Network Working Group D. King (Editor) Internet-Draft Old Dog Consulting Intended status: Informational M. Venkatesan (Editor) Expires: November 12, 2011 Aricent June 12, 2011 Multiprotocol Label Switching Transport Profile (MPLS-TP) MIB-based Management Overview draft-ietf-mpls-tp-mib-management-overview-04.txt Abstract A range of Management Information Base (MIB) modules has been developed to help model and manage the various aspects of Multiprotocol Label Switching (MPLS) networks. These MIB modules are defined in separate documents that focus on the specific areas of responsibility of the modules that they describe. The MPLS Transport Profile (MPLS-TP) is a profile of MPLS functionality specific to the construction of packet-switched transport networks. This document describes the MIB-based architecture for MPLS-TP, and indicates the interrelationships between different existing MIB modules that can be leveraged for MPLS-TP network management and identifies areas where additional MIB modules would be required. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 12, 2011. King & Venkatesan, et al. [Page 1] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 Copyright Notice Copyright (c) 2011 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 (http://trustee.ietf.org/license-info) 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.................................................3 1.1 MPLS-TP Management Function.................................4 2. Terminology..................................................4 3. The SNMP Management Framework................................4 4. Overview of Existing Work....................................5 4.1. MPLS Management Overview and Requirements...............5 4.2. An Introduction to the MPLS and Pseudowire MIB Modules..5 4.2.1. Structure of the MPLS MIB OID Tree...............5 4.2.2. Textual Convention Modules.......................6 4.2.3. Label Edge Router (LER) Modules..................7 4.2.4. Label Switching Router Modules...................7 4.2.5. Label Switched Path Modules......................7 4.2.6. Pseudowire Modules...............................8 4.2.7. Routing and Traffic Engineering..................9 4.2.8. Resiliency.......................................9 4.2.9. Fault Management and Performance Management......10 4.2.10. MIB Module Interdependencies....................11 4.2.11. Dependencies on External MIB Modules............13 5. Applicability of MPLS MIB modules to MPLS-TP.................14 5.1 MPLS-TP Tunnel...........................................14 5.1.1 Gap Analysis.......................................14 5.1.2 Recommendations....................................15 5.2 MPLS-TP Pseudowire.......................................15 5.2.1 Gap Analysis.......................................15 5.2.2 Recommendations....................................15 5.3 MPLS-TP Sections.........................................15 5.3.1 Gap Analysis.......................................15 5.3.2 Recommendations....................................15 5.4 MPLS-TP OAM..............................................16 5.4.1 Gap Analysis.......................................16 5.4.2 Recommendations....................................16 King & Venkatesan, et al. [Page 2] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 5.5 MPLS-TP Protection Switching and Recovery................16 5.5.1 Gap Analysis.......................................16 5.5.2 Recommendations....................................16 5.6 MPLS-TP Interfaces.......................................16 5.6.1 Gap Analysis.......................................16 5.6.2 Recommendations....................................17 6. An Introduction to the MPLS-TP MIB Modules...................17 6.1 MPLS-TP MIB Modules......................................17 6.1.1 Structure of the MPLS-TP MIB OID Tree.............17 6.1.2 Textual Conventions for MPLS-TP...................18 6.1.3 Identifiers for MPLS-TP...........................18 6.1.4 LSR MIB Extensions for MPLS-TP....................18 6.1.5 Tunnel Extensions for MPLS-TP.....................18 6.2 PWE3 MIB Modules for MPLS-TP.............................18 6.2.1 Structure of the PWE3 MIB OID Tree for MPLS-TP....19 6.2.2 Pseudowire Textual Conventions for MPLS-TP........19 6.2.3 Pseudowire Extensions for MPLS-TP.................19 6.2.4 Pseudowire MPLS Extensions for MPLS-TP............19 6.3 OAM MIB Modules for MPLS-TP..............................19 6.3.1 Structure of the OAM MIB OID Tree for MPLS-TP.....19 6.3.2 LSP Ping MIB module...............................20 6.3.3 BFD MIB module....................................20 6.3.4 Common OAM MIB modules............................20 6.4. Protection Switching and Recovery MIB Modules for MPLS-TP.............................................20 6.4.1 Structure of the Protection Switching and Recovery MIB OID Tree for MPLS-TP.............21 6.4.2 Linear Protection Switching MIB module............21 6.4.3 Ring Protection Switching MIB module..............21 6.4.4 Mesh Protection Switching MIB module..............21 7. Management Options...........................................21 8. Security Considerations......................................21 9. IANA Considerations..........................................22 10. Acknowledgements............................................22 11. References..................................................22 11.1. Normative References...................................22 11.2. Informational References...............................24 12. Authors' Addresses..........................................26 1. Introduction The MPLS Transport Profile (MPLS-TP) is a packet transport technology based on a profile of the MPLS functionality specific to the construction of packet-switched transport networks. MPLS is described