GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc5951

Internet Engineering Task Force (IETF) K. Lam Request for Comments: 5951 Alcatel-Lucent Category: Standards Track S. Mansfield ISSN: 2070-1721 E. Gray

                                                              Ericsson
                                                        September 2010
 Network Management Requirements for MPLS-based Transport Networks

Abstract

 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 in Section 2 of
 RFC 5741.
 Information about the current status of this document, any
 errata, and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc5951.

Lam, et al. Standards Track [Page 1] RFC 5951 NM Requirements for MPLS-based Transport September 2010

Copyright Notice

 Copyright (c) 2010 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Lam, et al. Standards Track [Page 2] RFC 5951 NM Requirements for MPLS-based Transport September 2010

Table of Contents

 1. Introduction ....................................................4
    1.1. Terminology ................................................5
 2. Management Interface Requirements ...............................7
 3. Management Communication Channel (MCC) Requirements .............7
 4. Management Communication Network (MCN) Requirements .............7
 5. Fault Management Requirements ...................................9
    5.1. Supervision Function .......................................9
    5.2. Validation Function .......................................10
    5.3. Alarm Handling Function ...................................11
         5.3.1. Alarm Severity Assignment ..........................11
         5.3.2. Alarm Suppression ..................................11
         5.3.3. Alarm Reporting ....................................11
         5.3.4. Alarm Reporting Control ............................12
 6. Configuration Management Requirements ..........................12
    6.1. System Configuration ......................................12
    6.2. Control Plane Configuration ...............................13
    6.3. Path Configuration ........................................13
    6.4. Protection Configuration ..................................14
    6.5. OAM Configuration .........................................14
 7. Performance Management Requirements ............................15
    7.1. Path Characterization Performance Metrics .................15
    7.2. Performance Measurement Instrumentation ...................16
         7.2.1. Measurement Frequency ..............................16
         7.2.2. Measurement Scope ..................................17
 8. Security Management Requirements ...............................17
    8.1. Management Communication Channel Security .................17
    8.2. Signaling Communication Channel Security ..................18
    8.3. Distributed Denial of Service .............................18
 9. Security Considerations ........................................19
 10. Acknowledgments ...............................................19
 11. References ....................................................19
    11.1. Normative References .....................................19
    12.2. Informative References ...................................20
 Appendix A.  Communication Channel (CCh) Examples..................22
 Contributor's Address .............................................24

Lam, et al. Standards Track [Page 3] RFC 5951 NM Requirements for MPLS-based Transport September 2010

1. 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] and RFC 4377 [2], and attempts to comply with
 the guidelines defined in RFC 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]
 and RFC 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 2010

1.1. 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 in RFC 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.  See Appendix 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.
 See RFC 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] - Sections 3.45 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 in section 3) MPLS-TP NEs
 with MPLS-TP NEs.

Lam, et al. Standards Track [Page 7] RFC 5951 NM Requirements for MPLS-based Transport September 2010

 RFC 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 in Section 7.1.1;
    b) MPLS-TP SCC data-link layer termination functions specified in
       Section 7.1.2.3;
    c) MPLS-TP MCC data-link layer termination functions specified in
       Section 7.1.2.4;
    d) Network layer PDU into CCh data-link frame encapsulation
       functions specified in Section 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 (Section
       7.1.10) functions.
 As a practical matter, MCN connections will typically have addresses.
 See the section on Identifiers in RFC 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 in RFC
    5860 [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 2010

5.2. 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 (see Section 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 Function

5.3.1. 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 in RFC 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 in RFC 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) and RFC 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 in RFC 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 in RFC 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 Instrumentation

7.2.1. 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 2010

7.2.2. 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 (see RFC 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 in Section 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 2010

9. Security Considerations

 Section 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. References

11.1. 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", RFC
       3871, 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", RFC
       5950, 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 2010

Appendix 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 links

Lam, 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 also RFC 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.uk

Authors' 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.com

Lam, et al. Standards Track [Page 24]

/data/webs/external/dokuwiki/data/pages/rfc/rfc5951.txt · Last modified: 2010/09/14 18:53 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki