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INFORMATIONAL
Network Working Group                                          T. NadeauRequest for Comments: 4221                           Cisco Systems, Inc.Category: Informational                                    C. Srinivasan                                                          Bloomberg L.P.                                                               A. Farrel                                                      Old Dog Consulting                                                           November 2005Multiprotocol Label Switching (MPLS) Management OverviewStatus of This Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2005).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.   This document describes the management architecture for MPLS and   indicates the interrelationships between the different MIB modules   used for MPLS network management.Table of Contents1. Introduction ....................................................32. Terminology .....................................................33. The SNMP Management Framework ...................................34. An Introduction to the MPLS Working Group MIB Modules ...........44.1. Structure of the MPLS MIB OID Tree .........................54.2. MPLS-TC-STD-MIB ............................................54.3. MPLS-LSR-STD-MIB ...........................................54.4. MPLS-LDP-STD-MIB ...........................................64.5. MPLS-LDP-GENERIC-STD-MIB ...................................64.6. MPLS-LDP-ATM-STD-MIB .......................................64.7. MPLS-LDP-FRAME-RELAY-STD-MIB ...............................74.8. MPLS-TE-STD-MIB ............................................74.9. MPLS-FTN-STD-MIB ...........................................7Nadeau, et al.               Informational                      [Page 1]

RFC 4221                MPLS Management Overview           November 20054.10. TE-LINK-STD-MIB ...........................................74.11. MIB Module Interdependencies ..............................84.12. Dependencies on External MIB Modules ......................95. Tables, Scalars, and Notifications in MPLS-LSR-STD-MIB .........105.1. Tables ....................................................105.2. Scalars ...................................................105.3. Indexing ..................................................115.4. Notifications .............................................125.5. Dependencies between MIB Module Tables ....................126. Tables, Scalars, and Notifications in the LDP MIB ..............136.1. MIB Modules ...............................................136.2. Tables ....................................................146.3. Scalars ...................................................156.4. Notifications .............................................156.5. Dependencies between MIB Module Tables ....................157. Tables, Scalars, and Notifications in MPLS-TE-STD-MIB ..........167.1. Tables ....................................................167.2. Scalars ...................................................177.3. Notifications .............................................187.4. Dependencies between MIB Module Tables ....................188. Tables, Scalars, and Notifications in MPLS-FTN-STD-MIB .........188.1. Tables ....................................................188.2. Scalars ...................................................198.3. Notifications .............................................198.4. Dependencies between MIB Module Tables ....................199. Tables and Objects in TE-LINK-STD-MIB ..........................199.1. Tables ....................................................199.2. Scalars ...................................................209.3. Notifications .............................................209.4. Dependencies between MIB Module Tables ....................2010. Table Dependencies between MPLS MIB Modules ...................2111. A Note on Interfaces ..........................................2111.1. MPLS Tunnels as Interfaces ...............................2111.2. Application of the Interfaces Group to TE Links ..........22      11.3. References to Interface MIB Objects from MPLS MIB            Modules ..................................................2312. Management Options ............................................2413. Related IETF MIB Modules ......................................2513.1. PWE3 Working Group MIB Modules ...........................2613.2. PPVPN Working Group MIB Modules ..........................2613.2.1. PPVPN-MPLS-VPN-STD-MIB ............................2613.3. CCAMP Working Group MIB Modules ..........................2614. Traffic Engineering Working Group TE MIB ......................2714.1. Choosing between TE MIB Modules ..........................2715. Security Considerations .......................................2816. Acknowledgements ..............................................2817. Normative References ..........................................2918. Informative References ........................................30Nadeau, et al.               Informational                      [Page 2]

RFC 4221                MPLS Management Overview           November 20051.  Introduction   This document describes the Management Architecture for Multi-   Protocol Label Switching (MPLS) [RFC3031].  In particular, it   describes how the managed objects defined in various MPLS-related   Management Information Base (MIB) documents model different aspects   of MPLS.  Furthermore, this document explains the interactions and   dependencies between each of these MIB modules.   For additional information, this document also includes a brief note   on MIB modules produced by the Pseudo Wire Emulation Edge to Edge   (PWE3), Provider Provisioned Virtual Private Network (PPVPN), Common   Control and Measurement Plane (CCAMP), and Internet Traffic   Engineering (TEWG) working groups.   The document begins with a brief outline of the SNMP framework.  This   is not intended to be a complete reference on SNMP, but is provided   to give context to the rest of the document and to indicate reference   material for readers that need to know more about SNMP.   This document does not propose any additions to the MPLS MIB   framework, nor define any standards for the Internet community.  It   is an informational document.  In all cases, the reader is advised to   turn to the document that defines the MIB module in question for   further information.   Comments should be made directly to the MPLS mailing list at   mpls@uu.net.2.  Terminology   This document uses terminology from the MPLS architecture document   [RFC3031] and the following MPLS related MIB modules: MPLS TC MIB   [TCMIB], MPLS LSR MIB [LSRMIB], MPLS TE MIB [TEMIB], MPLS LDP MIB   [LDPMIB], MPLS FTN MIB [FTNMIB], TE LINK MIB [TELMIB], and PPVPN MPLS   VPN MIB [VPNMIB].   Throughout this document hyphenated MIB names (such as MPLS-TE-STD-   MIB) should be taken to refer to specific MIB modules.  Non-   hyphenated MIB names (such as MPLS LDP MIB) indicate MIB documents.3.  The SNMP Management Framework   For a detailed overview of the documents that describe the current   Internet-Standard Management Framework, please refer tosection 7 of   RFC 3410 [RFC3410].Nadeau, et al.               Informational                      [Page 3]

RFC 4221                MPLS Management Overview           November 2005   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).  This document specifies a   MIB module that is compliant to the SMIv2, which is described in STD   58,RFC 2578 [RFC2578], STD 58,RFC 2579 [RFC2579] and STD 58,RFC2580 [RFC2580].4.  An Introduction to the MPLS Working Group MIB Modules   This section addresses the MIB documents produced by the MPLS working   group, namely MPLS TC MIB, MPLS LSR MIB, MPLS TE MIB, MPLS LDP MIB,   MPLS FTN MIB, and TE LINK MIB.  The rest of this section briefly   describes 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 MIB document contains one or more compliance   statements for the modules and objects that it defines.  Therefore,   the support for the different MIB modules and objects is beyond the   scope of this document, although some recommendations are included in   the sections that follow.Nadeau, et al.               Informational                      [Page 4]

