Network Working Group L. Andersson
Internet-Draft Ericsson
Intended status: Informational H. van Helvoort
Expires: August 16, 2010 Huawei Technologies
R. Bonica
Juniper Networks
D. Romascanu
Avaya
S. Mansfield
Ericsson
February 12, 2010
"The OAM Acronym Soup"
draft-ietf-opsawg-mpls-tp-oam-def-03.txt
Abstract
At first glance the acronym "OAM" seems to be well known and well
understood. Looking at it 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 is to find
an understanding of OAM 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.]
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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Task Force (IETF), its areas, and its working groups. Note that
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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 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 references . . . . . . . . . . . . . . . . . . . 14
8.2. Informative references . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
The state of this work is very much "work in progress" and the
discussion is ongoing. The reason to publish the draft at this stage
is that some of the relevant MPLS-TP drafts are getting close to
working group last call and some of the definitions in this document
are needed for consistency within that group of drafts.
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 a number of examples of how the OAM acronym could
be used and there were a number of ways to expand and understand the
acronym e.g.:
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
and aligned with what is proposed in this document.
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
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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 report [1] is
provided.
The immediate target is to document the use of the OAM acronym such
that it is useful for MPLS-TP. However, broader applicability of the
definitions in this document may also come to light.
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.
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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
[3] 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] and ITU-T Y.1731 [7].
The ITU-T M.3010 [6] 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 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
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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 ITU-T M.20 [4] 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). 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 a maintenance philosophy.
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3. Use of the OAM acronym 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, 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 functionality and on manager
(or NOC) to device (or network) interaction.
From an architecture point of view OAM protocols and tools tend to be
"horizontal" i.e. network element to network element while the
management protocols tend to be "vertical".
Where each part of the acronym and provisioning is 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."
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.
Provisioning - Provisioning activities involve configuring
resources in the network to support the offered services. This
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might include setting up the network so that a new customer can
receive an Internet access service.
o 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.
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4. Acronyms for the MPLS-TP effort
OAM - Operations, Administration and Maintenance
O&M - Operations, Administration, Maintenance and Management
"Mgt" - Management
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5. IANA considerations
This memo includes no request to IANA.
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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.
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7. Acknowledgments
Malcolm Betts from M. C. Betts Consulting Ltd. significantly
contributed to this document.
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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] 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] International Telecommunication Union, "B-ISDN operation and
maintenance principles and functions", ITU-T Recommendation
I.610, February 1999.
[4] International Telecommunication Union, "Maintenance philosophy
for telecommunication networks", ITU-T Recommendation M.20,
October 1992.
[5] International Telecommunication Union, "Maintenance terminology
and definitions", ITU-T Recommendation M.60, March 1993.
[6] International Telecommunication Union, "Principles for a
telecommunications management network", ITU-T Recommendation
M.3010, February 2000.
[7] International Telecommunication Union, "OAM functions and
mechanisms for Ethernet based networks", ITU-T Recommendation
Y.1731, February 2008.
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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
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