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Internet Engineering Task Force (IETF)                            K. LamRequest for Comments: 5951                                Alcatel-LucentCategory: Standards Track                                   S. MansfieldISSN: 2070-1721                                                  E. Gray                                                                Ericsson                                                          September 2010Network Management Requirements for MPLS-based Transport NetworksAbstract   This document specifies the requirements for the management of   equipment used in networks supporting an MPLS Transport Profile   (MPLS-TP).  The requirements are defined for specification of   network management aspects of protocol mechanisms and procedures   that constitute the building blocks out of which the MPLS   Transport Profile is constructed.  That is, these requirements   indicate what management capabilities need to be available in   MPLS for use in managing the MPLS-TP.  This document is intended   to identify essential network management capabilities, not to   specify what functions any particular MPLS implementation   supports.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by   the Internet Engineering Steering Group (IESG).  Further   information on Internet Standards is available inSection 2 of   RFC 5741.   Information about the current status of this document, any   errata, and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc5951.Lam, et al.                  Standards Track                    [Page 1]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010Copyright Notice   Copyright (c) 2010 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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.Lam, et al.                  Standards Track                    [Page 2]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010Table of Contents1. Introduction ....................................................41.1. Terminology ................................................52. Management Interface Requirements ...............................73. Management Communication Channel (MCC) Requirements .............74. Management Communication Network (MCN) Requirements .............75. Fault Management Requirements ...................................95.1. Supervision Function .......................................95.2. Validation Function .......................................105.3. Alarm Handling Function ...................................115.3.1. Alarm Severity Assignment ..........................115.3.2. Alarm Suppression ..................................115.3.3. Alarm Reporting ....................................115.3.4. Alarm Reporting Control ............................126. Configuration Management Requirements ..........................126.1. System Configuration ......................................126.2. Control Plane Configuration ...............................136.3. Path Configuration ........................................136.4. Protection Configuration ..................................146.5. OAM Configuration .........................................147. Performance Management Requirements ............................157.1. Path Characterization Performance Metrics .................157.2. Performance Measurement Instrumentation ...................167.2.1. Measurement Frequency ..............................167.2.2. Measurement Scope ..................................178. Security Management Requirements ...............................178.1. Management Communication Channel Security .................178.2. Signaling Communication Channel Security ..................188.3. Distributed Denial of Service .............................189. Security Considerations ........................................1910. Acknowledgments ...............................................1911. References ....................................................1911.1. Normative References .....................................1912.2. Informative References ...................................20Appendix A.  Communication Channel (CCh) Examples..................22   Contributor's Address .............................................24Lam, et al.                  Standards Track                    [Page 3]

RFC 5951        NM Requirements for MPLS-based Transport  September 20101.  Introduction   This document specifies the requirements for the management of   equipment used in networks supporting an MPLS Transport Profile   (MPLS-TP).  The requirements are defined for specification of network   management aspects of protocol mechanisms and procedures that   constitute the building blocks out of which the MPLS Transport   Profile is constructed.  That is, these requirements indicate what   management capabilities need to be available in MPLS for use in   managing the MPLS-TP.  This document is intended to identify   essential network management capabilities, not to specify what   functions any particular MPLS implementation supports.   This document also leverages management requirements specified in   ITU-T G.7710/Y.1701 [1] andRFC 4377 [2], and attempts to comply with   the guidelines defined inRFC 5706 [15].   ITU-T G.7710/Y.1701 defines generic management requirements for   transport networks.RFC 4377 specifies the operations and management   requirements, including operations-and-management-related network   management requirements, for MPLS networks.   This document is a product of a joint ITU-T and IETF effort to   include an MPLS Transport Profile (MPLS-TP) within the IETF MPLS and   Pseudowire Emulation Edge-to-Edge (PWE3) architectures to support   capabilities and functionality of a transport network as defined by   the ITU-T.   The requirements in this document derive from two sources:   1) MPLS and PWE3 architectures as defined by the IETF, and   2) packet transport networks as defined by the ITU-T.   Requirements for management of equipment in MPLS-TP networks are   defined herein.  Related functions of MPLS and PWE3 are defined   elsewhere (and are out of scope in this document).   This document expands on the requirements in ITU-T G.7710/Y.1701 [1]   andRFC 4377 [2] to cover fault, configuration, performance, and   security management for MPLS-TP networks, and the requirements for   object and information models needed to manage MPLS-TP networks and   network elements.   In writing this document, the authors assume the reader is familiar   with RFCs 5921 [8] and 5950 [9].Lam, et al.                  Standards Track                    [Page 4]