RFC 4221                MPLS Management Overview           November 20054.1.  Structure of the MPLS MIB OID Tree   The MPLS MIB OID tree has the following structure.      transmission --RFC 2578 [RFC2578]        |        +- mplsStdMIB -- MPLS-TC-STD-MIB        |    |        |    +- mplsTCStdMIB -- MPLS-TC-STD-MIB        |    |        |    +- mplsLsrStdMIB -- MPLS-LSR-STD-MIB        |    |        |    +- mplsTeStdMIB -- MPLS-TE-STD-MIB        |    |        |    +- mplsLdpStdMIB -- MPLS-LDP-STD-MIB        |    |        |    +- mplsLdpAtmStdMIB -- MPLS-LDP-ATM-STD-MIB        |    |        |    +- mplsLdpFrameRelayStdMIB -- MPLS-LDP-FRAME-RELAY-STD-MIB        |    |        |    +- mplsLdpGenericStdMIB -- MPLS-LDP-GENERIC-STD-MIB        |    |        |    +- mplsFTNStdMIB -- MPLS-FTN-STD-MIB        |        +- teLinkStdMIB -- TE-LINK-STD-MIB   Note: The OIDs for MIB modules are assigned and managed by IANA.   They can be found in the referenced MIB documents.4.2.  MPLS-TC-STD-MIB   MPLS-TC-STD-MIB defines textual conventions [RFC2579] that may be   common to MPLS-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, labels are a central part of MPLS and need to be   presented in many of the MIB modules.  The textual convention for   representing an MPLS label is defined in MPLS-TC-STD-MIB.   All of the other MPLS MIB modules import textual conventions from   this MIB module.4.3.  MPLS-LSR-STD-MIB   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.Nadeau, et al.               Informational                      [Page 5]

RFC 4221                MPLS Management Overview           November 2005   This MIB module is used to model and manage the basic label switching   behavior of an MPLS LSR.  It represents the label forwarding   information base (LFIB) of the LSR and provides a view of the LSPs   that are being switched by the LSR in question.   Since basic MPLS label switching is common to all MPLS applications,   this MIB module is referenced by many of the other MPLS MIB modules.   In general, MPLS-LSR-STD-MIB provides a model of incoming labels on   MPLS-enabled interfaces being mapped to outgoing labels on MPLS-   enabled interfaces via a conceptual object called an MPLS cross-   connect.  MPLS cross-connect entries and their properties are   represented in MPLS-LSR-STD-MIB and are typically referenced by other   MIB modules in order to refer to the underlying MPLS LSP.   For example, MPLS-TE-STD-MIB models traffic-engineered tunnels.   These tunnels map to one or more underlying MPLS LSPs.  MPLS-TE-STD-   MIB refers to the underlying LSPs by pointing to cross-connect   entries in MPLS-LSR-STD-MIB.4.4.  MPLS-LDP-STD-MIB   MPLS-LDP-STD-MIB describes managed objects used to model and manage   the MPLS Label Distribution Protocol (LDP) [RFC3036].  LDP is one of   the MPLS protocols used to distribute labels and establish LSPs.   This MIB module contains objects common to all LDP implementations.   For an LDP implementation that provides standard MIB support, this   MIB module provides the core set of objects that are needed, along   with one or more of the other LDP MIB modules from the following   sections.4.5.  MPLS-LDP-GENERIC-STD-MIB   This MIB module provides objects for managing the LDP Per Platform   Label Space and is typically implemented along with the MPLS-LDP-   STD-MIB module.  This MIB Module contains tables for configuring MPLS   Generic Label Ranges.  Although the LDP Specification does not   provide a way to configure Label Ranges for Generic Labels, the MIB   module does provide a way to reserve a range of generic labels   because the working group thought this was useful.4.6.  MPLS-LDP-ATM-STD-MIB   This MIB module is typically supported along with MPLS-LDP-STD-MIB by   LDP implementations if LDP uses ATM as the Layer 2 medium.  Tables in   this MIB module allow for configuring LDP to use ATM.Nadeau, et al.               Informational                      [Page 6]

RFC 4221                MPLS Management Overview           November 20054.7.  MPLS-LDP-FRAME-RELAY-STD-MIB   This MIB module is typically supported along with MPLS-LDP-STD-MIB by   LDP implementations if LDP uses Frame Relay as the Layer 2 medium.   Tables in this MIB module allow for configuration of LDP to use Frame   Relay.4.8.  MPLS-TE-STD-MIB   MPLS-TE-STD-MIB describes managed objects that are used to model and   manage MPLS Traffic Engineered (TE) Tunnels.   This MIB module is based on a table that represents TE tunnels that   either originate from, traverse via, or terminate on the LSR in   question.  The MIB module provides configuration and statistics   objects needed for TE tunnels.4.9.  MPLS-FTN-STD-MIB   MPLS-FTN-STD-MIB describes managed objects that are used to model and   manage the MPLS FEC-to-NHLFE (FTN) mappings that take place at an   ingress Label Edge Router (LER).   An LER is an LSR placed at the edge of an MPLS domain, and it passes   traffic into and out of the MPLS domain.  An ingress LER is   responsible for classifying data and assigning it to a suitable LSP   or tunnel.   This classification is done using Forwarding Equivalence Classes   (FECs) that define the common attributes of data (usually packets)   that will be treated in the same way.  Once data has been classified,   it can be handed off to an LSP or tunnel through the Next Hop Label   Forwarding Entry (NHLFE).   In the case of an IP-to-MPLS mapping, the FEC objects describe IP   6-tuples that represent source and destination address ranges, source   and destination port ranges, the IPv4 Protocol field or IPv6 next-   header field, and the DiffServ Code Point (DSCP).4.10.  TE-LINK-STD-MIB   TE-LINK-STD-MIB describes managed objects that are used to model and   manage TE links, including bundled links, in an MPLS network.   The TE link feature is designed to aggregate one or more similar data   channels or TE links between a pair of LSRs.  A TE link is a sub-   interface capable of carrying traffic-engineered MPLS traffic.Nadeau, et al.               Informational                      [Page 7]

RFC 4221                MPLS Management Overview           November 2005   A bundled link is a sub-interface that bonds the traffic of a group   of one or more TE links.4.11.  MIB Module Interdependencies   This section provides an overview of the relationship between the   MPLS MIB modules described above.  More details of these   relationships are given below after the MIB modules have been   discussed in more detail.   The arrows in the following diagram show a 'depends on' relationship.   A relationship "MIB module A depends on MIB module B" means 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.   +-------> MPLS-TC-STD-MIB   |            ^   |            |   |         MPLS-LSR-STD-MIB <------------------+   |                                             |   +<----------------------- MPLS-LDP-STD-MIB -->+   |                                    ^        |   |                                    |        |   +<-- MPLS-LDP-GENERIC-STD-MIB ------>+        |   |                                    |        |   +<-- MPLS-LDP-ATM-STD-MIB ---------->+        |   |                                    |        |   +<-- MPLS-LDP-FRAME-RELAY-STD-MIB -->+        |   |                                             |   +<------- MPLS-TE-STD-MIB ------------------->+   |            ^                                |   |            |                                |   +<------- MPLS-FTN-STD-MIB ------------------>+   Thus:   -  All the MPLS MIB modules depend on MPLS-TC-STD-MIB.   -  MPLS-LDP-STD-MIB, MPLS-TE-STD-MIB, and MPLS-FTN-STD-MIB contain      references to objects in MPLS-LSR-STD-MIB.   -  MPLS-LDP-GENERIC-STD-MIB, MPLS-LDP-ATM-STD-MIB, and MPLS-LDP-      FRAME-RELAY-STD-MIB contain references to objects in MPLS-LDP-      STD-MIB.   -  MPLS-FTN-STD-MIB contains references to objects in MPLS-TE-STD-      MIB.Nadeau, et al.               Informational                      [Page 8]

