Gap Analysis for Layer and Technology Independent OAM Management in the Multi-Layer Environment
draft-txh-opsawg-lime-gap-analysis-00

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Authors Yuji Tochio  , Huub van Helvoort  , Liang Xia 
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IDR Working Group                                              Y. Tochio
Internet-Draft                                                   Fujitsu
Intended status: Standards Track                         H. van Helvoort
Expires: March 30, 2015                                   Hai Gaoming BV
                                                                  L. Xia
                                                                  Huawei
                                                      September 26, 2014

Gap Analysis for Layer and Technology Independent OAM Management in the
                        Multi-Layer Environment
                 draft-txh-opsawg-lime-gap-analysis-00

Abstract

   This draft analyses the existing management plane OAM related works
   in different SDOs, against the key objectives of Layer Independent
   OAM Management (LIME), to find the gap between them.  The results can
   be used as the guidance for further work.

Status of This Memo

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   This Internet-Draft will expire on March 30, 2015.

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   include Simplified BSD License text as described in Section 4.e of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Existing OAM Related Works  . . . . . . . . . . . . . . . . .   4
     3.1.  Management Information Models . . . . . . . . . . . . . .   5
     3.2.  IEEE CFM MIB  . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  MEF SOAM FM and PM MIB  . . . . . . . . . . . . . . . . .   6
     3.4.  IETF Technology-specific MIB Series . . . . . . . . . . .   7
     3.5.  MEF CFM and SOAM YANG Data Model  . . . . . . . . . . . .   7
     3.6.  YANG Model for OAM Management and Technology-specific
           extensions  . . . . . . . . . . . . . . . . . . . . . . .   7
     3.7.  Discussion  . . . . . . . . . . . . . . . . . . . . . . .   8
       3.7.1.  Consolidation in the Management Plane . . . . . . . .   8
       3.7.2.  A Generic and Reusable OAM Data Model . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Operations, Administration, and Maintenance (OAM) mechanisms are
   critical building blocks in network operations that are used for
   service assurance, fulfillment, or service diagnosis,
   troubleshooting, and repair.  The current practice is maintenance and
   troubleshooting are achieved per technology and per layer.  The
   operation process can be very cumbersome.

   Due to this fact, [LIME-PS] discusses a valuable direction in
   management plane by consolidating OAM information from each layer
   using centralized management entity and have a unified and consistent
   OAM view of multi-layer network.  Operators can rely on consolidated
   OAM management to correlate different layer OAM information (e.g.,
   fault, defects and network failure), and quickly identify the faulty
   element with its layer information in the network path.  The second
   important objective of LIME is to achieve a layer and technology
   independent OAM view of network and allow management application
   present to the user an abstract view of this network and its
   supporting layers that is strictly topological, free of any
   technology specific information.  This means an abstract and generic
   OAM management model in management plane should be developed firstly,
   and then any technology-specific OAM data model can be developed by
   extending and inheriting from it.  Generic OAM management model can

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   provide a consistent configuration, reporting, and presentation for
   the OAM mechanisms.  It also can mitigate the problem related to
   specific OAM technology dependency.  [LIME-UC] lists the key use case
   for LIME application.

   This draft analyses the existing management plane OAM related works
   in several SDOs, against the key objectives of LIME, to find the gap
   between them.  The results can be used as the guidance for further
   work.

2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [RFC2119].

2.1.  Terminology

   DM Data Model

   EMS  Element Management System [G.8052]

   IM Information Model

   NMS  Network Management System [G.8052]

   MP Maintenance Point [802.1Q]

   MEP  Maintenance Entity Group End Point [Y.1731] [RFC6371]

   MIP  Maintenance Entity Group Intermediate Point [Y.1731] [RFC6371]

   MEG  Maintenance Entity Group [Y.1731] [RFC6371]

   ME Maintenance Entity [Y.1731] [RFC6371]

   MD Maintenance Domain [802.1Q]

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   MPLS  Multiprotocol Label Switching

   NE Network Element

   NVO3  Network Virtualization Overlays

   OAM  Operations, Administration, and Maintenance [RFC6291]

   LIME  Layer Independent OAM Management [LIME-PS]

   SF Service Function Chaining

   SFF  Service Function Forwarder

   SDO  Standard Developing Organization

3.  Existing OAM Related Works

   Two objectives of LIME are:

   o  Consolidated OAM Management

   o  Layer and technology independent OAM Management

   To achieve these two objectives and accelerate Yang data model
   development, we can use Existing Information model in ITU-T and MEF,
   OAM MIB Module and CFM model as basis and directly develop Yang Data
   model.