RFC 5951        NM Requirements for MPLS-based Transport  September 20101.1.  Terminology   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described inRFC 2119 [5].   Although this document is not a protocol specification, the use of   this language clarifies the instructions to protocol designers   producing solutions that satisfy the requirements set out in this   document.   Anomaly: The smallest discrepancy that can be observed between actual   and desired characteristics of an item.  The occurrence of a single   anomaly does not constitute an interruption in ability to perform a   required function.  Anomalies are used as the input for the   Performance Monitoring (PM) process and for detection of defects   (from [21], Section 3.7).   Communication Channel (CCh): A logical channel between network   elements (NEs) that can be used (for example) for management or   control plane applications.  The physical channel supporting the CCh   is technology specific.  SeeAppendix A.   Data Communication Network (DCN): A network that supports Layer 1   (physical layer), Layer 2 (data-link layer), and Layer 3 (network   layer) functionality for distributed management communications   related to the management plane, for distributed signaling   communications related to the control plane, and other operations   communications (e.g., order-wire/voice communications, software   downloads, etc.).   Defect: The density of anomalies has reached a level where the   ability to perform a required function has been interrupted.  Defects   are used as input for performance monitoring, the control of   consequent actions, and the determination of fault cause (from [21],   Section 3.24).   Failure: The fault cause persisted long enough to consider the   ability of an item to perform a required function to be terminated.   The item may be considered as failed; a fault has now been detected   (from [21], Section 3.25).   Fault: A fault is the inability of a function to perform a required   action.  This does not include an inability due to preventive   maintenance, lack of external resources, or planned actions (from   [21], Section 3.26).Lam, et al.                  Standards Track                    [Page 5]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   Fault Cause: A single disturbance or fault may lead to the detection   of multiple defects.  A fault cause is the result of a correlation   process that is intended to identify the defect that is   representative of the disturbance or fault that is causing the   problem (from [21], Section 3.27).   Fault Cause Indication (FCI): An indication of a fault cause.   Management Communication Channel (MCC): A CCh dedicated for   management plane communications.   Management Communication Network (MCN): A DCN supporting management   plane communication is referred to as a Management Communication   Network (MCN).   MPLS-TP NE: A network element (NE) that supports the functions of   MPLS necessary to participate in an MPLS-TP based transport service.   SeeRFC 5645 [7] for further information on functionality required to   support MPLS-TP.   MPLS-TP network: a network in which MPLS-TP NEs are deployed.   Operations, Administration and Maintenance (OAM), On-Demand and   Proactive: One feature of OAM that is largely a management issue is   control of OAM; on-demand and proactive are modes of OAM mechanism   operation defined in (for example) Y.1731 ([22] - Sections3.45 and   3.44, respectively) as:   o  On-demand OAM - OAM actions that are initiated via manual      intervention for a limited time to carry out diagnostics.      On-demand OAM can result in singular or periodic OAM actions      during the diagnostic time interval.   o  Proactive OAM - OAM actions that are carried on continuously to      permit timely reporting of fault and/or performance status.   (Note that it is possible for specific OAM mechanisms to only have a   sensible use in either on-demand or proactive mode.)   Operations System (OS): A system that performs the functions that   support processing of information related to operations,   administration, maintenance, and provisioning (OAM&P) for the   networks, including surveillance and testing functions to support   customer access maintenance.Lam, et al.                  Standards Track                    [Page 6]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   Signaling Communication Channel (SCC): A CCh dedicated for control   plane communications.  The SCC can be used for GMPLS/ASON signaling   and/or other control plane messages (e.g., routing messages).   Signaling Communication Network (SCN): A DCN supporting control plane   communication is referred to as a Signaling Communication Network   (SCN).2.  Management Interface Requirements   This document does not specify a preferred management interface   protocol to be used as the standard protocol for managing MPLS-TP   networks.  Managing an end-to-end connection across multiple operator   domains where one domain is managed (for example) via NETCONF [16] or   SNMP [17], and another domain via CORBA [18], is allowed.   