RFC 4221                MPLS Management Overview           November 2005   Note that there is a textual convention (MplsIndexType) defined in   MPLS-LSR-STD-MIB that is imported by MPLS-LDP-STD-MIB.4.12.  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].   Additionally, MPLS-LDP-ATM-STD-MIB imports the textual convention   AtmVpIdentifier from ATM-TC-MIB to represent an ATM virtual path   identifier, whereas MPLS-LDP-FRAME-RELAY-STD-MIB imports the textual   convention DLCI from FRAME-RELAY-DTE-MIB to represent a Data Link   Channel identifier.   MPLS-LDP-STD-MIB imports the textual conventions IndexInteger and   IndexIntegerNextFree from [RFC3289], and MPLS-TE-STD-MIB imports   IndexIntegerNextFree.  IndexInteger provides a standard arbitrary   index, whereas IndexIntegerNextFree is used by a management agent   that needs to select an appropriate value for an arbitrary index.   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.  This is business as usual for a MIB module   and is not discussed further in this document.Nadeau, et al.               Informational                      [Page 9]

RFC 4221                MPLS Management Overview           November 20055.  Tables, Scalars, and Notifications in MPLS-LSR-STD-MIB5.1.  Tables   MPLS-LSR-STD-MIB contains the following tables.   -  The interface configuration table (mplsInterfaceTable) is used for      enabling MPLS on MPLS-capable interfaces.   -  The in-segment (mplsInSegmentTable) and out-segment      (mplsOutSegmentTable) tables are used to configure and monitor LSP      segments carrying data into and out of the LSR, respectively.   -  The in-segment mapping table (mplsInSegmentMapTable) provides a      look-up table that enables the discovery of an in-segment in      mplsInSegmentTable from the known incoming interface and incoming      label.   -  The cross-connect table (mplsXCTable) is used to associate in and      out segments in order to form a cross-connect (i.e., to represent      an LSP transiting the LSR).   -  The label stack table (mplsLabelStackTable) allows the      specification of multi-label stacks to be imposed on a given LSP      at this LSR.   -  The MPLS in-segment (mplsInSegmentPerfTable) and out-segment      (mplsOutSegmentPerfTable) performance tables contain objects to      measure the performance of LSPs.   -  The MPLS interface performance table (mplsInterfacePerfTable) has      objects to measure MPLS performance on a per-interface basis.5.2.  Scalars   Where tables in the MIB module have arbitrary indexes, scalars are   provided to supply the next available index.  This applies to   mplsInSegmentTable, mplsOutSegmentTable, mplsXCTable, and   mplsLabelStackTable, but see the section on indexing, below.   mplsMaxLabelStackDepth defines the maximum size of a imposed label   stack supported at this LSR (and not, as the description in MPLS-   LSR-STD-MIB states, the maximum label stack depth supported by the   LSR).   mplsXCNotificationsEnable is used to enable and disable notifications   from MPLS-LSR-STD-MIB.Nadeau, et al.               Informational                     [Page 10]

RFC 4221                MPLS Management Overview           November 20055.3.  Indexing   Note that the indexing used by the tables in MPLS-LSR-STD-MIB is   unusual.  A specific textual convention, MplsIndexType, is defined in   the MIB module and is used as the type for indexes to   mplsInSegmentTable, mplsOutSegmentTable, mplsXCTable, and   mplsLabelStackTable.  The textual convention is defined as an octet   string of between one and twenty-four octets, inclusive.   Although this convention can be used to map simple integers and so   preserve the normal indexing techniques, it may also be used to   encode more complex indexing rules that may be useful to   implementations that subdivide their label spaces according to   physical or implementation constraints (such as placing the   responsibility for a subset of labels with a line card).   Note that it would be unusual, but not impossible, to make   sophisticated use of these indexes in a write-access MIB since the   'next' index value would be hard to determine.  Thus, non-simple   values are likely only to be used in read-only MIBs in which the   indexes are generated as a result of signaling protocol   implementations or other configuration means.  The formatting and   interpretation of non-simple indexes is out of the scope of the MIB   module definition and is expected to be part of the manageability   statement for a particular device.  When the formatting is not known   by an agent, it should treat the index as a plain octet string   containing an integer of between one and twenty-four octets.   As described in the previous section, scalars are provided to allow   agents to discover a suitable value to use as an index when creating   a new row in one of these tables.  These scalars all use a second   textual convention, MplsIndexNextType, also defined within MPLS-LSR-   STD-MIB.  This textual convention allows the 'null string', (that is,   a string of length one octet with value 0x00).  The null string is   used to indicate that either write access is not supported or no more   indexes are currently available.   Note that the usage of the nextIndex scalars is such that at any time   a scalar supplies a value that is currently unused as an index to the   specific table.  In order to avoid lacunae in the indexing of a table   under normal usage, implementations are recommended to change the   value in an nextIndex scalar only when the index is used (that is,   when a row is created) and not when the nextIndex scalar is read.  In   a 'busy' table, this may result in row creation attempts failing and   agents having to re-read the scalar before making a second row   creation attempt.  The desire to avoid this issue is in opposition to   the desire to avoid lacunae.Nadeau, et al.               Informational                     [Page 11]

RFC 4221                MPLS Management Overview           November 20055.4.  Notifications   MPLS-LSR-STD-MIB can issue two notifications (if notifications are   enabled).   -  mplsXCUp reports when a cross-connect becomes active.   -  mplsXCDown reports when a cross-connect becomes      inactive.5.5.  Dependencies between MIB Module Tables   The tables in MPLS-LSR-STD-MIB are related as shown on the diagram   below.  The arrows indicate a reference from one table to another.   Note that the various MIB tables contain two instances of pointers to   external tables that are not currently defined.  Entries in an   external Traffic Parameters Table (external_Traffic_Table) are   pointed to using RowPointers from the mplsInSegmentTable   (mplsInSegmentTrafficParamPtr) and from the mplsOutSegmentTable   (mplsOutSegmentTrafficParamPtr) to allow representation of the   traffic parameters for the MPLS segment.  Alternatively, the pointers   may indicate an entry in the Tunnel Resource Table   (mplsTunnelResourceTable) in MPLS-TE-STD-MIB.  Similarly, an external   label table may be used to store label values if, for some reason,   they are not stored in place within the LSR MIB tables.  This might   occur if extra per-label space information needs to be stored, and it   paves the way for GMPLS where labels cannot always be stored in a   32-bit value.  RowPointers are used from the mplsInSegmentTable   (mplsInSegmentLabelPtr), the mplsOutSegmentTable   (mplsOutSegmentTopLabelPtr), and from the mplsLabelStackTable   (mplsLabelStackLabelPtr).Nadeau, et al.               Informational                     [Page 12]

