draft-ietf-mpls-tp-nm-req-02.txt   draft-ietf-mpls-tp-nm-req-03.txt 
Network Working Group Hing-Kam Lam Network Working Group Hing-Kam Lam
Internet Draft Alcatel-Lucent Internet Draft Alcatel-Lucent
Expires: December, 2009 Scott Mansfield Expires: March, 2010 Scott Mansfield
Intended Status: Standards Track Eric Gray Intended Status: Standards Track Eric Gray
Ericsson Ericsson
June 24, 2009 August 31, 2009
MPLS TP Network Management Requirements MPLS TP Network Management Requirements
draft-ietf-mpls-tp-nm-req-02.txt draft-ietf-mpls-tp-nm-req-03.txt
Status of this Memo Status of this Memo
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Abstract Abstract
This document specifies the requirements for the management of This document specifies the requirements for the management of
equipment used in networks supporting an MPLS Transport Profile equipment used in networks supporting an MPLS Transport Profile
(MPLS-TP). The requirements are defined for specification of (MPLS-TP). The requirements are defined for specification of
network management aspects of protocol mechanisms and procedures network management aspects of protocol mechanisms and procedures
that constitute the building blocks out of which the MPLS that constitute the building blocks out of which the MPLS
transport profile is constructed. That is, these requirements transport profile is constructed. That is, these requirements
indicate what management capabilities need to be available in indicate what management capabilities need to be available in
MPLS for use in managing the MPLS-TP. This document is intended MPLS for use in managing the MPLS-TP. This document is intended
to identify essential network management capabilities, not to to identify essential network management capabilities, not to
specify what functions any particular MPLS implementation specify what functions any particular MPLS implementation
supports. supports.
Table of Contents Table of Contents
1. Introduction................................................3 1. Introduction........................................3
1.1. Terminology............................................4 1.1. Terminology.....................................4
2. Management Interface Requirements...........................6 2. Management Interface Requirements......................6
3. Management Communication Channel (MCC) Requirements.........6 3. Management Communication Channel (MCC) Requirements.......6
4. Management Communication Network (MCN) Requirements.........6 4. Management Communication Network (MCN) Requirements.......6
5. Fault Management Requirements...............................8 5. Fault Management Requirements..........................8
5.1. Supervision Function...................................8 5.1. Supervision Function.............................8
5.2. Validation Function....................................9 5.2. Validation Function..............................9
5.3. Alarm Handling Function...............................10 5.3. Alarm Handling Function..........................10
5.3.1. Alarm Severity Assignment........................10 5.3.1. Alarm Severity Assignment....................10
5.3.2. Alarm Suppression................................10 5.3.2. Alarm Suppression ..........................10
5.3.3. Alarm Reporting..................................11 5.3.3. Alarm Reporting............................10
5.3.4. Alarm Reporting Control..........................11 5.3.4. Alarm Reporting Control.....................11
6. Configuration Management Requirements......................11 6. Configuration Management Requirements..................11
6.1. System Configuration..................................12 6.1. System Configuration............................11
6.2. Control Plane Configuration...........................12 6.2. Control Plane Configuration......................12
6.3. Path Configuration....................................12 6.3. Path Configuration..............................12
6.4. Protection Configuration..............................13 6.4. Protection Configuration.........................13
6.5. OAM Configuration.....................................13 6.5. OAM Configuration...............................13
7. Performance Management Requirements........................14 7. Performance Management Requirements....................14
7.1. Path Characterization Performance Metrics.............14 7.1. Path Characterization Performance Metrics..........14
7.2. Performance Measurement Instrumentation...............15 7.2. Performance Measurement Instrumentation............16
7.2.1. Measurement Frequency............................15 7.2.1. Measurement Frequency.......................16
7.2.2. Measurement Scope................................16 7.2.2. Measurement Scope ..........................16
8. Security Management Requirements...........................16 8. Security Management Requirements......................16
8.1. Management Communication Channel Security.............16 8.1. Management Communication Channel Security..........16
8.2. Signaling Communication Channel Security..............17 8.2. Signaling Communication Channel Security...........17
8.3. Distributed Denial of Service.........................17 8.3. Distributed Denial of Service ....................17
9. Security Considerations....................................18 9. Security Considerations..............................18
10. IANA Considerations.......................................18 10. IANA Considerations................................18
11. Acknowledgments...........................................18 11. Acknowledgments....................................18
12. References................................................18 12. References........................................18
12.1. Normative References.................................18 12.1. Normative References...........................18
12.2. Informative References...............................19 12.2. Informative References..........................19
Author's Addresses............................................21 Author's Addresses.....................................21
Copyright Statement...........................................21 Copyright Statement....................................21
Acknowledgment................................................22 Acknowledgment........................................22
APPENDIX A: Communication Channel (CCh) Examples..............23 Appendix A - Communication Channel (CCh) Examples..........23
1. Introduction 1. Introduction
This document specifies the requirements for the management of This document specifies the requirements for the management of
equipment used in networks supporting an MPLS Transport Profile equipment used in networks supporting an MPLS Transport Profile
(MPLS-TP). The requirements are defined for specification of (MPLS-TP). The requirements are defined for specification of
network management aspects of protocol mechanisms and procedures network management aspects of protocol mechanisms and procedures
that constitute the building blocks out of which the MPLS that constitute the building blocks out of which the MPLS
transport profile is constructed. That is, these requirements transport profile is constructed. That is, these requirements
indicate what management capabilities need to be available in indicate what management capabilities need to be available in
MPLS for use in managing the MPLS-TP. This document is intended MPLS for use in managing the MPLS-TP. This document is intended
to identify essential network management capabilities, not to to identify essential network management capabilities, not to
specify what functions any particular MPLS implementation specify what functions any particular MPLS implementation
supports. supports.
This document also leverages management requirements specified This document also leverages management requirements specified
in ITU-T G.7710/Y.1701 [1] and RFC 4377 [2], and attempts to in ITU-T G.7710/Y.1701 [1] and RFC 4377 [2], and attempts to
comply with best common practice as defined in [18]. comply with best common practice as defined in [14].
ITU-T G.7710/Y.1701 defines generic management requirements for ITU-T G.7710/Y.1701 defines generic management requirements for
transport networks. RFC 4377 specifies the OAM requirements, transport networks. RFC 4377 specifies the OAM requirements,
including OAM-related network management requirements, for MPLS including OAM-related network management requirements, for MPLS
networks. networks.