in [RFC3031] and requirements for MPLS-TP are specified in [RFC5654]. King & Venkatesan, et al. [Page 3] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 A range of Management Information Base (MIB) modules has been developed to help model and manage the various aspects of Multiprotocol Label Switching (MPLS) networks. These MIB modules are defined in separate documents that focus on the specific areas of responsibility of the modules that they describe. An MPLS-TP network can be operated via static provisioning of transport paths, or the elective use of a Generalized MPLS (GMPLS) control plane to support dynamic provisioning of transport paths. This document describes the MIB-based management architecture for MPLS-TP and indicates the interrelationships between different existing MIB modules that should be leveraged for MPLS-TP network management, if SNMP is used for the management interface and identifies areas where additional MIB modules would be required. Note that [RFC5951] does not specify a preferred management interface protocol to be used as the standard protocol for managing MPLS-TP networks. 1.1 MPLS-TP Management Function The management of the MPLS-TP networks is inseparable from that of its client networks so that the same means of management can be used regardless of the client. The management functions of MPLS-TP includes fault management, configuration management, performance monitoring, and security management. The purpose of the management function is to provide control and monitoring over the protocol mechanisms and procedures that constitute the building blocks for a transport profile of MPLS. The requirements for the network management functionality are found in [RFC5951]. A description of the network and element management architectures that can be applied to the management of MPLS-based transport networks is found in [RFC5950]. 2. Terminology This document also uses terminology from the MPLS architecture document [RFC3031] and the following MPLS related MIB modules: MPLS TC MIB [RFC3811], MPLS LSR MIB [RFC3813], MPLS TE MIB [RFC3812], MPLS LDP MIB [RFC3815], MPLS FTN MIB [RFC3814] and TE LINK MIB [RFC4220]. 3. The SNMP Management Framework Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). King & Venkatesan, et al. [Page 4] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 [RFC3410]. This document discusses MIB modules that are compliant to the SMIv2, which is described in [RFC2578], [RFC2579] and [RFC2580]. 4. Overview of Existing Work This section describes the existing tools and techniques for managing and modeling MPLS networks, devices, and protocols. It is intended to provide a description of the tool kit that is already available. Section 5 of this document outlines the applicability of existing MPLS MIB modules to MPLS-TP, describes the optional use of GMPLS MIB modules in MPLS-TP networks, and examines the additional MIB modules and objects that would be required for managing an MPLS-TP network. 4.1. MPLS Management Overview and Requirements [RFC4378] outlines how data plane protocols can assist in providing the Operations and Management (OAM) requirements outlined in [RFC4377] and how it is applied to the management functions of fault, configuration, accounting, performance, and security (commonly known as FCAPS) for MPLS networks. [RFC4221] describes the management architecture for MPLS. In particular, it describes how the managed objects defined in various MPLS-related MIB modules model different aspects of MPLS, as well as the interactions and dependencies between each of these MIB modules. [RFC4377] describes the requirements for user and data plane OAM and applications for MPLS. [RFC5654] describes the requirements for the optional use of a control plane to support dynamic provisioning of MPLS-TP transport paths. The MPLS-TP LSP control plane is based on GMPLS and is described in [RFC3945]. 4.2. An Introduction to the MPLS and Pseudowire MIB Modules 4.2.1. Structure of the MPLS MIB OID Tree The MPLS MIB OID tree has the following structure. It is based on the tree originally set out in section 4.1 of [RFC4221] and has been enhanced to include other relevant MIB modules. King & Venkatesan, et al. [Page 5] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 mib-2 -- RFC 2578 [RFC2578] | +-transmission | | | +- mplsStdMIB | | | | | +- mplsTCStdMIB -- MPLS-TC-STD-MIB [RFC3811] | | | | | +- mplsLsrStdMIB -- MPLS-LSR-STD-MIB [RFC3813] | | | | | +- mplsTeStdMIB -- MPLS-TE-STD-MIB [RFC3812] | | | | | +- mplsLdpStdMIB -- MPLS-LDP-STD-MIB [RFC3815] | | | | | +- mplsLdpGenericStdMIB | | | -- MPLS-LDP-GENERIC-STD-MIB [RFC3815] | | | | | +- mplsFTNStdMIB -- MPLS-FTN-STD-MIB [RFC3814] | | | | | +- gmplsTCStdMIB -- GMPLS-TC-STD-MIB [RFC4801] | | | | | +- gmplsTeStdMIB -- GMPLS-TE-STD-MIB [RFC4802] | | | | | +- gmplsLsrStdMIB -- GMPLS-LSR-STD-MIB [RFC4803] | | | | | +- gmplsLabelStdMIB -- GMPLS-LABEL-STD-MIB [RFC4803] | | | +- teLinkStdMIB -- TE-LINK-STD-MIB [RFC4220] | | | +- pwStdMIB -- PW-STD-MIB [RFC5601] | +- ianaGmpls -- IANA-GMPLS-TC-MIB [RFC4802] | +- ianaPwe3MIB -- IANA-PWE3-MIB [RFC5601] | +- pwEnetStdMIB -- PW-ENET-STD-MIB [RFC5603] | +- pwMplsStdMIB -- PW-MPLS-STD-MIB [RFC5602] | +- pwTDMMIB -- PW-TDM-MIB [RFC5604] | +- pwTcStdMIB -- PW-TC-STD-MIB [RFC5542] Note: The OIDs for MIB modules are assigned and managed by IANA. They can be found in the referenced MIB documents. 