1) For the management interface to the management system, an MPLS-TP      NE MAY actively support more than one management protocol in any      given deployment.   For example, an operator can use one protocol for configuration of an   MPLS-TP NE and another for monitoring.  The protocols to be supported   are at the discretion of the operator.3.  Management Communication Channel (MCC) Requirements   1) Specifications SHOULD define support for management connectivity      with remote MPLS-TP domains and NEs, as well as with termination      points located in NEs under the control of a third party network      operator.  See ITU-T G.8601 [23] for example scenarios in multi-      carrier, multi-transport technology environments.   2) For management purposes, every MPLS-TP NE MUST connect to an OS.      The connection MAY be direct (e.g., via a software, hardware, or      proprietary protocol connection) or indirect (via another MPLS-TP      NE).  In this document, any management connection that is not via      another MPLS-TP NE is a direct management connection.  When an      MPLS-TP NE is connected indirectly to an OS, an MCC MUST be      supported between that MPLS-TP NE and any MPLS-TP NE(s) used to      provide the connection to an OS.4.  Management Communication Network (MCN) Requirements   Entities of the MPLS-TP management plane communicate via a DCN, or   more specifically via the MCN.  The MCN connects management systems   with management systems, management systems with MPLS-TP NEs, and (in   the indirect connectivity case discussed insection 3) MPLS-TP NEs   with MPLS-TP NEs.Lam, et al.                  Standards Track                    [Page 7]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010RFC 5586 [14] defines a Generic Associated Channel (G-ACh) to enable   the realization of a communication channel (CCh) between adjacent   MPLS-TP NEs for management and control.RFC 5718 [10] describes how   the G-ACh can be used to provide infrastructure that forms part of   the MCN and SCN.  It also explains how MCN and SCN messages are   encapsulated, carried on the G-ACh, and decapsulated for delivery to   management or signaling/routing control plane components on a label   switching router (LSR).Section 7 of ITU-T G.7712/Y.1703 [6] describes the transport DCN   architecture and requirements as follows:   1) The MPLS-TP MCN MUST support the requirements for:      a) CCh access functions specified inSection 7.1.1;      b) MPLS-TP SCC data-link layer termination functions specified inSection 7.1.2.3;      c) MPLS-TP MCC data-link layer termination functions specified inSection 7.1.2.4;      d) Network layer PDU into CCh data-link frame encapsulation         functions specified inSection 7.1.3;      e) Network layer PDU forwarding (Section 7.1.6), interworking         (Section 7.1.7), and encapsulation (Section 7.1.8) functions,         as well as tunneling (Section 7.1.9) and routing (Section7.1.10) functions.   As a practical matter, MCN connections will typically have addresses.   See the section on Identifiers inRFC 5921 [8] for further   information.   In order to have the MCN operate properly, a number of management   functions for the MCN are needed, including:   o  Retrieval of DCN network parameters to ensure compatible      functioning, e.g., packet size, timeouts, quality of service,      window size, etc.;   o  Establishment of message routing between DCN nodes;   o  Management of DCN network addresses;   o  Retrieval of operational status of the DCN at a given node;Lam, et al.                  Standards Track                    [Page 8]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   o  Capability to enable/disable access by an NE to the DCN.  Note      that this is to allow the isolation of a malfunctioning NE to keep      it from impacting the rest of the network.5.  Fault Management Requirements   The Fault Management functions within an MPLS-TP NE enable the   supervision, detection, validation, isolation, correction, and   reporting of abnormal operation of the MPLS-TP network and its   environment.5.1.  Supervision Function   The supervision function analyzes the actual occurrence of a   disturbance or fault for the purpose of providing an appropriate   indication of performance and/or detected fault condition to   maintenance personnel and operations systems.   1) The MPLS-TP NE MUST support supervision of the OAM mechanisms that      are deployed for supporting the OAM requirements defined inRFC5860 [3].   2) The MPLS-TP NE MUST support the following data-plane forwarding      path supervision functions:      a) Supervision of loop-checking functions used to detect loops in         the data-plane forwarding path (which result in non-delivery of         traffic, wasting of forwarding resources, and unintended self-         replication of traffic);      b) Supervision of failure detection;   3) The MPLS-TP NE MUST support the capability to configure data-plane      forwarding path related supervision mechanisms to perform      on-demand or proactively.   4) The MPLS-TP NE MUST support supervision for software processing --      e.g., processing faults, storage capacity, version mismatch,      corrupted data, and out of memory problems, etc.   5) The MPLS-TP NE MUST support hardware-related supervision for      interchangeable and non-interchangeable unit, cable, and power      problems.   6) The MPLS-TP NE SHOULD support environment-related supervision for      temperature, humidity, etc.Lam, et al.                  Standards Track                    [Page 9]