RFC 4221                MPLS Management Overview           November 2005                      mplsInterfacePerfTable                                 ^                                 |                                 V                        mplsInterfaceTable                         ^              ^   mplsInSegmentMapTable |              | mplsLabelStackTable             |           |              |           ^     |             |      +----+              +----+      |     |             |      |                        |      |     |             |      | external_Traffic_Table |      |     |             |      |   ^                ^   |      |     |             V      |   |                |   |      |     |            mplsInSegmentTable        mplsOutSegmentTable |             |  ^   ^                        ^   ^     |  |             |  |   |                        |   |     |  V      +------+  |   +----> mplsXCTable  <----+   |     +--+      |         V                                V        |      | mplsInSegmentPerfTable    mplsOutSegmentPerfTable |      |                                                   |      +--------------> external_Label_Table <-------------+6. Tables, Scalars, and Notifications in the LDP MIB6.1.  MIB Modules   The MIB document for LDP contains four MIB modules.  This structure   makes it easier for an implementation to select only those modules   that are relevant to it.  The MIB Modules are MPLS-LDP-STD-MIB,   MPLS-LDP-GENERIC-STD-MIB, MPLS-LDP-ATM-STD-MIB, and MPLS-LDP-FRAME-   RELAY-STD-MIB.   MPLS-LDP-STD-MIB defines objects that are specific to LDP without any   Layer 2 objects.  MPLS-LDP-GENERIC-STD-MIB defines Layer 2 Per   Platform Label Space objects for use with MPLS-LDP-STD-MIB and for   use on Ethernet.  MPLS-LDP-ATM-STD-MIB defines Layer 2 Asynchronous   Transfer Mode (ATM) objects for use with MPLS-LDP-STD-MIB.  MPLS-   LDP-FRAME-RELAY-STD-MIB defines Layer 2 FRAME-RELAY objects for use   with MPLS-LDP-STD-MIB.   The MPLS-LDP-STD-MIB module provides the core support and is   typically supported along with at least one of the Layer 2 MIB   modules.Nadeau, et al.               Informational                     [Page 13]

RFC 4221                MPLS Management Overview           November 20056.2.  Tables   The tables in the LDP MIB for configuring the LDP behavior of an LSR   are as follows.   -  The LDP Entity Table (mplsLdpEntityTable) provides a way to      configure the LSR for using LDP.  There must be at least one LDP      Entity for the LSR to support LDP.  Each entry/row in this table      represents a single LDP Entity.   -  Several tables exist to help configure LDP's use of labels.  These      are spread through the MIB modules described in the previous      section.  They are: mplsLdpEntityGenLRTable,      mplsLdpEntityAtmParmsTable and mplsLdpEntityAtmLRTable,      mplsLdpEntityFrameRelayParmsTable and mplsLdpEntityFrLRTable.      They are used to configure generic, ATM, and Frame Relay labels as      their names suggest.   -  The LDP Peer Table (mplsLdpPeerTable) is a read-only table that      contains information about LDP Peers known to LDP Entities.   -  The LDP Hello Adjacencies Table (mplsLdpHelloAdjacencyTable) is a      table of all adjacencies between all LDP Entities and all LDP      Peers.   -  Several tables exist to monitor and control LDP sessions.  The LDP      Session Table (mplsLdpSessionTable) represents sessions between an      LDP Entity and a Peer.  mplsLdpAtmSesTable and      mplsLdpFrameRelaySesTable contain session information specific to      ATM.   -  The MPLS LDP Session Peer Address Table (mplsLdpSesPeerAddrTable)      stores addresses learned after session initialization via Address      Message advertisement.   -  The LDP FEC Table (mplsFecTable) represents FEC (Forwarding      Equivalence Class) information that may be in use on one or more      LSPs.  The LDP LSP FEC Table (mplsLdpLspFecTable) shows the FECs      associated with each LSP.   -  MPLS-LDP-STD-MIB has a mapping table (mplsLdpLspTable) that maps      the LDP MIB's representation of LDP sessions to the underlying LSR      MIB's representation of the LSPs created by these sessions, by      pointing to mplsInSegmentTable, mplsOutSegmentTable, and      mplsXCTable, respectively.Nadeau, et al.               Informational                     [Page 14]

RFC 4221                MPLS Management Overview           November 2005   -  Statistics may be gathered through the LDP Entity Statistics Table      (mplsLdpEntityStatsTable) and the LDP Session Statistics Table      (mplsLdpSesStatsTable).6.3.  Scalars   Where tables in the MIB modules have arbitrary indexes, scalars are   provided to supply the next available index.  This applies to   mplsLdpEntityTable and mplsFecTable.   Two scalars exist to configure the LSR.  The LSR ID is set in   mplsLdpLsrId, and the loop detection capabilities are reported in   mplsLdpLsrLoopDetectionCapable.6.4.  Notifications   MPLS-LDP-STD-MIB defines four notifications that a device can issue.   -  mplsLdpInitSesThresholdExceeded is reported when the number of      Session Initialization messages exceeds a configured threshold.   -  mplsLdpPVLMismatch is issued if the Path Vector Limit for a      configured Entity and Peer do not match.   -  mplsLdpSessionUp and mplsLdpSessionDown report the transition of      Session state.   No scalar object is provided to enable and disable notifications from   MPLS-LDP-STD-MIB.  Instead, the implementer is referred to [RFC3413].6.5.  Dependencies between MIB Module Tables   The many tables in the four LDP MIB modules are related as shown on   the diagram below.  The arrows indicate a reference from one table to   another.  Note that in many cases the reference is through an   augmentation of the referenced table.Nadeau, et al.               Informational                     [Page 15]