This document is a product of a joint ITU-T and IETF effort to 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 include an MPLS Transport Profile (MPLS-TP) within the IETF MPLS
and PWE3 architectures to support capabilities and functionality and PWE3 architectures to support capabilities and functionality
of a transport network as defined by ITU-T. of a transport network as defined by ITU-T.
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defined herein. Related functions of MPLS and PWE3 are defined defined herein. Related functions of MPLS and PWE3 are defined
elsewhere (and are out of scope in this document). elsewhere (and are out of scope in this document).
This document expands on the requirements in [1] and [2] to This document expands on the requirements in [1] and [2] to
cover fault, configuration, performance, and security management cover fault, configuration, performance, and security management
for MPLS-TP networks, and the requirements for object and for MPLS-TP networks, and the requirements for object and
information models needed to manage MPLS-TP Networks and Network information models needed to manage MPLS-TP Networks and Network
Elements. Elements.
In writing this document, the authors assume the reader is In writing this document, the authors assume the reader is
familiar with references [19] and [20]. familiar with references [12] and [15].
1.1. Terminology 1.1. Terminology
Although this document is not a protocol specification, the key Although this document is not a protocol specification, the key
words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119 [6] this document are to be interpreted as described in RFC 2119 [5]
and are to be interpreted as instructions to protocol designers and are to be interpreted as instructions to protocol designers
producing solutions that satisfy the requirements set out in producing solutions that satisfy the requirements set out in
this document. this document.
Anomaly: The smallest discrepancy which can be observed between Anomaly: The smallest discrepancy which can be observed between
actual and desired characteristics of an item. The occurrence of actual and desired characteristics of an item. The occurrence of
a single anomaly does not constitute an interruption in ability a single anomaly does not constitute an interruption in ability
to perform a required function. Anomalies are used as the input to perform a required function. Anomalies are used as the input
for the Performance Monitoring (PM) process and for detection of for the Performance Monitoring (PM) process and for detection of
defects ([27], 3.7). defects (from [21], 3.7).
Communication Channel (CCh): A logical channel between network Communication Channel (CCh): A logical channel between network
elements (NEs) that can be used - e.g. - for management or elements (NEs) that can be used - e.g. - for management or
control plane applications. The physical channel supporting the control plane applications. The physical channel supporting the
CCh is technology specific. See APPENDIX A: CCh is technology specific. See Appendix A.
Data Communication Network (DCN): A network that supports Layer Data Communication Network (DCN): A network that supports Layer
1 (physical layer), Layer 2 (data-link layer), and Layer 3 1 (physical layer), Layer 2 (data-link layer), and Layer 3
(network layer) functionality for distributed management (network layer) functionality for distributed management
communications related to the management plane, for distributed communications related to the management plane, for distributed
signaling communications related to the control plane, and other signaling communications related to the control plane, and other
operations communications (e.g., order-wire/voice operations communications (e.g., order-wire/voice
communications, software downloads, etc.). communications, software downloads, etc.).
Defect: The density of anomalies has reached a level where the Defect: The density of anomalies has reached a level where the
ability to perform a required function has been interrupted. ability to perform a required function has been interrupted.
Defects are used as input for performance monitoring, the Defects are used as input for performance monitoring, the
control of consequent actions, and the determination of fault control of consequent actions, and the determination of fault
cause ([27], 3.24). cause (from [21], 3.24).
Failure: The fault cause persisted long enough to consider the Failure: The fault cause persisted long enough to consider the
ability of an item to perform a required function to be ability of an item to perform a required function to be
terminated. The item may be considered as failed; a fault has terminated. The item may be considered as failed; a fault has
now been detected ([27], 3.25). now been detected (from [21], 3.25).
Fault: A fault is the inability of a function to perform a Fault: A fault is the inability of a function to perform a
required action. This does not include an inability due to required action. This does not include an inability due to
preventive maintenance, lack of external resources, or planned preventive maintenance, lack of external resources, or planned
actions ([27], 3.26). actions (from [21], 3.26).
Fault Cause: A single disturbance or fault may lead to the Fault Cause: A single disturbance or fault may lead to the
detection of multiple defects. A fault cause is the result of a detection of multiple defects. A fault cause is the result of a
correlation process which is intended to identify the defect correlation process which is intended to identify the defect
that is representative of the disturbance or fault that is that is representative of the disturbance or fault that is
causing the problem ([27], 3.27). causing the problem (from [21], 3.27).
Fault Cause Indication (FCI): An indication of a fault cause. Fault Cause Indication (FCI): An indication of a fault cause.
Management Communication Channel (MCC): A CCh dedicated for Management Communication Channel (MCC): A CCh dedicated for
management plane communications. management plane communications.
Management Communication Network (MCN): A DCN supporting Management Communication Network (MCN): A DCN supporting
management plane communication is referred to as a Management management plane communication is referred to as a Management
Communication Network (MCN). Communication Network (MCN).
MPLS-TP NE: A network element (NE) that supports the functions MPLS-TP NE: A network element (NE) that supports the functions
of MPLS necessary to participate in an MPLS-TP based transport of MPLS necessary to participate in an MPLS-TP based transport
service. See [24] for further information on functionality service. See [8] for further information on functionality
required to support MPLS-TP. required to support MPLS-TP.
MPLS-TP network: A network in which MPLS-TP NEs are deployed. MPLS-TP network: a network in which MPLS-TP NEs are deployed.
OAM, On-Demand and Proactive: One feature of OAM that is largely OAM, On-Demand and Proactive: One feature of OAM that is largely
a management issue is control of OAM; on-demand and proactive a management issue is control of OAM; on-demand and proactive
are modes of OAM mechanism operation defined - for example - in are modes of OAM mechanism operation defined - for example - in
Y.1731 ([28] - 3.45 and 3.44 respectively) as: Y.1731 ([22] - 3.45 and 3.44 respectively) as:
- On-demand OAM - OAM actions which are initiated via manual . On-demand OAM - OAM actions which are initiated via manual
intervention for a limited time to carry out diagnostics. intervention for a limited time to carry out diagnostics.