RFC 5951        NM Requirements for MPLS-based Transport  September 20105.2.  Validation Function   Validation is the process of integrating Fault Cause indications into   Failures.  A Fault Cause Indication (FCI) indicates a limited   interruption of the required transport function.  A Fault Cause is   not reported to maintenance personnel because it might exist only for   a very short period of time.  Note that some of these events are   summed up in the Performance Monitoring process (seeSection 7), and   when this sum exceeds a configured value, a threshold crossing alert   (report) can be generated.   When the Fault Cause lasts long enough, an inability to perform the   required transport function arises.  This failure condition is   subject to reporting to maintenance personnel and/or an OS because   corrective action might be required.  Conversely, when the Fault   Cause ceases after a certain time, clearing of the Failure condition   is also subject to reporting.   1) The MPLS-TP NE MUST perform persistency checks on fault causes      before it declares a fault cause a failure.   2) The MPLS-TP NE SHOULD provide a configuration capability for      control parameters associated with performing the persistency      checks described above.   3) An MPLS-TP NE MAY provide configuration parameters to control      reporting and clearing of failure conditions.   4) A data-plane forwarding path failure MUST be declared if the fault      cause persists continuously for a configurable time (Time-D).  The      failure MUST be cleared if the fault cause is absent continuously      for a configurable time (Time-C).   Note: As an example, the default time values might be as follows:      Time-D = 2.5 +/- 0.5 seconds      Time-C = 10 +/- 0.5 seconds   These time values are as defined in G.7710 [1].   5) MIBs - or other object management semantics specifications -      defined to enable configuration of these timers SHOULD explicitly      provide default values and MAY provide guidelines on ranges and      value determination methods for scenarios where the default value      chosen might be inadequate.  In addition, such specifications      SHOULD define the level of granularity at which tables of these      values are to be defined.Lam, et al.                  Standards Track                   [Page 10]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   6) Implementations MUST provide the ability to configure the      preceding set of timers and SHOULD provide default values to      enable rapid configuration.  Suitable default values, timer      ranges, and level of granularity are out of scope in this document      and form part of the specification of fault management details.      Timers SHOULD be configurable per NE for broad categories (for      example, defects and/or fault causes), and MAY be configurable      per-interface on an NE and/or per individual defect/fault cause.   7) The failure declaration and clearing MUST be time stamped.  The      time-stamp MUST indicate the time at which the fault cause is      activated at the input of the fault cause persistency (i.e.,      defect-to-failure integration) function, and the time at which the      fault cause is deactivated at the input of the fault cause      persistency function.5.3.  Alarm Handling Function5.3.1.  Alarm Severity Assignment   Failures can be categorized to indicate the severity or urgency of   the fault.   1) An MPLS-TP NE SHOULD support the ability to assign severity (e.g.,      Critical, Major, Minor, Warning) to alarm conditions via      configuration.   See G.7710 [1], Section 7.2.2 for more detail on alarm severity   assignment.  For additional discussion of Alarm Severity management,   see discussion of alarm severity inRFC 3877 [11].5.3.2.  Alarm Suppression   Alarms can be generated from many sources, including OAM, device   status, etc.   1) An MPLS-TP NE MUST support suppression of alarms based on      configuration.5.3.3.  Alarm Reporting   Alarm Reporting is concerned with the reporting of relevant events   and conditions, which occur in the network (including the NE,   incoming signal, and external environment).   Local reporting is concerned with automatic alarming by means of   audible and visual indicators near the failed equipment.Lam, et al.                  Standards Track                   [Page 11]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   1) An MPLS-TP NE MUST support local reporting of alarms.   2) The MPLS-TP NE MUST support reporting of alarms to an OS.  These      reports are either autonomous reports (notifications) or reports      on request by maintenance personnel.  The MPLS-TP NE SHOULD report      local (environmental) alarms to a network management system.   3) An MPLS-TP NE supporting one or more other networking technologies      (e.g., Ethernet, SDH/SONET, MPLS) over MPLS-TP MUST be capable of      translating MPLS-TP defects into failure conditions that are      meaningful to the client layer, as described inRFC 4377 [2],      Section 4.7.5.3.4.  Alarm Reporting Control   Alarm Reporting Control (ARC) supports an automatic in-service   provisioning capability.  Alarm reporting can be turned off on a per-   managed entity basis (e.g., LSP) to allow sufficient time for   customer service testing and other maintenance activities in an   "alarm free" state.  Once a managed entity is ready, alarm reporting   is automatically turned on.   1) An MPLS-TP NE SHOULD support the Alarm Reporting Control function      for controlling the reporting of alarm conditions.   See G.7710 [1] (Section 7.1.3.2) andRFC 3878 [24] for more   information about ARC.6.  Configuration Management Requirements   Configuration Management provides functions to identify, collect data   from, provide data to, and control NEs.  Specific configuration tasks   requiring network management support include hardware and software   configuration, configuration of NEs to support transport paths   (including required working and protection paths), and configuration   of required path integrity/connectivity and performance monitoring   (i.e., OAM).6.1.  