RFC 4221                MPLS Management Overview           November 2005   mplsLdpEntityGenLRTable ------------->+   mplsLdpEntityAtmParmsTable ---------->+   mplsLdpEntityAtmLRTable ------------->+   mplsLdpEntityFrameRelayParmsTable --->+   mplsLdpEntityFrLRTable -------------->+   mplsLdpEntityStatsTable ------------->+                                         |   mplsLdpHelloAdjacencyTable            |                |                        |                |  mplsLdpEntityTable <--+                |      ^       ^                V      |       |            mplsLdpPeerTable <-+- mplsLdpSesPeerAddrTable                       ^       |                       |       V                 mplsLdpSessionTable                              ^   ^                              |   |   mplsLdpSesStatsTable ------+   +-- mplsLdpLspFecTable   mplsLdpAtmSesTable --------+   |    |       |   mplsLdpFrameRelaySesTable--+   |    |       V                                  |    |    mplsFecTable                                  |    V                                  +-- mplsLdpLspTable7.  Tables, Scalars, and Notifications in MPLS-TE-STD-MIB7.1.  Tables   MPLS-TE-STD-MIB contains the following tables.   -  The Tunnel Table (mplsTunnelTable) is used to configure and report      MPLS tunnels.  Note that reporting of tunnels in this table at      transit LSRs is optional.      Entries in mplsTunnelTable are indexed by four objects.  The      source and destination LSR IDs give context to the entry, and an      index  (mplsTunnelIndex) identifies the tunnel itself.  However,      the fourth index (mplsTunnelInstance) may give rise to some      confusion since its usage is not clearly explained.      The description says: "Uniquely identifies an instance of a      tunnel.  It is useful to identify multiple instances of tunnels      for the purposes of backup and parallel tunnels." In the case of      backup tunnels, multiple instances of the same tunnel may be      defined, but only one is active at any time.  Different instances      may have different properties (such as explicit routes), and one      instance may be set up to protect against failure of another.Nadeau, et al.               Informational                     [Page 16]

RFC 4221                MPLS Management Overview           November 2005      Parallel tunnels may be used to provide load sharing or      protection.      The mplsTunnelInstancePriority object is used to indicate the      precedence of tunnels with the same LSR IDs and mplsTunnelIndex      value.  The mplsTunnelPrimaryInstance object gives a quick      reference back to the preferred instance of the tunnel.      The mplsTunnelIndex value is typically signaled as the Tunnel ID,      and the mplsTunnelInstance as the LSP ID, in protocols where both      fields exist.  In protocols where there is only one identifying      index (usually known as the LSP ID), only the mplsTunnelIndex is      signaled.   -  The Resource Table (mplsTunnelResourceTable) is used to configure      resources to be requested on this tunnel.  The CRLDP resource      table (mplsTunnelCRLDPResTable) is used to request additional      resource details that are specific to tunnels signaled using CR-      LDP.   -  The routes requested, computed, and actually used for a tunnel are      found in the Tunnel Hop Table (mplsTunnelHopTable), Tunnel      Computed Hop Table (mplsTunnelCHopTable), and Tunnel Actual Hop      Table (mplsTunnelARHopTable).   -  Statistics about the performance of tunnels may be gathered      through the Tunnel Performance Table (mplsTunnelPerfTable).7.2.  Scalars   Where tables in the MIB module have arbitrary indexes, scalars are   provided to supply the next available index.  This applies to   mplsTunnelTable, mplsTunnelResourceTable, and mplsTunnelHopTable.   Two scalars exist to configure the support for MPLS tunnels on the   LSR.  mplsTunnelTEDistProto lists the signaling methods and protocols   supported.  mplsTunnelMaxHops defines the size of route that may be   configured on the LSR.   Two further scalars enhance the statistics on the LSR by counting the   number of configured (mplsTunnelConfigured) and active   (mplsTunnelActive) tunnels.   The scalar mplsTunnelNotificationMaxRate is used to control the rate   at which notifications are issued from MPLS-TE-STD-MIB.  A rate of   zero means that notifications must not be issued.  If notificationsNadeau, et al.               Informational                     [Page 17]

RFC 4221                MPLS Management Overview           November 2005   would be generated faster than the configured rate, an implementation   may choose to discard notifications or to queue them for distribution   at a quieter time.7.3.  Notifications   MPLS-TE-STD-MIB defines four notifications that a device can issue.   The rate of dispatch of notifications is controlled as described in   the previous section.   -  mplsTunnelUp and mplsTunnelDown report the transition of Tunnel      state.   -  Rerouting and re-optimization of Tunnels paths are reported by      mplsTunnelRerouted and mplsTunnelReoptimized.7.4.  Dependencies between MIB Module Tables   The tables in MPLS-TE-STD-MIB are related as shown on the diagram   below.  The arrows indicate a reference from one table to another.                        mplsTunnelPerfTable                                ^                                |                                V                         mplsTunnelTable                             |      |                             V      |        mplsTunnelResourceTable     +--> mplsTunnelHopTable              ^                     |              |                     +--> mplsTunnelCHopTable              V                     |   mplsTunnelCRLDPResTable          +--> mplsTunnelARHopTable8.  Tables, Scalars, and Notifications in MPLS-FTN-STD-MIB8.1.  Tables   MPLS-FTN-STD-MIB contains the following tables.   -  The FEC-to-NHLFE Table (mplsFTNTable) defines the FEC to NHLFE      rules to be applied to incoming packets, and the actions to be      taken on matching packets.   -  The FEC-to-NHLFE Mapping Table (mplsFTNMapTable) provides the      capability to activate FTN rules defined in the mplsFTNTable on      specific interfaces in the system.Nadeau, et al.               Informational                     [Page 18]

RFC 4221                MPLS Management Overview           November 2005   -  Performance statistics for FTN rules are found in the      mplsFTNPerfTable.8.2.  Scalars   This MIB module contains the scalars mplsFTNTableLastChanged and   mplsFTNMapTableLastChanged to indicate the last time an object   changed in mplsFTNTable and mplsFTNMapTable, respectively.  Another   scalar, mplsFTNIndexNext, is used to supply the next valid index for   creating new conceptual rows in mplsFTNTable.8.3.  Notifications   There are no notifications in this MIB module.8.4.  Dependencies between MIB Module Tables   The tables in MPLS-FTN-STD-MIB are related as shown on the diagram   below.  The arrows indicate a reference from one table to another.                         mplsFTNTable                              ^                              |                       mplsFTNMapTable                              ^                              |                       mplsFTNPerfTable9.  Tables and Objects in TE-LINK-STD-MIB9.1.  Tables   TE-LINK-STD-MIB contains the following tables.   -  The TE link table (teLinkTable) is used to specify TE links,      including bundled links, and their generic traffic-engineering      parameters.   -  The TE link descriptor table (teLinkDescriptorTable) is used to      list the TE link descriptors.   -  The shared risk link group (SRLG) table (teLinkSrlgTable) is used      to specify the SRLGs associated with TE links.   -  The TE link bandwidth table (teLinkBandwidthTable) is used to      report priority-based bandwidth values associated with TE links.Nadeau, et al.               Informational                     [Page 19]