On-demand OAM can result in singular or periodic OAM On-demand OAM can result in singular or periodic OAM
actions during the diagnostic time interval. actions during the diagnostic time interval.
- Proactive OAM - OAM actions which are carried on . Proactive OAM - OAM actions which are carried on
continuously to permit timely reporting of fault and/or continuously to permit timely reporting of fault and/or
performance status. performance status.
(Note that it is possible for specific OAM mechanisms to only (Note that it is possible for specific OAM mechanisms to only
have a sensible use in either on-demand or proactive mode.) have a sensible use in either on-demand or proactive mode.)
Operations System (OS): A system that performs the functions Operations System (OS): A system that performs the functions
that support processing of information related to operations, that support processing of information related to operations,
administration, maintenance, and provisioning (OAM&P) for the administration, maintenance, and provisioning (OAM&P) for the
networks, including surveillance and testing functions to networks, including surveillance and testing functions to
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Signaling Communication Network (SCN): A DCN supporting control Signaling Communication Network (SCN): A DCN supporting control
plane communication is referred to as a Signaling Communication plane communication is referred to as a Signaling Communication
Network (SCN). Network (SCN).
2. Management Interface Requirements 2. Management Interface Requirements
This document does not specify which management interface This document does not specify which management interface
protocol should be used as the standard protocol for managing protocol should be used as the standard protocol for managing
MPLS-TP networks. Managing an end-to-end connection across MPLS-TP networks. Managing an end-to-end connection across
multiple operator domains where one domain is managed (for multiple operator domains where one domain is managed (for
example) via NETCONF/XML ([21]) or SNMP/SMI ([22]), and another example) via NETCONF/XML ([16]) or SNMP/SMI ([17]), and another
domain via CORBA/IDL ([23]), is allowed. domain via CORBA/IDL ([18]), is allowed.
For the management interface to the management system, an MPLS- For the management interface to the management system, an MPLS-
TP NE MAY actively support more than one management protocol in TP NE MAY actively support more than one management protocol in
any given deployment. For example, an MPLS-TP NE may use one any given deployment. For example, an MPLS-TP NE may use one
protocol for configuration and another for monitoring. The protocol for configuration and another for monitoring. The
protocols to be supported are at the discretion of the operator. protocols to be supported are at the discretion of the operator.
3. Management Communication Channel (MCC) Requirements 3. Management Communication Channel (MCC) Requirements
Specifications SHOULD define support for management connectivity Specifications SHOULD define support for management connectivity
with remote MPLS-TP domains and NEs, as well as with termination with remote MPLS-TP domains and NEs, as well as with termination
points located in NEs under the control of a third party network points located in NEs under the control of a third party network
operator. See ITU-T G.8601 [8] for example scenarios in multi- operator. See ITU-T G.8601 [23] for example scenarios in multi-
carrier multi-transport-technology environments. carrier multi-transport-technology environments.
For management purpose, every MPLS-TP NE MUST connect to an OS. For management purpose, every MPLS-TP NE MUST connect to an OS.
The connection MAY be direct (e.g. - via a software, hardware or The connection MAY be direct (e.g. - via a software, hardware or
proprietary protocol connection) or indirect (via another MPLS- proprietary protocol connection) or indirect (via another MPLS-
TP NE). In this document, any management connection that is not TP NE). In this document, any management connection that is not
via another MPLS-TP NE is a direct management connection. When 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 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 supported between that MPLS-TP NE and any MPLS-TP NE(s) used to
provide the connection to an OS. provide the connection to an OS.
4. Management Communication Network (MCN) Requirements 4. Management Communication Network (MCN) Requirements
Entities of the MPLS-TP management plane communicate via a DCN, Entities of the MPLS-TP management plane communicate via a DCN,
or more specifically via the MCN. The MCN connects management or more specifically via the MCN. The MCN connects management
systems with management systems, management systems with MPLS-TP systems with management systems, management systems with MPLS-TP
NEs, and (in the indirect connectivity case discussed in section NEs, and (in the indirect connectivity case discussed in section
3) MPLS-TP NEs with MPLS-TP NEs. 3) MPLS-TP NEs with MPLS-TP NEs.
RFC 5586 ([10]) defines a Generic Associated Channel (G-ACh) to RFC 5586 (Error! Reference source not found.) defines a Generic
enable the realization of a communication channel (CCh) between Associated Channel (G-ACh) to enable the realization of a
adjacent MPLS-TP NEs for management and control. Reference [11] communication channel (CCh) between adjacent MPLS-TP NEs for
describes how the G-ACh may be used to provide infrastructure management and control. Reference [7] describes how the G-ACh
that forms part of the MCN and a SCN. It also explains how MCN may be used to provide infrastructure that forms part of the MCN
and SCN messages are encapsulated, carried on the G-ACh, and and SCN. It also explains how MCN and SCN messages are
demultiplexed for delivery to management or signaling/routing encapsulated, carried on the G-ACh, and decapsulated for
control plane components on a label switching router (LSR). delivery to management or signaling/routing control plane
components on a label switching router (LSR).
ITU-T G.7712/Y.1703 [7], section 7, describes the transport DCN ITU-T G.7712/Y.1703 [6], section 7, describes the transport DCN
architecture and requirements. The MPLS-TP MCN MUST support the architecture and requirements. The MPLS-TP MCN MUST support the
requirements (in reference [7]) for: requirements (in reference [6]) for:
- CCh access functions specified in section 7.1.1; - CCh access functions specified in section 7.1.1;
- MPLS-TP SCC data-link layer termination functions specified - MPLS-TP SCC data-link layer termination functions specified
in section 7.1.2.3; in section 7.1.2.3;
- MPLS-TP MCC data-link layer termination functions specified - MPLS-TP MCC data-link layer termination functions specified
in section 7.1.2.4; in section 7.1.2.4;
- Network layer PDU into CCh data-link frame encapsulation - Network layer PDU into CCh data-link frame encapsulation
functions specified in section 7.1.3; functions specified in section 7.1.3;
- Network layer PDU forwarding (7.1.6), interworking (7.1.7) - Network layer PDU forwarding (7.1.6), interworking (7.1.7)
and encapsulation (7.1.8) functions, as well as tunneling and encapsulation (7.1.8) functions, as well as tunneling
(7.1.9) and routing (7.1.10) functions specified in [7]. (7.1.9) and routing (7.1.10) functions specified in [6].