System Configuration   1) The MPLS-TP NE MUST support the configuration requirements      specified in G.7710 [1], Section 8.1 for hardware.   2) The MPLS-TP NE MUST support the configuration requirements      specified in G.7710 [1], Section 8.2 for software.Lam, et al.                  Standards Track                   [Page 12]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   3) The MPLS-TP NE MUST support the configuration requirements      specified in G.7710 [1], Section 8.13.2.1 for local real-time      clock functions.   4) The MPLS-TP NE MUST support the configuration requirements      specified in G.7710 [1], Section 8.13.2.2 for local real-time      clock alignment with external time reference.   5) The MPLS-TP NE MUST support the configuration requirements      specified in G.7710 [1], Section 8.13.2.3 for performance      monitoring of the clock function.6.2.  Control Plane Configuration   1) If a control plane is supported in an implementation of MPLS-TP,      the MPLS-TP NE MUST support the configuration of MPLS-TP control      plane functions by the management plane.  Further detailed      requirements will be provided along with progress in defining the      MPLS-TP control plane in appropriate specifications.6.3.  Path Configuration   1) In addition to the requirement to support static provisioning of      transport paths (defined inRFC 5645 [7], Section 2.1 -- General      Requirements, requirement 18), an MPLS-TP NE MUST support the      configuration of required path performance characteristic      thresholds (e.g., Loss Measurement <LM>, Delay Measurement <DM>      thresholds) necessary to support performance monitoring of the      MPLS-TP service(s).   2) In order to accomplish this, an MPLS-TP NE MUST support      configuration of LSP information (such as an LSP identifier of      some kind) and/or any other information needed to retrieve LSP      status information, performance attributes, etc.   3) If a control plane is supported, and that control plane includes      support for control-plane/management-plane hand-off for LSP      setup/maintenance, the MPLS-TP NE MUST support management of the      hand-off of Path control.  For example, see RFCs 5943 [19] and      5852 [20].   4) Further detailed requirements SHALL be provided along with      progress in defining the MPLS-TP control plane in appropriate      specifications.Lam, et al.                  Standards Track                   [Page 13]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   5) If MPLS-TP transport paths cannot be statically provisioned using      MPLS LSP and pseudowire management tools (either already defined      in standards or under development), further management      specifications MUST be provided as needed.6.4.  Protection Configuration   1) The MPLS-TP NE MUST support configuration of required path      protection information as follows:      o  designate specifically identified LSPs as working or protecting         LSPs;      o  define associations of working and protecting paths;      o  operate/release manual protection switching;      o  operate/release force protection switching;      o  operate/release protection lockout;      o  set/retrieve Automatic Protection Switching (APS) parameters,         including         o  Wait to Restore time,         o  Protection Switching threshold information.6.5.  OAM Configuration   1) The MPLS-TP NE MUST support configuration of the OAM entities and      functions specified inRFC 5860 [3].   2) The MPLS-TP NE MUST support the capability to choose which OAM      functions are enabled.   3) For enabled OAM functions, the MPLS-TP NE MUST support the ability      to associate OAM functions with specific maintenance entities.   4) The MPLS-TP NE MUST support the capability to configure the OAM      entities/functions as part of LSP setup and tear-down, including      co-routed bidirectional point-to-point, associated bidirectional      point-to-point, and uni-directional (both point-to-point and      point-to-multipoint) connections.   5) The MPLS-TP NE MUST support the configuration of maintenance      entity identifiers (e.g., MEP ID and MIP ID) for the purpose of      LSP connectivity checking.Lam, et al.                  Standards Track                   [Page 14]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   6) The MPLS-TP NE MUST support configuration of OAM parameters to      meet their specific operational requirements, such as      a) one-time on-demand immediately or      b) one-time on-demand pre-scheduled or      c) on-demand periodically based on a specified schedule or      d) proactive on-going.   7) The MPLS-TP NE MUST support the enabling/disabling of the      connectivity check processing.  The connectivity check process of      the MPLS-TP NE MUST support provisioning of the identifiers to be      transmitted and the expected identifiers.7.  Performance Management Requirements   Performance Management provides functions for the purpose of   maintenance, bring-into-service, quality of service, and statistics   gathering.   This information could be used, for example, to compare behavior of   the equipment, MPLS-TP NE, or network at different moments in time to   evaluate changes in network performance.   ITU-T Recommendation G.7710 [1] provides transport performance   monitoring requirements for packet-switched and circuit-switched   transport networks with the objective of providing a coherent and   consistent interpretation of the network behavior in a multi-   technology environment.  The performance management requirements   specified in this document are driven by such an objective.7.1.  Path Characterization Performance Metrics   1) It MUST be possible to determine when an MPLS-TP-based transport      service is available and when it is unavailable.   