define a maintenance philosophy.

3.  Use of the OAM 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

   "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 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 (Network Operations Center)) to device (or network)

   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".

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

   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.

   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.

   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.

   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 - 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.  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.

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

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

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

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

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

Authors' Addresses

   Loa Andersson


   Huub van Helvoort
   Huawei Technologies


   Ron Bonica
   Juniper Networks


   Dan Romascanu


   Scott Mansfield