4.2.2. Textual Convention Modules King & Venkatesan, et al. [Page 6] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 MPLS-TC-STD-MIB [RFC3811], GMPLS-TC-STD-MIB [RFC4801], IANA-GMPLS-TC-MIB [RFC4802] and PW-TC-STD-MIB [RFC5542] contains the Textual Conventions for MPLS and GMPLS networks. These Textual Conventions should be imported by MIB modules which manage MPLS and GMPLS networks. Section 3.2.11. highlights dependencies on additional external MIB modules 4.2.3. Label Edge Router (LER) Modules Label Edge Router (LER) Module helps in mapping data to LSP's based on the network layer header. The ingress device of the MPLS network is called Label Edge Routers (LER). At the LER when an unlabelled packet enters the ingress interface, network layer header is parsed to classify the packet to a forwarding equivalence class (FEC). Each FEC is mapped to an LFIB entry to encapsulate the unlabelled packet with one or more label entries referred to as the label stack. Each label stack entry consists of a label, the 3 TC-bits for classifying the Traffic Class, the bottom of stack bit, and TTL. MPLS-FTN-STD-MIB [RFC3814] describes the managed objects for mapping FEC's to label bindings. 4.2.4. Label Switching Router Modules A router which performs MPLS forwarding is known as an LSR. An LSR receives a labelled packet and performs forwarding action based on the label received. LSR maintains a mapping of an incoming label and incoming interface to one or more outgoing label and outgoing interfaces in its forwarding database. When a labelled packet is received, LSR examines the topmost label in the label stack and then does 'swap', 'push' or 'pop' operation based on the contents. MPLS-LSR-STD-MIB [RFC3813] describes the managed objects for modeling a Multiprotocol Label Switching (MPLS) [RFC3031] LSR. MPLS-LSR-STD-MIB [RFC3813] contains the managed objects to maintain mapping of in-segments to out-segments. 4.2.5. Label Switched Path Modules The path taken through the MPLS domain by a packet is referred to as a label switched path (LSP). It is possible that this path may not be understood or completely stored in any one LSR within the MPLS domain. MPLS-LSR-STD-MIB [RFC3813] describes the required objects to define the LSP. King & Venkatesan, et al. [Page 7] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 4.2.6. Pseudowire Modules The PW (Pseudowire) MIB architecture provides a layered modular model into which any supported emulated service such as Frame Relay, ATM, Ethernet, TDM and SONET/SDH can be connected to any supported packet switched network (PSN) type. This MIB architecture is modeled based on PW3 architecture [RFC3985]. Emulated Service Layer, Generic PW Layer and PSN VC Layer constitute the different layers of the model. A combination of the MIB modules belonging to each layer provides the glue for mapping the emulated service onto the native PSN service. At least three MIB modules each belonging to a different layer are required to define a PW emulated service. o Service-Specific module is dependent on the emulated signal type and helps in modeling emulated service layer. PW-ENET-STD-MIB [RFC5603] describes a model for managing Ethernet pseudowire services for transmission over a PSN. This MIB module is generic and common to all types of PSNs supported in the Pseudowire Emulation Edge-to-Edge (PWE3) architecture [RFC3985], which describes the transport and encapsulation of L1 and L2 services over supported PSN types. In particular, the MIB module associates a port or specific VLANs on top of a physical Ethernet port or a virtual Ethernet interface (for Virtual Private LAN Service (VPLS)) to a point-to-point PW. It is complementary to the PW-STD-MIB [RFC5601], which manages the generic PW parameters common to all services, including all supported PSN types. PW-TDM-MIB [RFC5604] describes a model for managing TDM pseudowires, i.e., TDM data encapsulated for transmission over a Packet Switched Network (PSN). The term TDM in this document is limited to the scope of Plesiochronous Digital Hierarchy (PDH). It is currently specified to carry any TDM Signals in either Structure Agnostic Transport mode (E1, T1, E3, and T3) or in Structure Aware Transport mode (E1, T1, and NxDS0) as defined in the Pseudowire Emulation Edge-to-Edge (PWE3) TDM Requirements document [RFC4197]. o Generic PW Module configures general parameters of the PW that are common to all types of emulated services and PSN types. PW-STD-MIB [RFC5601] defines a MIB module that can be used to manage pseudowire (PW) services for transmission over a Packet Switched Network (PSN) [RFC3931] [RFC4447]. This MIB module provides generic management of PWs that is common to all types of PSN and PW services defined by the IETF PWE3 Working Group. King & Venkatesan, et al. [Page 8] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 o PSN-specific module associate the PW with one or more "tunnels" that carry the service over the PSN. There is a different module for each type of PSN. PW-MPLS-STD-MIB [RFC5602] describes a model for managing pseudowire services for transmission over different flavors of MPLS tunnels. The general PW MIB module [RFC5601] defines the parameters global to the PW regardless of the underlying Packet Switched Network (PSN) and emulated service. This document is applicable for PWs that use MPLS PSN type in the PW-STD-MIB. Additionally this document describes the MIB objects that define pseudowire association to the MPLS PSN, that is not specific to the carried service. Together, [RFC3811], [RFC3812] and [RFC3813] describe the modeling of an MPLS tunnel, and a tunnel's underlying cross-connects. This MIB module supports MPLS-TE PSN, non-TE MPLS PSN (an outer tunnel created by the Label Distribution Protocol (LDP) or manually), and MPLS PW label only (no outer tunnel). 4.2.7. Routing and Traffic Engineering In MPLS traffic engineering, it's possible to specify explicit routes or choose routes based on QOS metrics in setting up a path such that some specific data can be routed around network hot spots. TE LSPs can be setup through a management plane or a control plane. MPLS-TE-STD-MIB [RFC3812] describes managed objects for modeling a Multiprotocol Label Switching (MPLS) [RFC3031] based traffic engineering. This MIB module should be used in conjunction with the companion document [RFC3813] for MPLS based traffic engineering configuration and management. 