From a performance perspective, a service is unavailable if there is   an indication that performance has degraded to the extent that a   configurable performance threshold has been crossed and the   degradation persists long enough (i.e., the indication persists for   some amount of time, which is either configurable or well-known) to   be certain it is not a measurement anomaly.   Methods, mechanisms, and algorithms for exactly how unavailability is   to be determined -- based on collection of raw performance data --   are out of scope for this document.Lam, et al.                  Standards Track                   [Page 15]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   2) The MPLS-TP NE MUST support collection and reporting of raw      performance data that MAY be used in determining the      unavailability of a transport service.   3) MPLS-TP MUST support the determination of the unavailability of      the transport service.  The result of this determination MUST be      available via the MPLS-TP NE (at service termination points), and      determination of unavailability MAY be supported by the MPLS-TP NE      directly.  To support this requirement, the MPLS-TP NE management      information model MUST include objects corresponding to the      availability-state of services.   Transport network unavailability is based on Severely Errored Seconds   (SES) and Unavailable Seconds (UAS).  The ITU-T is establishing   definitions of unavailability that are generically applicable to   packet transport technologies, including MPLS-TP, based on SES and   UAS.  Note that SES and UAS are already defined for Ethernet   transport networks in ITU-T Recommendation Y.1563 [25].   4) The MPLS-TP NE MUST support collection of loss measurement (LM)      statistics.   5) The MPLS-TP NE MUST support collection of delay measurement (DM)      statistics.   6) The MPLS-TP NE MUST support reporting of performance degradation      via fault management for corrective actions.   "Reporting" in this context could mean:      o  reporting to an autonomous protection component to trigger         protection switching,      o  reporting via a craft interface to allow replacement of a         faulty component (or similar manual intervention),      o  etc.   7) The MPLS-TP NE MUST support reporting of performance statistics on      request from a management system.7.2.  Performance Measurement Instrumentation7.2.1.  Measurement Frequency   1) For performance measurement mechanisms that support both proactive      and on-demand modes, the MPLS-TP NE MUST support the capability to      be configured to operate on-demand or proactively.Lam, et al.                  Standards Track                   [Page 16]

RFC 5951        NM Requirements for MPLS-based Transport  September 20107.2.2.  Measurement Scope   On measurement of packet loss and loss ratio:   1) For bidirectional (both co-routed and associated) point-to-point      (P2P) connections      a) on-demand measurement of single-ended packet loss and loss         ratio measurement is REQUIRED;      b) proactive measurement of packet loss and loss ratio measurement         for each direction is REQUIRED.   2) For unidirectional (P2P and point-to-multipoint (P2MP))      connection, proactive measurement of packet loss and loss ratio is      REQUIRED.   On Delay measurement:   3) For a unidirectional (P2P and P2MP) connection, on-demand      measurement of delay measurement is REQUIRED.   4) For a co-routed bidirectional (P2P) connection, on-demand      measurement of one-way and two-way delay is REQUIRED.   5) For an associated bidirectional (P2P) connection, on-demand      measurement of one-way delay is REQUIRED.8.  Security Management Requirements   1) The MPLS-TP NE MUST support secure management and control planes.8.1.  Management Communication Channel Security   1) Secure communication channels MUST be supported for all network      traffic and protocols used to support management functions.  This      MUST include, at least, protocols used for configuration,      monitoring, configuration backup, logging, time synchronization,      authentication, and routing.   2) The MCC MUST support application protocols that provide      confidentiality and data-integrity protection.   3) The MPLS-TP NE MUST support the following:      a) Use of open cryptographic algorithms (seeRFC 3871 [4]).Lam, et al.                  Standards Track                   [Page 17]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010      b) Authentication - allow management connectivity only from         authenticated entities.      c) Authorization - allow management activity originated by an         authorized entity, using (for example) an Access Control List         (ACL).      d) Port Access Control - allow management activity received on an         authorized (management) port.8.2.  Signaling Communication Channel Security   Security requirements for the SCC are driven by considerations   similar to MCC requirements described inSection 8.1.   Security Requirements for the control plane are out of scope for this   document and are expected to be defined in the appropriate control   plane specifications.   1) Management of control plane security MUST be defined in the      appropriate control plane specifications.8.3.  Distributed Denial of Service   A denial-of-service (DoS) attack is an attack that tries to prevent a   target from performing an assigned task, or providing its intended   service(s), through any means.  A Distributed DoS (DDoS) can multiply   attack severity (possibly by an arbitrary amount) by using multiple   (potentially compromised) systems to act as topologically (and   potentially geographically) distributed attack sources.  It is   possible to lessen the impact and potential for DoS and DDoS by using   secure protocols, turning off unnecessary processes, logging and   monitoring, and ingress filtering.RFC 4732 [26] provides background   on DoS in the context of the Internet.   1) An MPLS-TP NE MUST support secure management protocols and SHOULD      do so in a manner that reduces potential impact of a DoS attack.   2) An MPLS-TP NE SHOULD support additional mechanisms that mitigate a      DoS (or DDoS) attack against the management component while      allowing the NE to continue to meet its primary functions.Lam, et al.                  Standards Track                   [Page 18]