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    +---------------+   +---------------+    +----------+
    | Existing IM   |   | OAM MIB Module|    | CFM Model|
    | in MEF, ITU-T |   |  (IETF, IEEE, |    | Y.1731   |
    | (e.g.,MEF 7.1 |   |     MEF)      |    |          |
    | ITU-T G.8052) |   +-------|-------+    +-----|----+
    +--------|------+           |                  |
             |                  |                  |
             -------------------|------------------|
                         +-----------------+
                         | Yang Data Model |
                         |for OAM Management
                         +------+----------+
                                | Augument/Inherit
                      +---------+-------------+
                      |Specific technology OAM|
                      |    Data Model         |
                      +-----------------------+

                        Yang Data Model Development

   Following are the detailed surveys for the existing management plane
   OAM works.

3.1.  Management Information Models

   ITU-T's Recommendation [G.8052] and [G.8152] provide the management
   protocol-neutral information models for managing network elements in
   the Ethernet transport network and MPLS-TP transport network as
   defined in Recommendations [G.8010] and [G.8110.1] respectively.
   They contain the object classes for the Ethernet and MPLS-TP NE
   management.  It includes the Termination Points (TP), Maintenance
   Entity Group (MEG) End Point (MEP), MEG Intermediate Point (MIP),
   Traffic Conditioning & Shaping (TCS), Loss Measurement (LM), Delay
   Measurement (DM), and the general Performance Monitoring (PM) Current
   Data (CD) and History Data (HD).  [G.8052] has been published.
   [G.8152] is still in progress.

   [MEF-7.1] specifies the EMS-NMS interface profile identifying the
   managed objects (i.e. logical UML objects) needed to support Metro
   Ethernet services.  This specification provides the profile of
   management entities based on ITU-T [Q.840.1], and also provides a
   mapping to the TMF's MTNM 3.5 Ethernet model.  Specifically this
   document adds management support for Service OAM.  The Ethernet
   Service OAM object definitions include common OAM objects (e.g.,
   EthMe, EthMeg, EthMep, EthMip, EthMp, EthMd, EthMepPeerInfo), Fault
   Management Objects (e.g., Continuity Check, Loopback, Link Trace,
   Signal Functions), Performance Monitoring Objects (e.g., Abstract

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   Performance Monitoring Objects, Loss Measurement, Delay Measurement,
   Function Sets).

   The above OAM information models provide the baseline for the further
   definitions of OAM MIB modules and OAM YANG model.  But they are
   still technology-specific definitions, not abstract and generic
   enough.

3.2.  IEEE CFM MIB

   The IEEE8021-CFM-MIB MIB Module and IEEE8021-CFM-V2-MIB MIB module
   are CFM MIB modules for managing IEEE CFM in [802.1Q].  The former
   document defines all the MIB objects that used to read, create,
   modify, and delete OAM related information (i.e., CFM Stack Table, MD
   Table, MA Table, MEP Table, LinkTrace Reply Table, MEP DB Table,
   Notifications Table, etc).  The latter document defines CFM V2 module
   for managing IEEE CFM.  It contains objects that replace those
   deprecated in the IEEE8021-CFM-MIB module (i.e., CFM Stack Table, CFM
   Vlan Table, CFM Default MD Level Table, etc).

   These CFM MIB modules defined for Ethernet network are the input for
   analyzing what the generic OAM data model should be and have.

3.3.  MEF SOAM FM and PM MIB

   [MEF-31] defines the MIB modules for MEF Service OAM Fault Management
   (FM).  This document includes two MIBs necessary to support the MEF
   SOAM FM functionality: the MEF-SOAM-TC-MIB that includes the Textual
   Conventions (TC) for the SOAM MIB family and the MEF-SOAM-FM-MIB that
   includes extensions to Connectivity Fault Management (CFM) as
   developed in IEEE [802.1Q], including MIBs found in [IEEE 802.1Q] and
   [IEEE 802.1ap], and enhanced by ITU-T [Y.1731] to support the SOAM FM
   functions as presented in the [MEF-30] specification.  It includes
   the SOAM FM MIB objects such as mefSoamNet, mefSoamMeg, mefSoamMep,
   mefSoamCc, mefSoamAis, mefSoamLb, etc.