As a practical matter, MCN connections will typically have As a practical matter, MCN connections will typically have
addresses. See the section on addressing in [15] for further addresses. See the section on addressing in [15] for further
information. information.
In order to have the MCN operate properly, a number of In order to have the MCN operate properly, a number of
management functions for the MCN are needed, including: management functions for the MCN are needed, including:
- Retrieval of DCN network parameters to ensure compatible . Retrieval of DCN network parameters to ensure compatible
functioning, e.g. packet size, timeouts, quality of functioning, e.g. packet size, timeouts, quality of
service, window size, etc.; service, window size, etc.;
- Establishment of message routing between DCN nodes; . Establishment of message routing between DCN nodes;
- Management of DCN network addresses; . Management of DCN network addresses;
. Retrieval of operational status of the DCN at a given node;
- Retrieval of operational status of the DCN at a given node; . Capability to enable/disable access by an NE to the DCN.
- Capability to enable/disable access by an NE to the DCN.
Note that this is to allow isolating a malfunctioning NE Note that this is to allow isolating a malfunctioning NE
from impacting the rest of the network. from impacting the rest of the network.
5. Fault Management Requirements 5. Fault Management Requirements
The Fault Management functions within an MPLS-TP NE enable the The Fault Management functions within an MPLS-TP NE enable the
supervision, detection, validation, isolation, correction, and supervision, detection, validation, isolation, correction, and
reporting of abnormal operation of the MPLS-TP network and its reporting of abnormal operation of the MPLS-TP network and its
environment. environment.
5.1. Supervision Function 5.1. Supervision Function
The supervision function analyses the actual occurrence of a The supervision function analyses the actual occurrence of a
disturbance or fault for the purpose of providing an appropriate disturbance or fault for the purpose of providing an appropriate
indication of performance and/or detected fault condition to indication of performance and/or detected fault condition to
maintenance personnel and operations systems. maintenance personnel and operations systems.
The MPLS-TP NE MUST support supervision of the OAM mechanisms The MPLS-TP NE MUST support supervision of the OAM mechanisms
that are deployed for supporting the OAM requirements defined in that are deployed for supporting the OAM requirements defined in
[3]. [1].
The MPLS-TP NE MUST support the following data-plane forwarding The MPLS-TP NE MUST support the following data-plane forwarding
path supervision functions: path supervision functions:
- Supervision of loop-checking functions used to detect loops . Supervision of loop-checking functions used to detect loops
in the data-plane forwarding path (which result in non- in the data-plane forwarding path (which result in non-
delivery of traffic, wasting of forwarding resources and delivery of traffic, wasting of forwarding resources and
unintended self-replication of traffic); unintended self-replication of traffic);
- Supervision of failure detection; . Supervision of failure detection;
The MPLS-TP NE MUST support the capability to configure data- The MPLS-TP NE MUST support the capability to configure data-
plane forwarding path related supervision mechanisms to perform plane forwarding path related supervision mechanisms to perform
on-demand or proactively. on-demand or proactively.
The MPLS-TP NE MUST support supervision for software processing The MPLS-TP NE MUST support supervision for software processing
e.g., processing faults, storage capacity, version mismatch, e.g., processing faults, storage capacity, version mismatch,
corrupted data and out of memory problems, etc. corrupted data and out of memory problems, etc.
The MPLS-TP NE MUST support hardware-related supervision for The MPLS-TP NE MUST support hardware-related supervision for
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Time-C = 10 +/- 0.5 seconds Time-C = 10 +/- 0.5 seconds
These time values are as defined in G.7710 [1]. These time values are as defined in G.7710 [1].
MIBs - or other object management semantics specifications - MIBs - or other object management semantics specifications -
defined to enable configuration of these timers SHOULD defined to enable configuration of these timers SHOULD
explicitly provide default values and MAY provide guidelines on explicitly provide default values and MAY provide guidelines on
ranges and value determination methods for scenarios where the ranges and value determination methods for scenarios where the
default value chosen might be inadequate. In addition, such default value chosen might be inadequate. In addition, such
specifications SHOULD define the level of granularity at which specifications SHOULD define the level of granularity at which
tables of these values are to be defined. Examples of levels of tables of these values are to be defined.
granularity MAY include per-failure-cause and per-deduced-fault.
Implementations MUST provide the ability to configure the Implementations MUST provide the ability to configure the
preceding set of timers, and SHOULD provide default values to preceding set of timers, and SHOULD provide default values to
enable rapid configuration. Suitable default values, timer enable rapid configuration. Suitable default values, timer
ranges, and level of granularity are out of scope in this ranges, and level of granularity are out of scope in this
document and form part of the specification of fault management document and form part of the specification of fault management
details. Timers SHOULD be configurable per NE for broad details. Timers SHOULD be configurable per NE for broad
categories of failure causes and deduced faults, and MAY be categories (for example, defects and/or fault causes), and MAY
configurable per-interface on an NE or per individual failure be configurable per-interface on an NE and/or per individual
cause or deduced fault. defect/fault cause.
The failure declaration and clearing MUST be time stamped. The The failure declaration and clearing MUST be time stamped. The
time-stamp MUST indicate the time at which the fault cause is time-stamp MUST indicate the time at which the fault cause is
activated at the input of the fault cause persistency (i.e. activated at the input of the fault cause persistency (i.e.
defect-to-failure integration) function, and the time at which defect-to-failure integration) function, and the time at which
the fault cause is deactivated at the input of the fault cause the fault cause is deactivated at the input of the fault cause
persistency function. persistency function.
5.3. Alarm Handling Function 5.3. Alarm Handling Function
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Alarm Reporting Control (ARC) supports an automatic in-service Alarm Reporting Control (ARC) supports an automatic in-service
provisioning capability. Alarm reporting can be turned off on a provisioning capability. Alarm reporting can be turned off on a
per-managed entity (e.g., LSP) basis to allow sufficient time per-managed entity (e.g., LSP) basis to allow sufficient time
for customer service testing and other maintenance activities in for customer service testing and other maintenance activities in
an "alarm free" state. Once a managed entity is ready, alarm an "alarm free" state. Once a managed entity is ready, alarm
reporting is automatically turned on. reporting is automatically turned on.