RFC 4221                MPLS Management Overview           November 2005   -  The component link table (componentLinkTable) is used to identify      the data-bearing component links that are associated with the TE      links and specify the data-bearing link generic traffic      engineering parameters.   -  The component link descriptor table (componentLinkDescriptorTable)      is used to list the data-bearing component link descriptors.   -  The component link bandwidth table (componentLinkBandwidthTable)      is used to report priority-based bandwidth values associated with      data-bearing component links.9.2.  Scalars   There are no scalars in this MIB module.9.3.  Notifications   There are no notifications in this MIB module.9.4.  Dependencies between MIB Module Tables   The tables in TE-LINK-STD-MIB are related as shown on the diagram   below.  The arrows indicate a reference from one table to another.   Note that many of the associations between tables are through a   common index that is the ifIndex of the related interface.                   teLinkTable                            ^                            |   teLinkDescriptorTable ---+                            |   teLinkSrlgTable ---------+                            |   teLinkBandwidthTable ----+                   componentLinkTable                                   ^                                   |   componentLinkDescriptorTable ---+                                   |   componentLinkBandwidthTable ----+Nadeau, et al.               Informational                     [Page 20]

RFC 4221                MPLS Management Overview           November 200510.  Table Dependencies between MPLS MIB ModulesSection 4.11 gave an overview of how the MPLS MIB modules are   related.  Now that the tables in the MIB modules have been   introduced, it is possible to give a more detailed diagram of these   relationships.   MPLS-TC-STD-MIB is left off the diagram because many of the MIB   module tables use textual conventions from that MIB module.             mplsLsrXCTable   mplsLsrInSegmentTable                         ^     ^                         |     |                         +---- mplsLdpLspTable                         |     |   mplsTunnelTable ------+     V      ^                  |    mplsLsrOutSegmentTable      |                  |   mplsFTNTable ---------+11.  A Note on Interfaces   The Interfaces Group of IF-MIB [RFC2863] defines generic managed   objects for managing interfaces.  The MPLS MIB modules make   references to interfaces so that it can be clearly determined where   the procedures managed by the MIB modules should be performed.   Additionally, the MPLS MIB modules (notably MPLS-TE-STD-MIB and TE-   LINK-STD-MIB) utilize interface stacking within the Interface Group.11.1.  MPLS Tunnels as Interfaces   MPLS-TE-STD-MIB builds on the concept of managing MPLS Tunnels as   logical interfaces.  [RFC2863] states that the interfaces table   (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, an MPLS Tunnel managed   as an interface is represented as an entry in the ifTable.  The   interrelation of entries in the ifTable is defined by the Interfaces   Stack Group defined in [RFC2863].   When using MPLS Tunnels as interfaces, the interface stack table   might appear as follows:Nadeau, et al.               Informational                     [Page 21]

RFC 4221                MPLS Management Overview           November 2005   +------------------------------------------------+   | MPLS tunnel interface ifType = mplsTunnel(150) |   +------------------------------------------------+   |        MPLS interface ifType = mpls(166)       |   +------------------------------------------------+   |               Underlying layer                 |   +------------------------------------------------+   In the diagram above, "Underlying layer" refers to the ifIndex of any   interface type for which MPLS internetworking has been defined.   Examples include ATM, Frame Relay, and Ethernet.   A detailed listing of the mapping between ifTable objects and their   use for MPLS Tunnels is given in [TEMIB].  A few key objects are   listed here to provide an overview of the concepts.   Each MPLS tunnel is represented by an entry in the ifTable.  Each   tunnel is therefore assigned a unique ifIndex.   The type of an interface represented by an entry in the ifTable is   indicated by the ifType object.  The value that is allocated to   identify an MPLS tunnel is 150.   The ifOperStatus object reflects the actual operational status of the   MPLS tunnel and may be mapped from the mplsTunnelOperStatus object.   It may be considered convenient and good management to set the ifName   object to reflect the name of the MPLS tunnel as contained in the   mplsTunnelName object.11.2.  Application of the Interfaces Group to TE Links   TE-LINK-STD-MIB also uses interface stacking to manage TE Link   interfaces as logical interfaces.  The TE Link interface is   represented as an entry in the ifTable.  The interrelation of entries   in the ifTable is defined by Interfaces Stack Group defined in   [RFC2863].  When using TE Link interfaces, the interface stack table   might appear as follows:Nadeau, et al.               Informational                     [Page 22]

RFC 4221                MPLS Management Overview           November 2005   +-------------------------------------------------------------------+   | MPLS interface ifType = mpls(166)                                 |   | ifIndex = 1                                                       |   +-------------------------------------------------------------------+   | TE link (bundled link) ifType = teLink(200)                       |   | ifIndex = 2                                                       |   +--------------------------------+-+--------------------------------+   | TE link ifType = teLink(200)   | | TE link ifType = teLink(200)   |   | ifIndex = 3                    | | ifIndex = 4                    |   +--------------------------------+ +--------------------------------+   | Component link                 | | Component link                 |   | ifType = opticalTransport(196) | | ifType = opticalTransport(196) |   | ifIndex = 5                    | | ifIndex = 6                    |   +--------------------------------+ +--------------------------------+   In the above diagram, "opticalTransport" is an example of an   underlying physical interface: in this case an optical transport   interface.  TE link management and bundling can be seen in the levels   of interface stacking.  Two TE links are defined, each managing an   optical transport link.  These two TE links are combined into a   bundle, which is managed as a single TE link interface.  This TE Link   interface supports MPLS and is presented as an MPLS interface.   A detailed listing of the mapping between ifTable objects and their   use for TE Links is given in [TELMIB].  A few key objects are listed   here to provide an overview of the concepts.   Each TE Link interface is represented by a separate entry in the   ifTable, with a unique ifIndex.   The type of an interface represented by an entry in the ifTable is   indicated by the ifType object.  The value that is allocated to   identify a TE Link is 200.11.3.  References to Interface MIB Objects from MPLS MIB Modules   MPLS-TE-STD-MIB contains two objects that reference the management of   an MPLS tunnel as an interface.  mplsTunnelIsIf is a TruthValue that   indicates whether the tunnel is present in the ifTable.  If the   tunnel is managed as an interface, the mplsTunnelIfIndex object   contains the ifIndex that identifies the corresponding entry in the   ifTable.   MPLS-LSR-STD-MIB includes a table (mplsInterfaceTable) for   configuring the support for MPLS on specific interfaces.  A   conceptual row in this table is created automatically by an LSR for   every interface that is capable of and configured for support of   MPLS.  A conceptual row in this table will exist if and only if aNadeau, et al.               Informational                     [Page 23]