   [MEF-36] specifies the Performance Monitoring (PM) MIB necessary to
   manage SOAM implementations that satisfy the Service OAM requirements
   and framework specified by [MEF-17], the Service OAM Performance
   Monitoring requirements as specified by [MEF-35], and the Service OAM
   management objects as specified by [MEF-7.1] which are applicable to
   Performance Monitoring functions.  Two non-MEF documents serve as the
   baseline documents for this work: ITU-T [Y.1731] and IEEE [802.1Q].
   The SOAM PM MIB is divided into a number of different object
   groupings: the PM MIB MEP Objects, PM MIB Loss Measurement Objects,
   PM MIB Delay Measurement Objects, and SOAM PM Notifications.

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   These documents' MIB definitions are also in the Ethernet layer and
   are the input for the LIME works.

3.4.  IETF Technology-specific MIB Series

   IETF specifies a series MIB module for various technologies, which
   includes: [RFC7331] for BFD MIB, [RFC4560] for PING MIB, [MPLS-TP OAM
   ID MIB] for MPLS-TP MIB, etc.

   All these documents are technology-specific and limited to layer
   1/2/3.  The OAM MIB definition above layer 3 (i.e., SFC service
   layer) is still missing in IETF.  Further study is needed to abstract
   a unified and general OAM data model for any network layers from them
   and other SDOs' OAM works.

3.5.  MEF CFM and SOAM YANG Data Model

   SOAM CFM YANG module [MEF-38] is an important work that defines the
   managed objects necessary to support SOAM CFM functionality by using
   the IETF YANG Module Language [RFC6020].  This YANG module contains
   the management data definitions for the management of Ethernet
   Services OAM for Connectivity Fault Management.

   [MEF-39] provides the YANG module that supports the Ethernet Service
   OAM (SOAM) Performance Monitoring functions.  This YANG module
   contains the management data definitions for the management of
   Ethernet Services OAM for Performance Monitoring and extends the
   Connectivity Fault Management (CFM) YANG modules.

   These MEF OAM YANG works are important reference for the LIME works.

3.6.  YANG Model for OAM Management and Technology-specific extensions

   [I-D.tissa-netmod-oam] is an IETF work that creates a YANG unified
   data model for OAM that is based on IEEE CFM model.  This model may
   be used also for IP OAM functionality.  This effort is focused on the
   management plane of OAM and should be complemented by an accompanying
   data-plane and/or control-plane work.  It may require also some
   extensions to support wider variety of functions and technologies.

   [I-D.tissa-nvo3-yang-oam] extends the Generic YANG model defined in
   [I-D.tissa-netmod-oam] for OAM with NVO3 technology specifics and
   presents Yang Module for NVO3 OAM.

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3.7.  Discussion

   Until now, all the OAM data models and operations in the management
   plane are technology dependent and limited to one specific layer.

3.7.1.  Consolidation in the Management Plane

   Consolidation means here the management functions are capable of
   receiving and reacting to related information from every transport
   segment at every layer in the network.  The reacting to related
   information from every layer can include:

   o  Synthesize the OAM information from every layer;

   o  Exchange and correlation between the OAM information from every
      layer;

   o  Orchestrating and coordinating the OAM operations among every
      layer based on the above information for an end to end service.

   However, there is little consolidation of OAM in management plane nor
   well-documented inter-layer OAM operations within current MIB
   definition works by IEEE, MEF or IETF, and YANG model definition work
   by MEF.  This also results in an end to end and service-level OAM
   view of network is hardly generated in the management plane.

   In addition to consolidation, a layer and technology independent OAM
   view of network is also important for multi-layer OAM.  The challenge
   to get this view is to abstract in a way that retains in the
   management plane as much useful information as possible while
   filtering the data that is not needed to be leaked to layers in the
   data plane.  An important part of this effort is a clear
   understanding of what information is actually needed.  Current
   existing OAM works in various SDOs do not consider this issue now.