An MPLS-TP NE SHOULD support the Alarm Reporting Control An MPLS-TP NE SHOULD support the Alarm Reporting Control
function for controlling the reporting of alarm conditions. function for controlling the reporting of alarm conditions.
See G.7710 [1] (section 7.1.3.2) and RFC 3878 [9] for more See G.7710 [1] (section 7.1.3.2) and RFC 3878 [24] for more
information about ARC. information about ARC.
6.Configuration Management Requirements 6.Configuration Management Requirements
Configuration Management provides functions to identify, collect Configuration Management provides functions to identify, collect
data from, provide data to and control NEs. Specific data from, provide data to and control NEs. Specific
configuration tasks requiring network management support include configuration tasks requiring network management support include
hardware and software configuration, configuration of NEs to hardware and software configuration, configuration of NEs to
support transport paths (including required working and support transport paths (including required working and
protection paths), and configuration of required path protection paths), and configuration of required path
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If a control plane is supported in an implementation of MPLS-TP, If a control plane is supported in an implementation of MPLS-TP,
the MPLS-TP NE MUST support the configuration of MPLS-TP control the MPLS-TP NE MUST support the configuration of MPLS-TP control
plane functions by the management plane. Further detailed plane functions by the management plane. Further detailed
requirements will be provided along with progress in defining requirements will be provided along with progress in defining
the MPLS-TP control plane in appropriate specifications. the MPLS-TP control plane in appropriate specifications.
6.3. Path Configuration 6.3. Path Configuration
In addition to the requirement to support static provisioning of In addition to the requirement to support static provisioning of
transport paths (defined in [24], section 2.1 - General transport paths (defined in [8], section 2.1 - General
Requirements - requirement 18), an MPLS-TP NE MUST support the Requirements - requirement 18), an MPLS-TP NE MUST support the
configuration of required path performance characteristic configuration of required path performance characteristic
thresholds (e.g. - Loss Measurement [LM], Delay Measurement [DM] thresholds (e.g. - Loss Measurement [LM], Delay Measurement [DM]
thresholds) necessary to support performance monitoring of the thresholds) necessary to support performance monitoring of the
MPLS-TP service(s). MPLS-TP service(s).
In order to accomplish this, an MPLS-TP NE MUST support In order to accomplish this, an MPLS-TP NE MUST support
configuration of LSP information (such as an LSP identifier of configuration of LSP information (such as an LSP identifier of
some kind) and/or any other information needed to retrieve LSP some kind) and/or any other information needed to retrieve LSP
status information, performance attributes, etc. status information, performance attributes, etc.
If a control plane is supported, and that control plane includes If a control plane is supported, and that control plane includes
support for control-plane/management-plane hand-off for LSP support for control-plane/management-plane hand-off for LSP
setup/maintenance, the MPLS-TP NE MUST support management of the setup/maintenance, the MPLS-TP NE MUST support management of the
hand-off of Path control. See, for example, references [25] and hand-off of Path control. See, for example, references [19] and
[26]. [20].
Further detailed requirements will be provided along with Further detailed requirements will be provided along with
progress in defining the MPLS-TP control plane in appropriate progress in defining the MPLS-TP control plane in appropriate
specifications. specifications.
If MPLS-TP transport paths cannot be statically provisioned If MPLS-TP transport paths cannot be statically provisioned
using MPLS LSP and pseudo-wire management tools (either already using MPLS LSP and pseudo-wire management tools (either already
defined in standards or under development), further management defined in standards or under development), further management
specifications MUST be provided as needed. specifications MUST be provided as needed.
6.4. Protection Configuration 6.4. Protection Configuration
The MPLS-TP NE MUST support configuration of required path The MPLS-TP NE MUST support configuration of required path
protection information as follows: protection information as follows:
- designate specifically identified LSPs as working or . designate specifically identified LSPs as working or
protection LSPs; protecting LSPs;
- define associations of working and protection paths; . define associations of working and protecting paths;
- operate/release manual protection switching; . operate/release manual protection switching;
- operate/release force protection switching; . operate/release force protection switching;
- operate/release protection lockout; . operate/release protection lockout;
- set/retrieve Automatic Protection Switching (APS) . set/retrieve Automatic Protection Switching (APS)
parameters, including - parameters, including -
o Wait to Restore time, o Wait to Restore time,
o Protection Switching threshold information. o Protection Switching threshold information.
6.5. OAM Configuration 6.5. OAM Configuration
The MPLS-TP NE MUST support configuration of the OAM entities The MPLS-TP NE MUST support configuration of the OAM entities
and functions specified in [3]. and functions specified in [3].
The MPLS-TP NE MUST support the capability to choose which OAM The MPLS-TP NE MUST support the capability to choose which OAM
functions to use and which maintenance entity will apply them. functions are enabled.
For enabled OAM functions, the MPLS-TP NE MUST support the
ability to associate OAM functions with specific maintenance
entities.
The MPLS-TP NE MUST support the capability to configure the OAM The MPLS-TP NE MUST support the capability to configure the OAM
entities/functions as part of LSP setup and tear-down, including entities/functions as part of LSP setup and tear-down, including
co-routed bidirectional point-to-point, associated bidirectional co-routed bidirectional point-to-point, associated bidirectional
point-to-point, and uni-directional (both point-to-point and point-to-point, and uni-directional (both point-to-point and
point-to-multipoint) connections. point-to-multipoint) connections.
The MPLS-TP NE MUST support the configuration of maintenance The MPLS-TP NE MUST support the configuration of maintenance
entity identifiers (e.g. MEP ID and MIP ID) for the purpose of entity identifiers (e.g. MEP ID and MIP ID) for the purpose of
LSP connectivity checking. LSP connectivity checking.
skipping to change at page 15, line 14 skipping to change at page 15, line 17
extent that a configurable performance threshold has been extent that a configurable performance threshold has been
crossed and the degradation persists long enough (i.e. - the crossed and the degradation persists long enough (i.e. - the
indication persists for some amount of time - which is either indication persists for some amount of time - which is either
configurable, or well-known) to be certain it is not a configurable, or well-known) to be certain it is not a
measurement anomaly. measurement anomaly.
Methods, mechanisms and algorithms for exactly how Methods, mechanisms and algorithms for exactly how
unavailability is to be determined - based on collection of raw unavailability is to be determined - based on collection of raw
performance data - are out of scope for this document. performance data - are out of scope for this document.