RFC 4221                MPLS Management Overview           November 2005   corresponding entry in ifTable exists with ifType = mpls(166).  The   fate of the entries in the two tables are closely linked so that if   the entry in the ifTable is operationally disabled, the entry in   mplsInterfaceTable is deleted.  During the life of an entry in   mplsInterfaceTable, a corresponding entry is managed in   mplsInterfacePerfTable to show performance counters for the MPLS-   capable interface.   The ifIndex that identifies MPLS-capable interfaces also plays an   important indexing role in MPLS-LSR-STD-MIB.  In-segments (that is,   incoming LSP labels) are represented in mplsInSegmentTable, which is   indexed by the mplsInSegmentIfIndex and mplsInSegmentLabel objects.   mplsInSegmentIfIndex is set to the ifIndex of the incoming MPLS-   capable interface.  mplsInSegmentLabel identifies the incoming MPLS   label.  Note that the corresponding mplsOutSegmentTable contains an   mplsOutSegmentIfIndex object to identify the outgoing MPLS-capable   interface, but that this does not form part of the index of the   table.   MPLS-LDP-STD-MIB uses ifIndex extensively to identify the interface   over which MPLS is active.   Within MPLS-FTN-STD-MIB, mplsFTNMapTable maps entries in mplsFTNTable   to interfaces on which mplsFTNTable entries should be activated.   Interfaces are identified using their ifIndex values.12.  Management Options   It is not the intention of this document to provide instructions or   advice to implementers of Management Stations, 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.   All MPLS LSPs may appear in MPLS-LSR-STD-MIB.  At transit nodes, they   are seen as full cross-connects between incoming labels on incoming   interfaces and outgoing labels on outgoing interfaces.  At ingress or   egress points, the cross-connections are unbalanced having spoof   upstream or downstream legs, respectively.   Split and merge points of LSPs may be represented as more complex   cross-connects in MPLS-LSR-STD-MIB.  Similarly, bidirectional LSPs   can be represented by using the same cross-connect index for each of   the forward and reverse cross-connections.   The modules in the LDP MIB are intended solely for use with LDP and   CR-LDP.  LSPs that are signaled through other means may conveniently   be stored in mplsLdpLspTable for consistency with LSPs set up usingNadeau, et al.               Informational                     [Page 24]

RFC 4221                MPLS Management Overview           November 2005   LDP, but there is little further value to this because the table   gives only pointers into MPLS-LSR-STD-MIB.  If, however, the LSPs are   established with associated FECs using some signaling method other   than LDP (for example, BGP), it may be advantageous to use   mplsLdpLspTable, mplsFecTable, and mplsLdpLspFecTable to correlate   the LSPs.   Note that if CR-LDP is the signaling protocol, there is no   requirement to use the LSP-related tables in the LDP MIB since the   LSP will be adequately represented in MPLS-TE-MIB and MPLS-LSR-STD-   MIB.   MPLS tunnels may be represented in MPLS-TE-STD-MIB with their cross-   connects indicated in MPLS-LSR-STD-MIB.  Tunnels are often (although   not always) set up with a series of constraints that may be   represented in MPLS-TE-STD-MIB.  Note that a distinguishing feature   of a tunnel is that it has an ingress and an egress, where LSPs   established through LDP may be end-to-end or may be hop-by-hop.   All LSPs (tunnels and non-tunnels) may be established as a result of   signaling protocols already defined or for future study.  In   addition, LSPs may be set up manually by issuing configuration   commands to each of the LSRs on the LSP.  These commands may utilize   SNMP by performing SET operations to the MIB module tables and   objects described here.  Alternatively, configuration may be through   some non-standard interface such as a Command Line or a Graphical   User Interface.  Such configured LSPs may also be represented in the   MIB module tables.   Do not be misled by considerations of the "permanence" of LSPs when   deciding which tables of which MIB modules to use.  An MPLS tunnel   may have a very long life expectancy if it is set up by an amnesiac   user.  Otherwise, it may have a very short lifetime if it is   automatically provisioned to satisfy on-demand traffic requirements.   Similarly, an LSP established in response to a routing protocol   (sometimes known as a hop-by-hop LSP) may be equally stable or   unstable.13.  Related IETF MIB Modules   This section describes the broad interactions between MIB modules   produced by the PWE3, PPVPN, and CCAMP working groups and the MPLS   MIB modules.  This information is provided as background and is not   central to this document.Nadeau, et al.               Informational                     [Page 25]

RFC 4221                MPLS Management Overview           November 200513.1.  PWE3 Working Group MIB Modules   The PWE3 working group has produced a document [PWE3FW] that includes   a description of the framework for MIB modules within PWE3 operation.   Since the PWE3 architecture includes the use of MPLS as an emulated   service and as a PSN service, the MPLS MIB modules described above   may be leveraged.  The PWE3 framework document describes the   interactions between the MPLS MIB modules and the PWE3 MIB modules.13.2.  PPVPN Working Group MIB Modules   At present, the PPVPN working group has not included a discussion of   how the MPLS MIB modules interact with the MIB modules being produced   by that working group.  The authors of this document hope to make a   forthcoming addition to the PPVPN framework document [PPVPNFW]   detailing these interactions.  At the moment, there are two MIB   modules, [VPNMIB] and [VPNTCMIB], which are discussed next.13.2.1.  PPVPN-MPLS-VPN-STD-MIB   PPVPN-MPLS-VPN-STD-MIB describes managed objects that are used to   model and manage RFC2547bis MPLS VPNs [RFC2547Bis].  This MIB module   contains tables that model virtual routing forwarding entries (VRFs),   as well as the interfaces associated with those VRFs.13.2.1.1.  Position in the OID Tree      transmission --RFC 2578 [RFC2578]        |        +- vpnMIB -- PPVPN-MPLS-VPN-STD-MIB13.2.1.2.  Dependencies   This MIB module currently has no direct dependencies on any of the   MPLS MIB modules.  This MIB module models MPLS VPN interfaces as   entries in the Interfaces MIB's Interfaces Table (ifTable).  This MIB   module may be modified in the future to import textual conventions   from MPLS-TC-STD-MIB.   A specific textual conventions MIB module [VPNTCMIB] defines textual   conventions that are imported into PPVPN-MPLS-VPN-STD-MIB.13.3.  CCAMP Working Group MIB Modules   The CCAMP working group is developing MIB modules in support of GMPLS   that interact directly with the MPLS MIB modules.  Along with any MIB   modules produced by the CCAMP working group, a separate CCAMP-Nadeau, et al.               Informational                     [Page 26]

RFC 4221                MPLS Management Overview           November 2005   specific Management Framework document is expected to be issued   describing the relationship between these MIB modules and the   existing MPLS (and other) MIB modules.14.  Traffic Engineering Working Group TE MIB   The TEWG has produced a traffic engineering MIB (TE-MIB) [TEWGMIB]   containing objects for monitoring traffic-engineered tunnels at their   ingress points.   In many senses TE-MIB contains the same information as MPLS-TE-STD-   MIB.  Both MIB modules can be used to monitor MPLS tunnels; however,   TE-MIB is minimalistic and caters best to TE tunnels as tunnels, at   the expense of not having many advanced features of MPLS-TE-STD-MIB,   whereas MPLS-TE-STD-MIB can deconstruct tunnels into hop-by-hop   cross-connects, at the expense of more complexity.   The TE-MIB module imports textual conventions from the MPLS-TC-STD-   MIB module and therefore is dependent on that document.14.1.  Choosing between TE MIB Modules   TE-MIB is a flexible MIB module designed to manage traffic   engineering tunnels regardless of the implementation technology.   This flexibility and a focus on simplicity lead to some compromises.   - Some MPLS configuration parameters are left out.  For example, the     resource management in TE-MIB is confined to bandwidth, so missing     the full IntServ control.   - Other TE-MIB parameters are present but with only limited options;     for example, the ability to configure different label distribution     methods per LSP.   Extensibility of TE-MIB to related concepts (such as DiffServ and   Fast Reroute) and integrations with other MIB modules (such as that   in MPLS-LSR-STD-MIB) are not work items at the time of writing.  The   MPLS MIB modules are more closely integrated as described in this   document.   Write/create access to TE-MIB is only available at the ingress, where   it can be used to configure an ingress to signal a tunnel with   constraints.  It cannot be used to configure hop-by-hop cross-   connects to build a tunnel.   The purpose of TE-MIB module is to allow a Management Agent to   configure tunnels, and to inspect and monitor all tunnels (however   created) at their ingress points.  It does not provide informationNadeau, et al.               Informational                     [Page 27]

