Network Working Group Hing-Kam Lam
Internet Draft Alcatel-Lucent
Expires: March 18, 2010 Scott Mansfield
Intended Status: Standards Track Eric Gray
Ericsson
September 18, 2009
MPLS TP Network Management Requirements
draft-ietf-mpls-tp-nm-req-05.txt
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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.
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Table of Contents
1. Introduction..............................................3
1.1. Terminology..........................................4
2. Management Interface Requirements.........................6
3. Management Communication Channel (MCC) Requirements.......6
4. Management Communication Network (MCN) Requirements.......6
5. Fault Management Requirements.............................8
5.1. Supervision Function.................................8
5.2. Validation Function..................................9
5.3. Alarm Handling Function.............................10
5.3.1. Alarm Severity Assignment......................10
5.3.2. Alarm Suppression .............................10
5.3.3. Alarm Reporting................................11
5.3.4. Alarm Reporting Control........................11
6. Configuration Management Requirements....................11
6.1. System Configuration................................12
6.2. Control Plane Configuration.........................12
6.3. Path Configuration..................................12
6.4. Protection Configuration............................13
6.5. OAM Configuration...................................13
7. Performance Management Requirements......................14
7.1. Path Characterization Performance Metrics...........14
7.2. Performance Measurement Instrumentation.............16
7.2.1. Measurement Frequency..........................16
7.2.2. Measurement Scope .............................16
8. Security Management Requirements.........................16
8.1. Management Communication Channel Security...........17
8.2. Signaling Communication Channel Security............17
8.3. Distributed Denial of Service ......................17
9. Security Considerations..................................18
10. IANA Considerations.....................................18
11. Acknowledgments.........................................18
12. References..............................................18
12.1. Normative References...............................18
12.2. Informative References.............................19
Author's Addresses..........................................21
Copyright Statement.........................................21
Acknowledgment..............................................22
Appendix A - Communication Channel (CCh) Examples...........23
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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 best common practice as defined in [14].
ITU-T G.7710/Y.1701 defines generic management requirements for
transport networks. RFC 4377 specifies the OAM requirements,
including OAM-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 PWE3 architectures to support capabilities and functionality
of a transport network as defined by ITU-T.
The requirements in this document derive from two sources:
1) MPLS and PWE3 architectures as defined by IETF, and
2) packet transport networks as defined by 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 [1] and [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 references [12] and [15].
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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 which 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], 3.7).
Communication Channel (CCh): A logical channel between network
elements (NEs) that can be used - e.g. - 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], 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], 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], 3.26).
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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 which is intended to identify the defect
that is representative of the disturbance or fault that is
causing the problem (from [21], 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 [7] for further information on functionality
required to support MPLS-TP.
MPLS-TP network: a network in which MPLS-TP NEs are deployed.
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 - for example - in
Y.1731 ([22] - 3.45 and 3.44 respectively) as:
. On-demand OAM - OAM actions which 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.
. Proactive OAM - OAM actions which 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.
Signaling Communication Channel (SCC): A CCh dedicated for
control plane communications. The SCC may be used for GMPLS/ASON
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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 which management interface
protocol should 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/XML ([16]) or SNMP/SMI ([17]), and another
domain via CORBA/IDL ([18]), is allowed.
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 MPLS-TP NE may use one
protocol for configuration and another for monitoring. The
protocols to be supported are at the discretion of the operator.
3. Management Communication Channel (MCC) Requirements
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.
For management purpose, 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.
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RFC 5586 [13] 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. Reference [8]
describes how the G-ACh may 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).
ITU-T G.7712/Y.1703 [6], section 7, describes the transport DCN
architecture and requirements. The MPLS-TP MCN MUST support the
requirements (in reference [6]) for:
- CCh access functions specified in section 7.1.1;
- MPLS-TP SCC data-link layer termination functions specified
in section 7.1.2.3;
- MPLS-TP MCC data-link layer termination functions specified
in section 7.1.2.4;
- Network layer PDU into CCh data-link frame encapsulation
functions specified in section 7.1.3;
- Network layer PDU forwarding (7.1.6), interworking (7.1.7)
and encapsulation (7.1.8) functions, as well as tunneling
(7.1.9) and routing (7.1.10) functions specified in [6].
As a practical matter, MCN connections will typically have
addresses. See the section on addressing in [15] for further
information.