RFC 5951        NM Requirements for MPLS-based Transport  September 20109.  Security ConsiderationsSection 8 includes a set of security requirements that apply to MPLS-   TP network management.   1) Solutions MUST provide mechanisms to prevent unauthorized and/or      unauthenticated access to management capabilities and private      information by network elements, systems, or users.   Performance of diagnostic functions and path characterization   involves extracting a significant amount of information about network   construction that the network operator might consider private.10.  Acknowledgments   The authors/editors gratefully acknowledge the thoughtful review,   comments, and explanations provided by Adrian Farrel, Alexander   Vainshtein, Andrea Maria Mazzini, Ben Niven-Jenkins, Bernd Zeuner,   Dan Romascanu, Daniele Ceccarelli, Diego Caviglia, Dieter Beller, He   Jia, Leo Xiao, Maarten Vissers, Neil Harrison, Rolf Winter, Yoav   Cohen, and Yu Liang.11.  References11.1.  Normative References   [1]   ITU-T Recommendation G.7710/Y.1701, "Common equipment         management function requirements", July, 2007.   [2]   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,         February 2006.   [3]   Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,         "Requirements for Operations, Administration, and Maintenance         (OAM) in MPLS Transport Networks",RFC 5860, May 2010.   [4]   Jones, G., Ed., "Operational Security Requirements for Large         Internet Service Provider (ISP) IP Network Infrastructure",RFC3871, September 2004.   [5]   Bradner, S., "Key words for use in RFCs to Indicate Requirement         Levels",BCP 14,RFC 2119, March 1997.   [6]   ITU-T Recommendation G.7712/Y.1703, "Architecture and         specification of data communication network", June 2008.Lam, et al.                  Standards Track                   [Page 19]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   [7]   Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,         Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport         Profile",RFC 5654, September 2009.   [8]   Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau, L.,         and L. Berger, "A Framework for MPLS in Transport Networks",RFC 5921, July 2010.   [9]   Mansfield, S. Ed., Gray, E., Ed., and K. Lam, Ed., "Network         Management Framework for MPLS-based Transport Networks",RFC5950, September 2010.12.2.  Informative References   [10]  Beller, D. and A. Farrel, "An In-Band Data Communication         Network For the MPLS Transport Profile",RFC 5718, January         2010.   [11]  Chisholm, S. and D. Romascanu, "Alarm Management Information         Base (MIB)",RFC 3877, September 2004.   [12]  ITU-T Recommendation M.20, "Maintenance philosophy for         telecommunication networks", October 1992.   [13]  Telcordia, "Network Maintenance: Network Element and Transport         Surveillance Messages" (GR-833-CORE), Issue 5, August 2004.   [14]  Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., "MPLS         Generic Associated Channel",RFC 5586, June 2009.   [15]  Harrington, D., "Guidelines for Considering Operations and         Management of New Protocols and Protocol Extensions",RFC 5706,         November 2009.   [16]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and         A. Bierman, Ed., "Network Configuration Protocol (NETCONF)",         Work in Progress, July 2010.   [17]  Presuhn, R., Ed., "Version 2 of the Protocol Operations for the         Simple Network Management Protocol (SNMP)", STD 62,RFC 3416,         December 2002.   [18]  OMG Document formal/04-03-12, "The Common Object Request         Broker: Architecture and Specification", Revision 3.0.3.  March         12, 2004.Lam, et al.                  Standards Track                   [Page 20]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   [19]  Caviglia, D., Bramanti, D., Li, D., and D. McDysan,         "Requirements for the Conversion between Permanent Connections         and Switched Connections in a Generalized Multiprotocol Label         Switching (GMPLS) Network",RFC 5493, April 2009.   [20]  Caviglia, D., Ceccarelli, D., Bramanti, D., Li, D., and S.         Bardalai, "RSVP-TE Signaling Extension for LSP Handover from         the Management Plane to the Control Plane in a GMPLS-Enabled         Transport Network",RFC 5852, April 2010.   [21]  ITU-T Recommendation G.806, "Characteristics of transport         equipment - Description methodology and generic functionality",         January, 2009.   [22]  ITU-T Recommendation Y.1731, "OAM functions and mechanisms for         Ethernet based networks", February, 2008.   [23]  ITU-T Recommendation G.8601, "Architecture of service         management in multi bearer, multi carrier environment", June         2006.   [24]  Lam, H., Huynh, A., and D. Perkins, "Alarm Reporting Control         Management Information Base (MIB)",RFC 3878, September 2004.   [25]  ITU-T Recommendation Y.1563, "Ethernet frame transfer and         availability performance", January 2009.   [26]  Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet Denial-         of-Service Considerations",RFC 4732, December 2006.Lam, et al.                  Standards Track                   [Page 21]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010Appendix A.  