RFC 4221                MPLS Management Overview           November 2005   about tunnels at any other point in the network (that is, at transit   or egress nodes).  This module can be used, for example, to configure   the constraints of a tunnel, whereupon the ingress would compute the   tunnel path and signal it.  The MIB module can then be used at the   ingress to monitor the tunnel's path(s), their status, and the   tunnel's uptime and counters.  This MIB module is not designed to   configure hop-by-hop cross-connects to build a tunnel.15.  Security Considerations   This document describes the interrelationships amongst the different   MIB modules relevant to MPLS management and as such does not have any   security implications in and of itself.   Each specific MIB document specifies specific MIB objects, and such a   document 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 and GET (read) 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,RFC 3414 [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 this MIB is properly   configured to give access to only those objects, and to those   principals (users) that have legitimate rights to access them.16.  Acknowledgements   Many small pieces of text in this document have been borrowed from   the documents that define the MIB modules described here.  The   authors would like to express appreciation to all who worked on those   MIB documents.   Thanks also to all those who attended the November 2002 MPLS MIB open   meeting and gave constructive feedback, and in particular to Sharon   Chisholm for her thoughts on Management Options.   Thanks to Kireeti Kompella for revising the text on TE-MIB.Nadeau, et al.               Informational                     [Page 28]

RFC 4221                MPLS Management Overview           November 2005   Without the consistent pressure and encouragement from Bert Wijnen,   this document would not have been written.17.  Normative References   [FTNMIB]      Nadeau, T., Srinivasan, C., and A. Viswanathan,                 "Multiprotocol Label Switching (MPLS) Forwarding                 Equivalence Class To Next Hop Label Forwarding Entry                 (FEC-To-NHLFE) Management Information Base (MIB)",RFC3814, June 2004.   [LDPMIB]      Cucchiara, J., Sjostrand, H., and J. Luciani,                 "Definitions of Managed Objects for the Multiprotocol                 Label Switching (MPLS), Label Distribution Protocol                 (LDP)",RFC 3815, June 2004.   [LSRMIB]      Srinivasan, C., Viswanathan, A., and T. Nadeau,                 "Multiprotocol Label Switching (MPLS) Label Switching                 Router (LSR) Management Information Base (MIB)",RFC3813, June 2004.   [RFC2863]     McCloghrie, K. and F. Kastenholtz, "The Interfaces                 Group MIB ",RFC 2863, June 2000.   [RFC3289]     Baker, F., Chan, K., and A. Smith, "Management                 Information Base for the Differentiated Services                 Architecture",RFC 3289, May 2002.   [TCMIB]       Nadeau, T. and J. Cucchiara, "Definitions of Textual                 Conventions (TCs) for Multiprotocol Label Switching                 (MPLS) Management",RFC 3811, June 2004.   [TELMIB]      Dubuc, M., Dharanikota, S., Nadeau, T., J. Lang,                 "Traffic Engineering Link Management Information Base",RFC 4220, November 2005.   [TEMIB]       Srinivasan, C., Viswanathan, A., and T. Nadeau,                 "Multiprotocol Label Switching (MPLS) Traffic                 Engineering (TE) Management Information Base (MIB)",RFC 3812, June 2004.Nadeau, et al.               Informational                     [Page 29]

RFC 4221                MPLS Management Overview           November 200518.  Informative References   [PPVPNFW]     Callon, R. and M. Suzuki, "A Framework for Layer 3                 Provider-Provisioned Virtual Private Networks                 (PPVPNs)",RFC 4110, July 2005.   [PWE3FW]      Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-                 to-Edge (PWE3) Architecture",RFC 3985, March 2005.   [RFC2026]     Bradner, S., "The Internet Standards Process --                 Revision 3",BCP 9,RFC 2026, October 1996.   [RFC2547Bis]  Rosen, E., et al.,"MPLS/BGP VPNs", Work in Progress,                 October 2002.   [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,                 January 2001.   [RFC3036]     Andersson, L., Doolan, P., Feldman, N., Fredette, A.,                 and B. Thomas, "LDP Specification",RFC 3036, January                 2001.   [RFC3410]     Case, J., Mundy, R., Partain, D. and B. Stewart,                 "Introduction and Applicability Statements for                 Internet-Standard Management Framework",RFC 3410,                 December 2002.   [RFC3413]     Levi, D., Meyer, P., and B. Stewart, "Simple Network                 Management Protocol (SNMP) Applications", STD 62,RFC3413, 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.Nadeau, et al.               Informational                     [Page 30]

RFC 4221                MPLS Management Overview           November 2005   [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.   [TEWGMIB]     Kompella, K., "A Traffic Engineering (TE) MIB",RFC3970, January 2005.   [VPNMIB]      Nadeau, T., et al., "MPLS/BGP Virtual Private Network                 Management Information Base Using SMIv2", Work in                 Progress, November 2002.   [VPNTCMIB]    Schliesser, B. and T. Nadeau, "Definition of Textual                 Conventions for Provider Provisioned Virtual Private                 Network (PPVPN) Management", Work in Progress, November                 2002.Authors' Addresses   Thomas D. Nadeau   Cisco Systems, Inc.   1414 Massachusetts Ave.   Boxborough, MA 01719   EMail: tnadeau@cisco.com   Cheenu Srinivasan   Bloomberg L.P.   731 Lexington Avenue   New York, NY 10022   Phone: (212) 617-3682   EMail: cheenu@bloomberg.net   Adrian Farrel   Old Dog Consulting   Phone: +44 (0) 1978 860944   EMail: adrian@olddog.co.ukNadeau, et al.               Informational                     [Page 31]

RFC 4221                MPLS Management Overview           November 2005Full Copyright Statement   Copyright (C) The Internet Society (2005).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and except as set forth therein, the authors   retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the procedures with respect to rights in RFC documents can be   found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at ietf-   ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Nadeau, et al.               Informational                     [Page 32]

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