In order to have the MCN operate properly, a number of
management functions for the MCN are needed, including:
. Retrieval of DCN network parameters to ensure compatible
functioning, e.g. packet size, timeouts, quality of
service, window size, etc.;
. Establishment of message routing between DCN nodes;
. Management of DCN network addresses;
. Retrieval of operational status of the DCN at a given node;
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. Capability to enable/disable access by an NE to the DCN.
Note that this is to allow isolating a malfunctioning NE
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 analyses 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.
The MPLS-TP NE MUST support supervision of the OAM mechanisms
that are deployed for supporting the OAM requirements defined in
[1].
The MPLS-TP NE MUST support the following data-plane forwarding
path supervision functions:
. 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);
. Supervision of failure detection;
The MPLS-TP NE MUST support the capability to configure data-
plane forwarding path related supervision mechanisms to perform
on-demand or proactively.
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.
The MPLS-TP NE MUST support hardware-related supervision for
interchangeable and non-interchangeable unit, cable, and power
problems.
The MPLS-TP NE SHOULD support environment-related supervision
for temperature, humidity, etc.
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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 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.
The MPLS-TP NE MUST perform persistency checks on fault causes
before it declares a fault cause a failure.
The MPLS-TP NE SHOULD provide a configuration capability for
control parameters associated with performing the persistency
checks described above.
An MPLS-TP NE MAY provide configuration parameters to control
reporting, and clearing, of failure conditions.
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].
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
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specifications SHOULD define the level of granularity at which
tables of these values are to be defined.
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.
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.
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.
5.3.2. Alarm Suppression
Alarms can be generated from many sources, including OAM, device
status, etc.
An MPLS-TP NE MUST support suppression of alarms based on
configuration.
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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.
An MPLS-TP NE MUST support local reporting of alarms.
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.
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 an 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 (e.g., LSP) basis 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.
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).
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6.1. System Configuration
The MPLS-TP NE MUST support the configuration requirements
specified in G.7710 [1] section 8.1 for hardware.
The MPLS-TP NE MUST support the configuration requirements
specified in G.7710 [1] section 8.2 for software.
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.
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.
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
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
In addition to the requirement to support static provisioning of
transport paths (defined in [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).
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.
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
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hand-off of Path control. See, for example, references [19] and
[20].
Further detailed requirements will be provided along with
progress in defining the MPLS-TP control plane in appropriate
specifications.
If MPLS-TP transport paths cannot be statically provisioned
using MPLS LSP and pseudo-wire management tools (either already
defined in standards or under development), further management
specifications MUST be provided as needed.
6.4. Protection Configuration
The MPLS-TP NE MUST support configuration of required path
protection information as follows:
. designate specifically identified LSPs as working or
protecting LSPs;
. define associations of working and protecting paths;
. operate/release manual protection switching;
. operate/release force protection switching;
. operate/release protection lockout;
. set/retrieve Automatic Protection Switching (APS)
parameters, including -
o Wait to Restore time,
o Protection Switching threshold information.
6.5. OAM Configuration
The MPLS-TP NE MUST support configuration of the OAM entities
and functions specified in [3].
The MPLS-TP NE MUST support the capability to choose which OAM
functions are enabled.
For enabled OAM functions, the MPLS-TP NE MUST support the
ability to associate OAM functions with specific maintenance
entities.
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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.
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.
The MPLS-TP NE MUST support configuration of OAM parameters to
meet their specific operational requirements, such as whether -
1) one-time on-demand immediately or
2) one-time on-demand pre-scheduled or
3) on-demand periodically based on a specified schedule or
4) proactive on-going.
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 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
It MUST be possible to determine when an MPLS-TP based transport
service is available and when it is unavailable.
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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.
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.
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 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)
statistics.
The MPLS-TP NE MUST support collection of delay measurement (DM)
statistics.
The MPLS-TP NE MUST support reporting of Performance degradation
via fault management for corrective actions. "Reporting" in this
context could mean:
. reporting to an autonomous protection component to trigger
protection switching,
. reporting via a craft interface to allow replacement of a
faulty component (or similar manual intervention),
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. etc.
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
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.
7.2.2. Measurement Scope
On measurement of packet loss and loss ratio:
. For bidirectional (both co-routed and associated) P2P
connections:
o on-demand measurement of single-ended packet loss, and
loss ratio, measurement is REQUIRED;
o proactive measurement of packet loss, and loss ratio,
measurement for each direction is REQUIRED.