4.2.8. Resiliency An MPLS resiliency is to make sure that there is no interruption to traffic when the failure occurs within the system or network. Various components of MPLS resiliency solutions are, 1) Graceful restart in LDP and RSVP-TE modules 2) Make Before Break 3) Protection Switching for LSPs 4) Fast ReRoute for LSPs 5) PW redundancy The below modules only support the SNMP based mib management for MPLS resiliency. MPLS Fast Reroute is a restoration network resiliency mechanism used in MPLS TE to redirect the traffic onto the backup LSP's in 10s of milliseconds in case of link or node failure across the LSP. King & Venkatesan, et al. [Page 9] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 MPLS-FRR-GENERAL-STD-MIB [draft-ietf-mpls-fastreroute-mib-14] contains objects that apply to any MPLS LSR implementing MPLS TE fast reroute functionality. MPLS-FRR-ONE2ONE-STD-MIB [draft-ietf-mpls-fastreroute-mib-14] contains objects that apply to one-to-one backup method. MPLS-FRR-FACILITY-STD-MIB [draft-ietf-mpls-fastreroute-mib-14] contains objects that apply to facility backup method. Protection Switching mechanisms have been designed to provide network resiliency for MPLS network. Different types of protection switching mechanisms such as 1:1, 1:N, 1+1 have been designed. 4.2.9. Fault Management and Performance Management MPLS manages the LSP and pseudowire faults through the use of LSP ping [RFC4379], VCCV [RFC5085], BFD for LSPs [RFC5884] and BFD for VCCV [RFC5885] tools. Current MPLS focuses on the in and/or out packet counters, errored packets, discontinuity time. Some of the MPLS and Pseudowire performance tables used for performance management are given below. mplsTunnelPerfTable provides several counters (packets forwarded, packets dropped because of errors) to measure the performance of the MPLS tunnels. mplsInterfacePerfTable provides performance information (incoming and outgoing labels in use and lookup failures) on a per-interface basis. mplsInSegmentPerfTable contains statistical information (total packets received by the insegment, total errored packets received, total packets discarded, discontinuity time) for incoming MPLS segments to an LSR. mplsOutSegmentPerfTable contains statistical information (total packets received, total errored packets received, total packets discarded, discontinuity time) for outgoing MPLS segments from an LSR. mplsFTNPerfTable contains performance information for the specified interface and an FTN entry mapped to this interface. mplsLdpEntityStatsTable and mplsLdpSessionStatsTable contain statistical information (session attempts, errored packets, notifications) about an LDP entity. King & Venkatesan, et al. [Page 10] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 pwPerfCurrentTable, pwPerfIntervalTable, pwPerf1DayIntervalTable provides pseudowire performance information (in and/or out packets) based on time (current interval, preconfigured specific interval, 1day interval). pwEnetStatsTable contains statistical counters specific for Ethernet PW. pwTDMPerfCurrentTable, pwTDMPerfIntervalTable and pwTDMPerf1DayIntervalTable contain statistical informations accumulated per 15-minute, 24 hour, 1 day respectively. gmplsTunnelErrorTable and gmplsTunnelReversePerfTable provides information about performance errored packets and in/out packet counters. 4.2.10. MIB Module Interdependencies This section provides an overview of the relationship between the MPLS MIB modules for managing MPLS networks. More details of these relationships are given below. [RFC4221] mainly focuses on the MPLS MIB module interdependencies, this section also highlights the GMPLS and PW MIB modules interdependencies. The relationship "A --> B" means A depends on B and that MIB module A uses an object, object identifier, or textual convention defined in MIB module B, or that MIB module A contains a pointer (index or RowPointer) to an object in MIB module B. King & Venkatesan, et al. [Page 11] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 +-------> MPLS-TC-STD-MIB <-----------------------------------------+ | ^ | | | | | MPLS-LSR-STD-MIB <--------------------------------+ | | | | +<----------------------- MPLS-LDP-STD-MIB ---------------->+ | | ^ | | | | | | +<-- MPLS-LDP-GENERIC-STD-MIB ------>+ | | | | | +<------ MPLS-FTN-STD-MIB ---------+----------------------->+ | | | | | | V | | +<------------- MPLS-TE-STD-MIB ->+ | | GMPLS-TC-STD-MIB ------------>+ | ^ | | | | +---+ +<-- GMPLS-LABEL-STD-MIB -->+ | ^ ^ ^ | | | | | | +----> PW-TC-STD-MIB | GMPLS-LSR-STD-MIB --------------->+ | | ^ ^ | | | | | | | IANA-PWE3-MIB | | | IANA-GMPLS-TC-MIB | | ^ | | | ^ | | | | | | | | | | +<--- GMPLS-TE-STD-MIB ------------->+ | | ^ | +<--- PW-STD-MIB <------+ | | | | | | +<--- PW-ENET-STD-MIB ->+ | | | ^ | | | | | | +<---------------- PW-MPLS-STD-MIB -------------------------------->+ Thus: - All the MPLS MIB modules depend on MPLS-TC-STD-MIB. - All the GMPLS MIB modules depend on GMPLS-TC-STD-MIB. - All the PW MIB modules depend on PW-TC-STD-MIB. - MPLS-LDP-STD-MIB, MPLS-TE-STD-MIB, MPLS-FTN-STD-MIB, GMPLS-LSR-STD-MIB, and PW-MPLS-STD-MIB contain references to objects in MPLS-LSR-STD-MIB. - MPLS-LDP-GENERIC-STD-MIB contains references to objects in MPLS-LDP-STD-MIB. King & Venkatesan, et al. [Page 12] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 - MPLS-FTN-STD-MIB, PW-MPLS-STD-MIB, and GMPLS-TE-STD-MIB contain references to objects in MPLS-TE-STD-MIB. - PW-MPLS-STD-MIB, and PW-ENET-STD-MIB contains references to objects in PW-STD-MIB. - PW-STD-MIB contains references to objects in IANA-PWE3-MIB. - GMPLS-TE-STD-MIB contains references to objects in IANA-GMPLS-TC-MIB. - GMPLS-LSR-STD-MIB