3.7.2.  A Generic and Reusable OAM Data Model

   Another aspect is about the OAM data model specification.  The
   existing traditional implementations of data models in management
   plane, such as MIB, YANG, are all technology-specific.  They specify
   the MIB module or YANG model for specific technology respectively.
   There are many overlapping contents and repeated works during specify
   data model for any technologies.  The same condition happens each
   time when a new technology needs to specify its own data model in
   management plane.

   So, a generic and reusable OAM data model is essential and valuable
   for this kind of work.  And to the extent that management operations

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   are being redesigned in terms of YANG modules [RFC6020] over NETCONF
   [RFC6241], the opportunity appears to use the concept of layer and
   technology independent abstraction to extract the reusable parts,
   simplifying the work on the remainder.

4.  Security Considerations

   TBD.

5.  Normative References

   [G.8052]   "Protocol-neutral management information model for the
              Ethernet transport capable network element", Draft
              Recommendation ITU-T G.8052/Y.1346, August 2013.

   [G.8110.1]
              "Architecture of MPLS Transport Profile (MPLS-TP) layer
              network", ITU-T G.8110.1/Y.1370.1, December 2011.

   [G.8152]   "Protocol-neutral management information model for the
              MPLS-TP network element", Draft Recommendation ITU-T
              G.8152/Y.1375, September 2015.

   [I-D.tissa-netmod-oam]
              Senevirathne, T., Finn, N., Kumar, D., Salam, S., and C.
              Pignataro, "YANG Data Model for Generic Operations,
              Administration, and Maintenance (OAM)", draft-tissa-
              netmod-oam-01 (work in progress), June 2014.

   [I-D.tissa-nvo3-yang-oam]
              Senevirathne, T., "YANG Data Model for NVO3 Operations,
              Administration, and Maintenance(OAM)", ID draft-tissa-
              nvo3-yang-oam-00, June 2014.

   [IEEE802.1Q]
              "Media Access Control (MAC) Bridges and Virtual Bridged
              Local Area Networks", IEEE Std 802.1Q-2011, August 2011.

   [LIME-PS]  Taylor, T., "Problem Statement for Layer and Technology
              Independent OAM in a Multi-Layer Environment", ID draft-
              edprop-opsawg-multi-layer-oam-ps, September 2014.

   [LIME-UC]  King, D., "Use Cases and Requirements for Layer
              Independent OAM Management in multi-layer environments",
              ID draft-king-opsawg-lime-multi-layer-oam-use-case,
              September 2014.

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   [MEF-30]   "Service OAM Fault Management Implementation Agreement",
              MEF 30, January 2011.

   [MEF-31]   "Service OAM Fault Management Definition of Managed
              Objects", MEF 31, January 2011.

   [MEF-35]   "Service OAM Performance Monitoring Implementation
              Agreement", MEF 35, January 2012.

   [MEF-36]   "Service OAM SNMP MIB for Performance Monitoring", MEF 36,
              January 2012.

   [MEF-38]   "Service OAM Fault Management YANG Modules", MEF 38, April
              2012.

   [MEF-39]   "Service OAM Performance Monitoring YANG Module", MEF 39,
              April 2012.

   [MEF-7.1]  "EMS-NMS Information Model -Phase 2", Metro Ethernet Forum
              MEF 7.1, 2009.

   [Q.840.1]  "Requirements and Analysis for NMS-EMS Management
              Interface of Ethernet over Transport and Metro Ethernet
              Network", Draft Recommendation ITU-T Q.840.1, 2007.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", March 1997.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC6291]  Andersson, L., "Guidelines for the use of the "OAM"
              Acronym in the IETF", RFC 6291, June 2011.

   [RFC6371]  Busi, I. and D. Allan, "Operations, Administration, and
              Maintenance Framework for MPLS-Based Transport Networks",
              RFC 6371, September 2011.

   [RFC7331]  Nadeau, T., Ali, Z., and N. Akiya, "Bidirectional
              Forwarding Detection (BFD) Management Information Base",
              RFC 7331, August 2014.

   [Y.1731]   "OAM functions and mechanisms for Ethernet based
              networks", ITU-T Recommendation G.8013/Y.1731, 2013.

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Authors' Addresses

   Yuji Tochio
   Fujitsu

   Email: tochio@jp.fujitsu.com

   Huub van Helvoort
   Hai Gaoming BV

   Email: huubatwork@gmail.com

   Liang (Frank) Xia
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: Frank.xialiang@huawei.com

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