For the purposes of this document, it is sufficient to state The MPLS-TP NE MUST support collection and reporting of raw
that an MPLS-TP NE MUST support collection, and reporting, of performance data that MAY be used in determining the
raw performance data that MAY be used in determining unavailability of a transport service.
availability of a transport service, and that implementations
SHOULD support some as yet to be defined mechanism for MPLS-TP MUST support the determination of the unavailability of
determining service availability. 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 availability-state of services.
Transport network unavailability is based on Severely Errored
Seconds (SES) and Unavailable Seconds (UAS). ITU-T is
establishing definitions of unavailability 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].
The MPLS-TP NE MUST support collection of loss measurement (LM) The MPLS-TP NE MUST support collection of loss measurement (LM)
statistics. statistics.
The MPLS-TP NE MUST support collection of delay measurement (DM) The MPLS-TP NE MUST support collection of delay measurement (DM)
statistics. statistics.
The MPLS-TP NE MUST support reporting of Performance degradation The MPLS-TP NE MUST support reporting of Performance degradation
via fault management for corrective actions. "Reporting" in this via fault management for corrective actions. "Reporting" in this
context could mean: context could mean:
- reporting to an autonomous protection component to trigger . reporting to an autonomous protection component to trigger
protection switching, protection switching,
- reporting via a craft interface to allow replacement of a . reporting via a craft interface to allow replacement of a
faulty component (or similar manual intervention), faulty component (or similar manual intervention),
. etc.
- etc.
The MPLS-TP NE MUST support reporting of performance statistics The MPLS-TP NE MUST support reporting of performance statistics
on request from a management system. on request from a management system.
7.2. Performance Measurement Instrumentation 7.2. Performance Measurement Instrumentation
7.2.1. Measurement Frequency 7.2.1. Measurement Frequency
For performance measurement mechanisms that support both For performance measurement mechanisms that support both
proactive and on-demand modes, the MPLS-TP NE MUST support the proactive and on-demand modes, the MPLS-TP NE MUST support the
capability to be configured to operate on-demand or proactively. capability to be configured to operate on-demand or proactively.
7.2.2. Measurement Scope 7.2.2. Measurement Scope
On measurement of packet loss and loss ratio: On measurement of packet loss and loss ratio:
- For bidirectional (both co-routed and associated) P2P . For bidirectional (both co-routed and associated) P2P
connections - connections -
o on-demand measurement of single-ended packet loss, and o on-demand measurement of single-ended packet loss, and
loss ratio, measurement is REQUIRED; loss ratio, measurement is REQUIRED;
o proactive measurement of packet loss, and loss ratio, o proactive measurement of packet loss, and loss ratio,
measurement for each direction is REQUIRED. measurement for each direction is REQUIRED.
- for unidirectional (P2P and P2MP) connection, proactive . for unidirectional (P2P and P2MP) connection, proactive
measurement of packet loss, and loss ratio, is REQUIRED. measurement of packet loss, and loss ratio, is REQUIRED.
On Delay measurement: On Delay measurement:
- for unidirectional (P2P and P2MP) connection, on-demand . for unidirectional (P2P and P2MP) connection, on-demand
measurement of delay measurement is REQUIRED. measurement of delay measurement is REQUIRED.
- for co-routed bidirectional (P2P) connection, on-demand . for co-routed bidirectional (P2P) connection, on-demand
measurement of one-way and two-way delay is REQUIRED. measurement of one-way and two-way delay is REQUIRED.
- for associated bidirectional (P2P) connection, on-demand . for associated bidirectional (P2P) connection, on-demand
measurement of one-way delay is REQUIRED. measurement of one-way delay is REQUIRED.
8. Security Management Requirements 8. Security Management Requirements
The MPLS-TP NE MUST support secure management and control The MPLS-TP NE MUST support secure management and control
planes. planes.
8.1. Management Communication Channel Security 8.1. Management Communication Channel Security
Secure communication channels MUST be supported for all network Secure communication channels MUST be supported for all network
traffic and protocols used to support management functions. traffic and protocols used to support management functions.
This MUST include, at least, protocols used for configuration, This MUST include, at least, protocols used for configuration,
monitoring, configuration backup, logging, time synchronization, monitoring, configuration backup, logging, time synchronization,
authentication, and routing. The MCC MUST support application authentication, and routing. The MCC MUST support application
protocols that provide confidentiality and data integrity protocols that provide confidentiality and data integrity
protection. protection.
The MPLS-TP NE MUST support the following: The MPLS-TP NE MUST support the following:
- Use of open cryptographic algorithms (See RFC 3871 [5]) - Use of open cryptographic algorithms (See RFC 3871 [4])
- Authentication - allow management connectivity only from - Authentication - allow management connectivity only from
authenticated entities. authenticated entities.
- Authorization - allow management activity originated by an - Authorization - allow management activity originated by an
authorized entity, using (for example) an Access Control authorized entity, using (for example) an Access Control
List (ACL). List (ACL).
- Port Access Control - allow management activity received on - Port Access Control - allow management activity received on
an authorized (management) port. an authorized (management) port.
skipping to change at page 17, line 37 skipping to change at page 18, line 4
A Denial of Service (DoS) attack is an attack that tries to A Denial of Service (DoS) attack is an attack that tries to
prevent a target from performing an assigned task, or providing prevent a target from performing an assigned task, or providing
its intended service(s), through any means. A Distributed DoS its intended service(s), through any means. A Distributed DoS
(DDoS) can multiply attack severity (possibly by an arbitrary (DDoS) can multiply attack severity (possibly by an arbitrary
amount) by using multiple (potentially compromised) systems to amount) by using multiple (potentially compromised) systems to
act as topologically (and potentially geographically) act as topologically (and potentially geographically)
distributed attack sources. It is possible to lessen the impact distributed attack sources. It is possible to lessen the impact
and potential for DoS and DDoS by using secure protocols, and potential for DoS and DDoS by using secure protocols,
turning off unnecessary processes, logging and monitoring, and turning off unnecessary processes, logging and monitoring, and
ingress filtering. RFC 4732 [4] provides background on DOS in ingress filtering. RFC 4732 [26] provides background on DOS in
the context of the Internet. the context of the Internet.