Communication Channel (CCh) Examples   A CCh can be realized in a number of ways.   1. The CCh can be provided by a link in a physically distinct      network, that is, a link that is not part of the transport network      that is being managed.  For example, the nodes in the transport      network can be interconnected in two distinct physical networks:      the transport network and the DCN.   This is a "physically distinct out-of-band CCh".   2. The CCh can be provided by a link in the transport network that is      terminated at the ends of the DCC and that is capable of      encapsulating and terminating packets of the management protocols.      For example, in MPLS-TP, a single-hop LSP might be established      between two adjacent nodes, and that LSP might be capable of      carrying IP traffic.  Management traffic can then be inserted into      the link in an LSP parallel to the LSPs that carry user traffic.   This is a "physically shared out-of-band CCh."   3. The CCh can be supported as its native protocol on the interface      alongside the transported traffic.  For example, if an interface      is capable of sending and receiving both MPLS-TP and IP, the IP-      based management traffic can be sent as native IP packets on the      interface.   This is a "shared interface out-of-band CCh".   4. The CCh can use overhead bytes available on a transport      connection.  For example, in TDM networks there are overhead bytes      associated with a data channel, and these can be used to provide a      CCh.  It is important to note that the use of overhead bytes does      not reduce the capacity of the associated data channel.   This is an "overhead-based CCh".   This alternative is not available in MPLS-TP because there is no   overhead available.   5. The CCh can be provided by a dedicated channel associated with the      data link.  For example, the generic associated label (GAL) [14]      can be used to label DCC traffic being exchanged on a data link      between adjacent transport nodes, potentially in the absence of      any data LSP between those nodes.Lam, et al.                  Standards Track                   [Page 22]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   This is a "data link associated CCh".   It is very similar to case 2, and by its nature can only span a   single hop in the transport network.   6. The CCh can be provided by a dedicated channel associated with a      data channel.  For example, in MPLS-TP, the GAL [14] can be      imposed under the top label in the label stack for an MPLS-TP LSP      to create a channel associated with the LSP that can carry      management traffic.  This CCh requires the receiver to be capable      of demultiplexing management traffic from user traffic carried on      the same LSP by use of the GAL.   This is a "data channel associated CCh".   7. The CCh can be provided by mixing the management traffic with the      user traffic such that is indistinguishable on the link without      deep-packet inspection.  In MPLS-TP, this could arise if there is      a data-carrying LSP between two nodes, and management traffic is      inserted into that LSP.  This approach requires that the      termination point of the LSP be able to demultiplex the management      and user traffic.  This might be possible in MPLS-TP if the MPLS-      TP LSP is carrying IP user traffic.   This is an "in-band CCh".   These realizations can be categorized as:      A. Out-of-fiber, out-of-band (types 1 and 2)      B. In-fiber, out-of-band (types 2, 3, 4, and 5)      C. In-band (types 6 and 7)   The MCN and SCN are logically separate networks and can be realized   by the same DCN or as separate networks.  In practice, that means   that, between any pair of nodes, the MCC and SCC can be the same link   or separate links.   It is also important to note that the MCN and SCN do not need to be   categorised as in-band, out-of-band, etc.  This definition only   applies to the individual links, and it is possible for some nodes to   be connected in the MCN or SCN by one type of link, and other nodes   by other types of link.  Furthermore, a pair of adjacent nodes can be   connected by multiple links of different types.   Lastly, note that the division of DCN traffic between links between a   pair of adjacent nodes is purely an implementation choice.  Parallel   links can be deployed for DCN resilience or load sharing.  Links can   be designated for specific use.  For example, so that some linksLam, et al.                  Standards Track                   [Page 23]

RFC 5951        NM Requirements for MPLS-based Transport  September 2010   carry management traffic and some carry control plane traffic, or so   that some links carry signaling protocol traffic while others carry   routing protocol traffic.   It is important to note that the DCN can be a routed network with   forwarding capabilities, but that this is not a requirement.  The   ability to support forwarding of management or control traffic within   the DCN can substantially simplify the topology of the DCN and   improve its resilience, but does increase the complexity of operating   the DCN.   See alsoRFC 3877 [11], ITU-T M.20 [12], and Telcordia document   GR-833-CORE [13] for further information.Contributor's Address   Adrian Farrel   Old Dog Consulting   EMail: adrian@olddog.co.ukAuthors' Addresses   Eric Gray   Ericsson   900 Chelmsford Street   Lowell, MA, 01851   Phone: +1 978 275 7470   EMail: Eric.Gray@Ericsson.com   Scott Mansfield   Ericsson   250 Holger Way   San Jose CA, 95134   +1 724 931 9316   EMail: Scott.Mansfield@Ericsson.com   Hing-Kam (Kam) Lam   Alcatel-Lucent   600-700 Mountain Ave   Murray Hill, NJ, 07974   Phone: +1 908 582 0672   EMail: Kam.Lam@Alcatel-Lucent.comLam, et al.                  Standards Track                   [Page 24]