| Network Working Group | L. Andersson |
| Internet-Draft | Ericsson |
| Intended status: Best Current Practice | H. van Helvoort |
| Expires: October 08, 2011 | Huawei Technologies |
| R. Bonica | |
| Juniper Networks | |
| D. Romascanu | |
| Avaya | |
| S. Mansfield | |
| Ericsson | |
| April 06, 2011 |
"Guidelines for the use of the OAM acronym in the IETF"
draft-ietf-opsawg-mpls-tp-oam-def-09.txt
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.
This document provides a definition of the acronym OAM (Operations, Administration, and Maintenance) for use in all future IETF documents that refer to OAM. There are other definitions and acronyms that will be discussed while exploring the definition of the constituent parts of the OAM term.
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This Internet-Draft will expire on October 08, 2011.
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The main purpose of this document is to provide a definition of the acronym OAM (Operations, Administration, and Maintenance) for use in all future IETF documents that refer to OAM.
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 has been expanded in previous documents.
Sometimes there is a fourth letter added to the acronym:
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 a recommendation for the interpretation of the OAM acronym 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 [I-D.ietf-opsawg-oam-overview].
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 [ITU-T-I.610] 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 [IEEE.802.3-2008] and ITU-T Y.1731 [ITU-T-Y.1731].
The ITU-T M.3010 [ITU-T-M.3010] 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 effectively MEF 17 [MEF-17].
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.
The A in the OAM acronym stands for "Administration".
Examples of "administration" tools are network discovery and planning tools.
In the list above the M in the OAM acronym stands for "Maintenance" or "Management".
Maintenance and Management may have different interpretations. Maintenance is defined further in Section 3, while Management is a broader term applicable to many functions applied to the network as described in Section 3.
Since these terms have different interpretations, it is not a good idea to use them interchangeably. This document defines the "M" in the OAM acronym to mean Maintenance.
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 [ITU-T-M.20] 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 [ITU-T-M.60] 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.
In Section 4 the IETF recommended expansion of the OAM acronym is listed. This section gives some background on the definitions provided.
"Mgmt" will be used if an abbreviation for "Management" is needed. This document 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.
The OAM acronym is to be used for "Operations, Administration, and Maintenance", excluding provisioning.
OAM tools and protocols, and the "Management space" are complementary in nature. Management focuses on FCAPS (Fault, Configuration, Accounting, Performance, and Security) functionality and on manager (or 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. The management protocols tend to be "vertical", i.e., between management stations and network elements.
The components of the OAM acronym (and provisioning) are defined as follows:
"Provisioning" is outside the scope of this document, but the following definition is provided for completeness.
In general, Provisioning is used to configure the network to provide 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.
The IETF recommended expansion of the OAM acronym is given below. In addition to the OAM acronym, two other recommendations are made in this section.
OAM - Operations, Administration, and Maintenance
O&M - OAM and Management
"Mgmt" - Management
This memo includes no request to IANA.
This document provides guidance for the use of the OAM acronym in other documents. This document does not have direct security implications.
Misunderstanding of an acronym may lead to incorrect specification or implementation which may, in turn, open up security concerns with protocols or deployed networks. Clarifying the meaning of OAM is, therefore, a benefit for future stability of specifications.
The following individuals significantly contributed to this document.
Thanks to the experts of ITU-T SG 15 for their review and comments.