An MPLS-TP NE MUST support secure management protocols and An MPLS-TP NE MUST support secure management protocols and
SHOULD do so in a manner the reduce potential impact of a DoS SHOULD do so in a manner the reduce potential impact of a DoS
attack. attack.
An MPLS-TP NE SHOULD support additional mechanisms that mitigate An MPLS-TP NE SHOULD support additional mechanisms that mitigate
a DoS (or DDoS) attack against the management component while a DoS (or DDoS) attack against the management component while
allowing the NE to continue to meet its primary functions. allowing the NE to continue to meet its primary functions.
skipping to change at page 18, line 46 skipping to change at page 19, line 12
[1] ITU-T Recommendation G.7710/Y.1701, "Common equipment [1] ITU-T Recommendation G.7710/Y.1701, "Common equipment
management function requirements", July, 2007. management function requirements", July, 2007.
[2] Nadeau, T., et al, "Operations and Management (OAM) [2] Nadeau, T., et al, "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS) Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006. Networks", RFC 4377, February 2006.
[3] Vigoureux, M., et al, "Requirements for OAM in MPLS [3] Vigoureux, M., et al, "Requirements for OAM in MPLS
Transport Networks", work in progress. Transport Networks", work in progress.
[4] Handley, M., et al, "Internet Denial-of-Service [4] Jones, G., "Operational Security Requirements for Large
Considerations", RFC 4732, November 2006.
[5] Jones, G., "Operational Security Requirements for Large
Internet Service Provider (ISP) IP Network Internet Service Provider (ISP) IP Network
Infrastructure", RFC 3871, September 2004. Infrastructure", RFC 3871, September 2004.
[6] Bradner, S., "Key words for use in RFCs to Indicate [5] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997. Requirement Levels", RFC 2119, March 1997.
[7] ITU-T Recommendation G.7712/Y.1703, "Architecture and [6] ITU-T Recommendation G.7712/Y.1703, "Architecture and
Specification of Data Communication Network", June 2008. specification of data communication network", June 2008.
[8] ITU-T Recommendation G.8601, "Architecture of service
management in multi bearer, multi carrier environment",
June 2006.
[9] Lam, H., et al, "Alarm Reporting Control Management
Information Base (MIB)", RFC 3878, September 2004.
[10] Bocci, M., et al, "MPLS Generic Associated Channel", RFC
5586, June 2009.
[11] Beller, D., et al, "An Inband Data Communication Network [7] Beller, D., et al, "An Inband Data Communication Network
For the MPLS Transport Profile", draft-ietf-mpls-tp-gach- For the MPLS Transport Profile", draft-ietf-mpls-tp-gach-
dcn, work in progress. dcn, work in progress.
[8] Niven-Jenkins, B. et al, "MPLS-TP Requirements", draft-
ietf-mpls-tp-requirements, work in progress.
12.2. Informative References 12.2. Informative References
[12] Chisholm, S. and D. Romascanu, "Alarm Management [9] Chisholm, S. and D. Romascanu, "Alarm Management
Information Base (MIB)", RFC 3877, September 2004. Information Base (MIB)", RFC 3877, September 2004.
[13] ITU-T Recommendation M.20, "Maintenance Philosophy for [10] ITU-T Recommendation M.20, "Maintenance philosophy for
Telecommunication Networks", October 1992. telecommunication networks", October 1992.
[14] Telcordia, "Network Maintenance: Network Element and [11] Telcordia, "Network Maintenance: Network Element and
Transport Surveillance Messages" (GR-833-CORE), Issue 5, Transport Surveillance Messages" (GR-833-CORE), Issue 5,
August 2004. August 2004.
[15] Bocci, M. et al, "A Framework for MPLS in Transport [12] Bocci, M. et al, "A Framework for MPLS in Transport
Networks", Work in Progress, November 27, 2008. Networks", draft-ietf-mpls-tp-framework, work in progress.
[16] ANSI T1.231-2003, "Layer 1 In-Service Transmission
Performance Monitoring", American National Standards
Institute, 2003.
[17] Vigoureux, M. et al, "MPLS Generic Associated Channel", [13] Bocci, M. et al, "MPLS Generic Associated Channel", RFC
draft-ietf-mpls-tp-gach-gal, work in progress. 5586, June 2009.
[18] Harrington, D., "Guidelines for Considering Operations and [14] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions", Management of New Protocols and Protocol Extensions",
draft-ietf-opsawg-operations-and-management, work in draft-ietf-opsawg-operations-and-management, work in
progress. progress.
[19] Mansfield, S. et al, "MPLS-TP Network Management [15] Mansfield, S. et al, "MPLS-TP Network Management
Framework", draft-ietf-mpls-tp-nm-framework, work in Framework", draft-ietf-mpls-tp-nm-framework, work in
progress. progress.
[20] Bocci, M. et al, "A Framework for MPLS in Transport [16] Enns, R. et al, "NETCONF Configuration Protocol", draft-
Networks", draft-ietf-mpls-tp-framework, work in progress.
[21] Enns, R. et al, "NETCONF Configuration Protocol", draft-
ietf-netconf-4741bis, work in progress. ietf-netconf-4741bis, work in progress.
[22] McCloghrie, K. et al, "Structure of Management Information [17] McCloghrie, K. et al, "Structure of Management Information
Version 2 (SMIv2)", RFC 2578, April 1999. Version 2 (SMIv2)", RFC 2578, April 1999.
[23] OMG Document formal/04-03-12, "The Common Object Request [18] OMG Document formal/04-03-12, "The Common Object Request
Broker: Architecture and Specification", Revision 3.0.3. Broker: Architecture and Specification", Revision 3.0.3.
March 12, 2004. March 12, 2004.
[24] Niven-Jenkins, B. et al, "MPLS-TP Requirements", draft- [19] Caviglia, D. et al, "Requirements for the Conversion
ietf-mpls-tp-requirements, work in progress.
[25] Caviglia, D. et al, "Requirements for the Conversion
between Permanent Connections and Switched Connections in between Permanent Connections and Switched Connections in
a Generalized Multiprotocol Label Switching (GMPLS) a Generalized Multiprotocol Label Switching (GMPLS)
Network", RFC 5493, April 2009. Network", RFC 5493, April 2009.