contains references to objects in GMPLS-LABEL-STD-MIB. Note that there is a textual convention (MplsIndexType) defined in MPLS-LSR-STD-MIB that is imported by MPLS-LDP-STD-MIB. 4.2.11. Dependencies on External MIB Modules With the exception of MPLS-TC-STD-MIB, all the MPLS MIB modules have dependencies on the Interfaces MIB [RFC2863]. MPLS-FTN-STD-MIB references IP-capable interfaces on which received traffic is to be classified using indexes in the Interface Table (ifTable) of IF-MIB [RFC2863]. The other MPLS MIB modules reference MPLS-capable interfaces in ifTable. The Interfaces Group of IF-MIB [RFC2863] defines generic managed objects for managing interfaces. The MPLS MIB modules contain media-specific extensions to the Interfaces Group for managing MPLS interfaces. The MPLS MIB modules assume the interpretation of the Interfaces Group to be in accordance with [RFC2863], which states that ifTable contains information on the managed resource's interfaces and that each sub-layer below the internetwork layer of a network interface is considered an interface. Thus, the MPLS interface is represented as an entry in ifTable. The interrelation of entries in ifTable is defined by the Interfaces Stack Group defined in [RFC2863]. The MPLS MIB modules have dependencies with the TE-LINK-STD-MIB for maintaining the traffic engineering information. The MPLS MIB modules depend on the constrained shortest path first (CSPF) module to obtain the path required for an MPLS tunnel to reach the end point of the tunnel and BFD module to verify the data-plane failures of LSPs and PWs. King & Venkatesan, et al. [Page 13] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 Finally, all of the MIB modules import standard textual conventions such as integers, strings, timestamps, etc., from the MIB modules in which they are defined. 5. Applicability of MPLS MIB modules to MPLS-TP This section and its sub sections focus on the possible gaps that exist in the MPLS MIB modules to extend its use to MPLS-TP networks. [RFC5951] specifies the requirements for the management of equipment used in networks supporting an MPLS-TP. It also details the essential network management capabilities for operating networks consisting of MPLS-TP equipment. [RFC5950] provides the network management framework for MPLS-TP. The document explains how network elements and networks that support MPLS-TP can be managed using solutions that satisfy the requirements defined in [RFC5951]. The relationship between MPLS-TP management and OAM is described in the MPLS-TP framework [RFC5950] document. The MPLS mib modules MPLS-TE-STD-MIB [RFC3812], PW-STD-MIB [RFC5601] and MPLS-LSR-STD-MIB [RFC3813] and their associated mib modules are reused for MPLS based transport network management. Fault management and performance management form key parts of Operations, Administration, and Maintenance (OAM) function. MPLS-TP OAM is described in [MPLS-TP-OAM-FWK]. A seperate draft will provide an MPLS-TP abstract model and use a formal language to define the terminology, the information that must be retrieved and method for storing. 5.1 MPLS-TP Tunnel 5.1.1 Gap Analysis MPLS-TP tunnel can be operated over IP and/or ICC environments, below points capture the gaps in existing MPLS mib modules for managing the MPLS-TP networks. o IP based environment i. MPLS-TE-STD-MIB [RFC3812] does not support tunnel LSR identifier based on Global_ID and Node_ID. ii. MPLS-TE-STD-MIB [RFC3812] does not support corouted/associated bidirectional tunnel configurations. King & Venkatesan, et al. [Page 14] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 o ICC based environment i. MPLS-TE-STD-MIB [RFC3812] does not support tunnel LSR identifier based on ICC. ii. MPLS tunnel does not support forwarding other than the nexthop IP address. 5.1.2 Recommendations o New MIB definitions can be created for Global_Node_ID and/or ICC configurations. o MPLS-LSR-STD-MIB [RFC3813] mib module can be enhanced to identify the nexthop based on MAC address for IP-less environment. o MPLS-TE-STD-MIB [RFC3812] and MPLS-LSR-STD-MIB should be enhanced to provide static and signalling mib module extensions for corouted/associated bidirectional LSPs. 5.2 MPLS-TP Pseudowire 5.2.1 Gap Analysis MPLS-TP Pseudowire can be operated over IP and/or ICC environments, below points capture the gaps in existing PW mib modules for managing the MPLS-TP networks. o IP based environment i. PW-STD-MIB [RFC5601] does not support PW end point identifier based on Global_ID and Node_ID. ii. PW-MPLS-STD-MIB [RFC5602] does not support its opeation over corouted/associated bidirectional tunnels. o ICC based environment i. PW-STD-MIB [RFC5601] does not support PW end point identifier based on ICC. ii. Pseudowire does not support forwarding other than the nexthop IP address. 5.2.2 Recommendations o PW-MPLS-STD-MIB [RFC5602] can be enhanced to operate over corouted/associated bi-directional tunnel. o Pseudowire 129 FEC type-2 can be used in non-IP and IP environments with the required changes. 5.3 MPLS-TP Sections 5.3.1 Gap Analysis The existing MPLS MIB modules does not support MPLS-TP sections. 5.3.2 Recommendations King & Venkatesan, et al. [Page 15] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 Link specific and/or path/segment specific sections can be achieved by enhancing the IF-MIB [RFC2863], MPLS-TE-STD-MIB [RFC3812] and PW-STD-MIB [RFC5601] mib modules. 5.4 MPLS-TP OAM 5.4.1 Gap Analysis MPLS manages the LSP and pseudowire faults through LSP ping [RFC4379], VCCV [RFC5085], BFD for LSPs [RFC5884] and BFD for VCCV [RFC5885] tools. The MPLS mib modules do not support the below MPLS-TP OAM functions, o Continuity Check and Connectivity Verification o Remote Defect Indication o Route Tracing o Alarm Reporting o Lock Reporting o Lock Instruct o Client Failure Indication o Packet Loss Measurement o Packet Delay Measurement 5.4.2 Recommendations New mib modules for BFD and LSP Ping can be created to address all the gaps mentioned in the 5.4.1 Gap Analysis section. 5.5 MPLS-TP Protection Switching and Recovery 5.5.1 Gap Analysis An important aspect that MPLS-TP technology provides is protection switching. In general, the mechanism of protection switching can be described as the substitution of a protection or standby facility for a working or primary facility. The MPLS mib modules do not provide support for protection switching and recovery of three different topologies (linear, ring and mesh) available. 5.5.2 Recommendations New mib modules can be created to address all the gaps mentioned in the 5.5.1 Gap Analysis section. 5.6 MPLS-TP Interfaces 5.6.1 Gap Analysis King & Venkatesan, et al. [Page 16] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 As per [MPLS-TP-IDENTIFIERS], an LSR requires identification of the node itself and of its interfaces. An interface is the attachment point to a server layer MPLS-TP section or MPLS-TP tunnel. The MPLS mib modules do not provide support for configuring the interfaces within the context of an operator. 5.6.2 Recommendations New mib defintions can be created to address the gaps mentioned in the 5.6.1 Gap Analysis section. 6. An Introduction to the MPLS-TP MIB Modules This section highlights new MIB modules that have been identified as being required for MPLS-TP. This section also provides an overview of the following: - the MPLS Object Identifier (OID) tree structure and the position of different MPLS related MIB modules on this tree; - the purpose of each of the MIB modules within the MIB documents, what it can be used for, and how it relates to the other MIB modules. Note that each new MIB module (apart from Textual Conventions modules) will contain one or more Compliance Statements to indicate which objects must be suppor in what manner to claim a specific level of compliance. Additional text, either in the documents that define the MIB modules or in separate Applicability Statements, will define which Compliance Statements need tbe conformed to in order to provide specific MPLS-TP function. This document does not set any requirements in that respect although some recommendations are included in the sections that follow. 6.1 MPLS-TP MIB Modules 6.1.1 Structure of the MPLS-TP MIB OID Tree The MPLS-TP MIB OID tree has the following structure. transmission -- RFC 2578 [RFC2578] | +- mplsStdMIB | +- Textual Conventions for MPLS-TP | +- Identifiers for MPLS-TP | +- LSR MIB Extensions for MPLS-TP | +- TE MIB Extensions for MPLS-TP King & Venkatesan, et al. [Page 17] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 Note that the mib modules mentioned here are applicable for MPLS operations as well. Note: The OIDs for MIB modules are yet to be assigned and managed by IANA. 6.1.2 Textual Conventions for MPLS-TP New textual convention mib module defines textual conventions [RFC2579] for MPLS-TP related MIB modules. These conventions allow multiple MIB modules to use the same syntax and format for a concept that is shared between the MIB modules. For example, MEP identifier is used to identify maintenance entity group end point within MPLS-TP networks. The textual convention representing the MEP identifier is defined in new textual convention mib module. All new extensions related to MPLS-TP are defined in the MIB module and will be referenced by other MIB modules to support MPLS-TP. 6.1.3 Identifiers for MPLS-TP New Identifiers describe managed objects that are used to model common MPLS-TP identifiers [MPLS-TP-IDENTIFIERS]. 6.1.4 LSR MIB Extensions for MPLS-TP MPLS-LSR-STD-MIB describes managed objects for modeling an MPLS Label Switching Router (LSR). This puts it at the heart of the management architecture for MPLS. In the case of MPLS-TP, the MPLS-LSR-STD-MIB is extended to support the MPLS-TP LSP's, which are corouted or associated bidirectional. This extended MIB is also applicable for modeling MPLS-TP tunnels. 6.1.5 Tunnel Extensions for MPLS-TP MPLS-TE-STD-MIB describes managed objects that are used to model and manage MPLS Traffic Engineered (TE) Tunnels. MPLS-TP tunnels are much similar to MPLS-TE tunnels, but are bidirectional and could be co-routed or associated. The MPLS-TE-STD-MIB is extended to support the MPLS-TP specific attributes for the tunnel. 6.2 PWE3 MIB Modules for MPLS-TP King & Venkatesan, et al. [Page 18] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 This section provides an overview of Pseudowire extension mib modules to meet the MPLS based transport network requirements. 6.2.1 Structure of the PWE3 MIB OID Tree for MPLS-TP mib-2 -- RFC 2578 [RFC2578] | +-transmission | | | +- Pseudowire Extensions for MPLS-TP | +- Pseudowire MPLS Extensions for MPLS-TP | +- Pseudowire Textual Conventions for MPLS-TP Note: The OIDs for MIB modules are yet to be assigned and managed by IANA. 6.2.2 Pseudowire Textual Conventions for MPLS-TP PW-TC-STD-MIB MIB defines textual conventions used for pseudowire (PW) technology and for Pseudowire Edge-to-Edge Emulation (PWE3) MIB Modules. New textual convention mib module defines textual definitions for MPLS-TP specific Pseudowire attributes. 6.2.3 Pseudowire Extensions for MPLS-TP PW-STD-MIB describes managed objects for modeling of Pseudowire Edge-to-Edge services carried over a general Packet Switched Network. This MIB module is extended to support MPLS-TP specific attributes related to Pseudowires. 6.2.4 Pseudowire MPLS Extensions for MPLS-TP PW-MPLS-STD-MIB defines the managed objects for Pseudowire operations over MPLS LSR's. This MIB supports both, manual and dynamically signaled PW's, point-to-point connections, enables the use of any emulated service, MPLS-TE as outer tunnel and no outer tunnel as MPLS-TE. The newly extended MIB defines the managed objects, extending PW-MPLS-STD-MIB, by supporting with or without MPLS-TP as outer tunnel. 