[26] Caviglia, D. et al, "RSVP-TE Signaling Extension For The [20] Caviglia, D. et al, "RSVP-TE Signaling Extension For The
Conversion Between Permanent Connections And Soft Conversion Between Permanent Connections And Soft
Permanent Connections In A GMPLS Enabled Transport Permanent Connections In A GMPLS Enabled Transport
Network", draft-ietf-ccamp-pc-spc-rsvpte-ext, work in Network", draft-ietf-ccamp-pc-spc-rsvpte-ext, work in
progress. progress.
[27] ITU-T Recommendation G.806, "Characteristics of transport [21] ITU-T Recommendation G.806, "Characteristics of transport
equipment - Description methodology and generic equipment - Description methodology and generic
functionality", January, 2009. functionality", January, 2009.
[28] ITU-T Recommendation Y.1731, "OAM Functions and Mechanisms [22] ITU-T Recommendation Y.1731, "OAM functions and mechanisms
for Ethernet Based Networks", February, 2008. 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., et al, "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., et al, "Internet Denial-of-Service
Considerations", RFC 4732, November 2006.
Author's Addresses Author's Addresses
Editors: Editors:
Eric Gray Eric Gray
Ericsson Ericsson
900 Chelmsford Street 900 Chelmsford Street
Lowell, MA, 01851 Lowell, MA, 01851
Phone: +1 978 275 7470 Phone: +1 978 275 7470
skipping to change at page 23, line 5 skipping to change at page 23, line 5
publication of this document (http://trustee.ietf.org/license- publication of this document (http://trustee.ietf.org/license-
info). Please review these documents carefully, as they info). Please review these documents carefully, as they
describe your rights and restrictions with respect to this describe your rights and restrictions with respect to this
document. document.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
APPENDIX A: Communication Channel (CCh) Examples Appendix A- Communication Channel (CCh) Examples
A CCh may be realized in a number of ways. A CCh may be realized in a number of ways.
1. The CCh may be provided by a link in a physically distinct 1. The CCh may be provided by a link in a physically distinct
network. That is, a link that is not part of the transport network. That is, a link that is not part of the transport
network that is being managed. For example, the nodes in the network that is being managed. For example, the nodes in the
transport network may be interconnected in two distinct physical transport network may be interconnected in two distinct physical
networks: the transport network and the DCN. networks: the transport network and the DCN.
This is a "physically distinct out-of-band CCh". This is a "physically distinct out-of-band CCh".
2. The CCh may be provided by a link in the transport network 2. The CCh may be provided by a link in the transport network
that is terminated at the ends of the DCC and which is capable that is terminated at the ends of the DCC and which is capable
of encapsulating and terminating packets of the management of encapsulating and terminating packets of the management
protocols. For example, in MPLS-TP an single-hop LSP might be protocols. For example, in MPLS-TP a single-hop LSP might be
established between two adjacent nodes, and that LSP might be established between two adjacent nodes, and that LSP might be
capable of carrying IP traffic. Management traffic can then be capable of carrying IP traffic. Management traffic can then be
inserted into the link in an LSP parallel to the LSPs that carry inserted into the link in an LSP parallel to the LSPs that carry
user traffic. user traffic.
This is a "physically shared out-of-band CCh." This is a "physically shared out-of-band CCh."
3. The CCh may be supported as its native protocol on the 3. The CCh may be supported as its native protocol on the
interface alongside the transported traffic. For example, if an interface alongside the transported traffic. For example, if an
interface is capable of sending and receiving both MPLS-TP and interface is capable of sending and receiving both MPLS-TP and
skipping to change at page 23, line 50 skipping to change at page 23, line 50
bytes does not reduce the capacity of the associated data bytes does not reduce the capacity of the associated data
channel. channel.
This is an "overhead-based CCh". This is an "overhead-based CCh".
This alternative is not available in MPLS-TP because there is no This alternative is not available in MPLS-TP because there is no
overhead available. overhead available.
5. The CCh may provided by a dedicated channel associated with 5. The CCh may provided by a dedicated channel associated with
the data link. For example, the generic associated label (GAL) the data link. For example, the generic associated label (GAL)
[17] may be used to label DCC traffic being exchanged on a data [13] may be used to label DCC traffic being exchanged on a data
link between adjacent transport nodes, potentially in the link between adjacent transport nodes, potentially in the
absence of any data LSP between those nodes. absence of any data LSP between those nodes.
This is a "data link associated CCh". This is a "data link associated CCh".
It is very similar to case 2, and by its nature can only span a It is very similar to case 2, and by its nature can only span a
single hop in the transport network. single hop in the transport network.
6. The CCh may be provided by a dedicated channel associated 6. The CCh may be provided by a dedicated channel associated
with a data channel. For example, in MPLS-TP the GAL [17] may be with a data channel. For example, in MPLS-TP the GAL [13] may be
imposed under the top label in the label stack for an MPLS-TP imposed under the top label in the label stack for an MPLS-TP
LSP to create a channel associated with the LSP that may carry LSP to create a channel associated with the LSP that may carry
management traffic. This CCh requires the receiver to be capable management traffic. This CCh requires the receiver to be capable
of demultiplexing management traffic from user traffic carried of demultiplexing management traffic from user traffic carried
on the same LSP by use of the GAL. on the same LSP by use of the GAL.
This is a "data channel associated CCh". This is a "data channel associated CCh".
7. The CCh may be provided by mixing the management traffic with 7. The CCh may be provided by mixing the management traffic with
the user traffic such that is indistinguishable on the link the user traffic such that is indistinguishable on the link
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signaling protocol traffic while others carry routing protocol signaling protocol traffic while others carry routing protocol
traffic. traffic.
It should be noted that the DCN may be a routed network with It should be noted that the DCN may be a routed network with
forwarding capabilities, but that this is not a requirement. The forwarding capabilities, but that this is not a requirement. The
ability to support forwarding of management or control traffic ability to support forwarding of management or control traffic
within the DCN may substantially simplify the topology of the within the DCN may substantially simplify the topology of the
DCN and improve its resilience, but does increase the complexity DCN and improve its resilience, but does increase the complexity
of operating the DCN. of operating the DCN.
See also RFC 3877 [12], ITU-T M.20 [13], and Telcordia document See also RFC 3877 [9], ITU-T M.20 [10], and Telcordia document
GR-833-CORE [14] for further information. GR-833-CORE [11] for further information.
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