6.3 OAM MIB Modules for MPLS-TP This section provides an overview of Operations, Administration, and Maintenance (OAM) mib modules for MPLS LSPs and Pseudowires. 6.3.1 Structure of the OAM MIB OID Tree for MPLS-TP King & Venkatesan, et al. [Page 19] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 mib-2 -- RFC 2578 [RFC2578] | +-transmission | +- LSP Ping MIB module | +- BFD MIB module | +- OAM MIB module Note: The OIDs for MIB modules are yet to be assigned and managed by IANA. 6.3.2 LSP Ping MIB module LSP ping is defined in [RFC4379] to validate data plane consistency of MPLS LSP's. It defines how LSP ping and Trace Route could be performed across MPLS networks to identify and diagnose faults within MPLS networks. This OAM functionality is performed on demand basis for verification purposes. New mib module defines managed objects for modeling LSP ping protocol. It allows user to perform on demand operations based on [RFC4379]. For example, a MPLS-TP tunnel LSP is to be pinged, a SNMP request issued using the MIB for the tunnel in test. The results for the operation could be queried using the managed objects defined in the MIB module. 6.3.3 BFD MIB module BFD-STD-MIB defines managed objects for performing BFD operation in IP networks. This MIB is modeled to support BFD protocol [RFC5880]. New mib module is an extension to BFD-STD-MIB managed objects to support BFD operations on MPLS LSPs and PWs. 6.3.4 Common OAM MIB modules New mib module defines managed objects for OAM maintenance identifiers i.e. Maintenance Entity Group Identifiers (MEG), Maintenance Entity Group End-point (MEP), Maintenance Entity Group Intermediate Point (MIP). Maintenance points are uniquely associated with a MEG. Within the context of a MEG, MEPs and MIPs must be uniquely identified. 6.4. Protection Switching and Recovery MIB Modules for MPLS-TP This section provides an overview of protection switching and recovery MIB modules for MPLS LSPs and Pseudowires. King & Venkatesan, et al. [Page 20] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 6.4.1 Structure of the MPLS Protection Switching and Recovery MIB OID Tree for MPLS-TP mib-2 -- RFC 2578 [RFC2578] | +-transmission | +- Linear Protection Switching MIB module | +- Ring Protection Switching MIB module | +- Mesh Protection Swithcing MIB module Note: The OIDs for MIB modules are yet to be assigned and managed by IANA. 6.4.2 Linear Protection Switching MIB module New mib module defines managed objects for linear protection switching of MPLS LSPs and Pseudowires. 6.4.3 Ring Protection Switching MIB module New mib module defines managed objects for ring protection switching of MPLS LSPs and Pseudowires. 6.4.4 Mesh Protection Switching MIB module New mib module defines managed objects for Mesh protection switching of MPLS LSPs and Pseudowires. 7. Management Options This document applies only to scenarios where MIB modules are used to manage the MPLS-TP network. It is not the intention of this document to provide instructions or advice to implementers of management systems, management agents, or managed entities. It is, however, useful to make some observations about how the MIB modules described above might be used to manage MPLS systems, if SNMP is used in the management interface. For MPLS specific management options, refer [RFC4221] Section 12 (Management Options). 8. Security Considerations King & Venkatesan, et al. [Page 21] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 This document describes the interrelationships amongst the different MIB modules relevant to MPLS-TP management and as such does not have any security implications in and of itself. Each IETF MIB document that specifies MIB objects for MPLS-TP must provide a proper security considerations section that explains the security aspects of those objects. The attention of readers is particularly drawn to the security implications of making MIB objects available for create or write access through an access protocol such as SNMP. SNMPv1 by itself is an insecure environment. Even if the network itself is made secure (for example, by using IPSec), there is no control over who on the secure network is allowed to access the objects in this MIB. It is recommended that the implementers consider the security features as provided by the SNMPv3 framework. Specifically, the use of the User-based Security Model STD 62, RFC3414 [RFC3414], and the View-based Access Control Model STD 62, RFC 3415 [RFC3415], is recommended. It is then a customer/user responsibility to ensure that the SNMP entity giving access to an instance of each MIB module is properly configured to give access to only those objects, and to those principals (users) that have legitimate rights to access them. 9. IANA Considerations This document makes no requests for IANA action. 10. Acknowledgements The authors would like to thank Eric Gray, Thomas Nadeau, Benjamin Niven-Jenkins and Saravanan Narasimhan for their valuable comments. This document benefited from review by participants in ITU-T Study Group 15. 11. References 11.1 Normative References [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB using SMIv2", RFC 2863, June 2000. [RFC3811] Nadeau, T. and J. Cucchiara, "Definition of Textual Conventions and for Multiprotocol Label Switching (MPLS) Management", RFC 3811, June 2004. King & Venkatesan, et al. [Page 22] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 [RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau, "Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) Management Information Base (MIB)", RFC 3812, June 2004. [RFC3813] Srinivasan, C., Viswanathan, A., and T. Nadeau, "Multiprotocol Label Switching (MPLS) Label Switching (LSR) Router Management Information Base (MIB)", RFC 3813, June 2004. [RFC3814] Nadeau, T., Srinivasan, C., and A. Viswanathan, "Multiprotocol Label Switching (MPLS) FEC-To-NHLFE (FTN) Management Information Base", RFC3814, June 2004. [RFC3815] Cucchiara, J., Sjostrand, H., and Luciani, J., "Definitions of Managed Objects for the Multiprotocol Label Switching (MPLS), Label Distribution Protocol (LDP)", RFC 3815, June 2004. [RFC4220] Dubuc, M., Nadeau, T., and J. Lang, "Traffic Engineering Link Management Information Base", RFC 4220, November 2005. [RFC4221] Nadeau, T., Srinivasan, C., and A. Farrel, "Multiprotocol Label Switching (MPLS) Management Overview", RFC 4221, November 2005. [RFC4801] T. Nadeau and A. Farrel, Ed., "Definitions of Textual Conventions for Generalized Multiprotocol Label Switching (GMPLS) Management", RFC4801, Feb. 2007. [RFC4802] T. D. Nadeau and A. Farrel, "Generalized Multiprotocol Label Switching (GMPLS) Traffic Engineering Management Information Base", RFC4802, Feb., 2007. [RFC4803] T. D. Nadeau and A. Farrel, "Generalized Multiprotocol Label Switching (GMPLS) Label Switching Router (LSR) Management Information Base", RFC4803, Feb., 2007. [RFC5542] Nadeau, T., Ed., Zelig, D., Ed., and O. Nicklass, Ed., "Definitions of Textual Conventions for Pseudowire (PW) Management", RFC 5542, May 2009. [RFC5601] Nadeau, T., Ed. and D. Zelig, Ed. "Pseudowire (PW) Management Information Base (MIB)", RFC 5601, July 2009. [RFC5602] Zelig, D., Ed., and T. Nadeau, Ed., "Pseudowire (PW) over MPLS PSN Management Information Base (MIB)", RFC 5602, July 2009. King & Venkatesan, et al. [Page 23] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 [RFC5603] Zelig, D., Ed., and T. Nadeau, Ed., "Ethernet Pseudowire (PW) Management Information Base (MIB)", RFC 5603, July 2009. [RFC5604] Nicklass, O., "Managed Objects for Time Division Multiplexing (TDM) over Packet Switched Networks (PSNs)", RFC5604, July 2009. 11.2 Informative References [RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. [RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999. [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999. [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, March 2001. [RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction and Applicability Statements for Internet-Standard Management Framework", RFC 3410, December 2002. [RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", STD 62, RFC 3414, December 2002. [RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3415, December 2002. [RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau, "Multiprotocol Label Switching (MPLS) Traffic Engineering (TE) Management Information Base (MIB)", RFC 3812, June 2004. [RFC3813] Srinivasan, C., Viswanathan, A., and T. Nadeau, "Multiprotocol Label Switching (MPLS) Label Switching Router (LSR) Management Information Base (MIB)", RFC 3813, June 2004. King & Venkatesan, et al. [Page 24] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 [RFC3931] Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005. [RFC3945] Mannie, E. et.al., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", IETF RFC 3945, October 2004. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC4197] Riegel, M., "Requirements for Edge-to-Edge Emulation of Time Division Multiplexed (TDM) Circuits over Packet Switching Networks", RFC4197, October 2005. [RFC4377] Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S. Matsushima, "Operations and Management (OAM) Requirements for Multi-Protocol Label Switched (MPLS) Networks", RFC 4377, March 2006. [RFC4378] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol Label Switching (MPLS) Operations and Management (OAM)", RFC 4378, March 2006. [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, March 2006. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007. [RFC5601] Nadeau, T., Ed. and D. Zelig, Ed. "Pseudowire (PW) Management Information Base (MIB)", RFC 5601, July 2009. [RFC5602] Zelig, D., Ed., and T. Nadeau, Ed., "Pseudowire (PW) over MPLS PSN Management Information Base (MIB)", RFC 5602, July 2009. [RFC5654] Niven-Jenkins, B., et al, "MPLS-TP Requirements", RFC5654, September 2009. [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection", RFC 5880, June 2010. King & Venkatesan, et al. [Page 25] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "Bidirectional Forwarding Detection (BFD) For MPLS Label Switched Paths (LSPs)", RFC 5884, June 2010. [RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", RFC5885, June 2010. [RFC5950] Gray, E., Mansfield, S., Lam, K., "MPLS-TP Network Management Framework", RFC 5950, September 2010. [RFC5951] Gray, E., Mansfield, S., Lam, K., "MPLS TP Network Management Requirements", RFC 5951, September 2010. [MPLS-TP-IDENTIFIERS] Bocci, M., Swallow, G., "MPLS-TP Identifiers" draft-ietf-mpls-tp-identifiers-04, March 2011. [MPLS-TP-OAM-FWK] Busi, I. and B. Niven-Jenkins, "MPLS-TP OAM Framework and Overview", 2009, . 12. Authors' Addresses Adrian Farrel Old Dog Consulting UK Email: adrian@olddog.co.uk Daniel King Old Dog Consulting UK Email: daniel@olddog.co.uk Venkatesan Mahalingam Aricent India Email: venkatesan.mahalingam@aricent.com Scott Mansfield Ericsson 300 Holger Way, San Jose, CA 95134, US Phone: +1 724 931 9316 Email: scott.mansfield@ericsson.com King & Venkatesan, et al. [Page 26] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011 Jeong-dong Ryoo ETRI 161 Gajeong, Yuseong, Daejeon, 305-700, South Korea Phone: +82 42 860 5384 Email: ryoo@etri.re.kr A S Kiran Koushik Cisco Systems Inc. Email: kkoushik@cisco.com A. Karmakar Cisco Systems Inc. Email: akarmaka@cisco.com Sam Aldrin Huawei Technologies, co. 2330 Central Express Way, Santa Clara, CA 95051, USA Email: aldrin.ietf@gmail.com King & Venkatesan, et al. [Page 27] draft-ietf-mpls-tp-mib-management-overview-04.txt June 2011