. for unidirectional (P2P and P2MP) connection, proactive
measurement of packet loss, and loss ratio, is REQUIRED.
On Delay measurement:
. for unidirectional (P2P and P2MP) connection, on-demand
measurement of delay measurement is REQUIRED.
. for co-routed bidirectional (P2P) connection, on-demand
measurement of one-way and two-way delay is REQUIRED.
. for associated bidirectional (P2P) connection, on-demand
measurement of one-way delay is REQUIRED.
8. Security Management Requirements
The MPLS-TP NE MUST support secure management and control
planes.
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8.1. Management Communication Channel Security
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. The MCC MUST support application
protocols that provide confidentiality and data integrity
protection.
The MPLS-TP NE MUST support the following:
- Use of open cryptographic algorithms (See RFC 3871 [4])
- Authentication - allow management connectivity only from
authenticated entities.
- Authorization - allow management activity originated by an
authorized entity, using (for example) an Access Control
List (ACL).
- 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.
Management of control plane security MUST also be defined at
that time.
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
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ingress filtering. RFC 4732 [26] provides background on DOS in
the context of the Internet.
An MPLS-TP NE MUST support secure management protocols and
SHOULD do so in a manner the reduce potential impact of a DoS
attack.
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.
9. Security Considerations
Section 8 includes a set of security requirements that apply to
MPLS-TP network management.
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. IANA Considerations
There are no IANA actions associated with this document.
11. 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.
12. References
12.1. Normative References
[1] ITU-T Recommendation G.7710/Y.1701, "Common equipment
management function requirements", July, 2007.
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[2] Nadeau, T., et al, "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006.
[3] Vigoureux, M., et al, "Requirements for OAM in MPLS
Transport Networks", draft-ietf-mpls-tp-oam-requirements,
work in progress.
[4] Jones, G., "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", RFC 2119, March 1997.
[6] ITU-T Recommendation G.7712/Y.1703, "Architecture and
specification of data communication network", June 2008.
[7] Niven-Jenkins, B. et al, "MPLS-TP Requirements", draft-
ietf-mpls-tp-requirements, work in progress.
12.2. Informative References
[8] Beller, D., et al, "An Inband Data Communication Network
For the MPLS Transport Profile", draft-ietf-mpls-tp-gach-
dcn, work in progress.
[9] Chisholm, S. and D. Romascanu, "Alarm Management
Information Base (MIB)", RFC 3877, September 2004.
[10] ITU-T Recommendation M.20, "Maintenance philosophy for
telecommunication networks", October 1992.
[11] Telcordia, "Network Maintenance: Network Element and
Transport Surveillance Messages" (GR-833-CORE), Issue 5,
August 2004.
[12] Bocci, M. et al, "A Framework for MPLS in Transport
Networks", draft-ietf-mpls-tp-framework, work in progress.
[13] Bocci, M. et al, "MPLS Generic Associated Channel", RFC
5586, June 2009.
[14] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions",
draft-ietf-opsawg-operations-and-management, work in
progress.
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[15] Mansfield, S. et al, "MPLS-TP Network Management
Framework", draft-ietf-mpls-tp-nm-framework, work in
progress.
[16] Enns, R. et al, "NETCONF Configuration Protocol",
draft-ietf-netconf-4741bis, work in progress.
[17] McCloghrie, K. et al, "Structure of Management Information
Version 2 (SMIv2)", RFC 2578, April 1999.
[18] OMG Document formal/04-03-12, "The Common Object Request
Broker: Architecture and Specification", Revision 3.0.3.
March 12, 2004.
[19] Caviglia, D. et al, "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. et al, "RSVP-TE Signaling Extension For The
Conversion Between Permanent Connections And Soft
Permanent Connections In A GMPLS Enabled Transport
Network", draft-ietf-ccamp-pc-spc-rsvpte-ext, work in
progress.
[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., 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.
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Editors' 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: hklam@Alcatel-Lucent.com
Contributor's Address
Adrian Farrel
Old Dog Consulting
Email: adrian@olddog.co.uk
Copyright Statement
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-
info). Please review these documents carefully, as they
describe your rights and restrictions with respect to this
document.
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Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
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Appendix A- Communication Channel (CCh) Examples
A CCh may be realized in a number of ways.
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 being managed. For example, the nodes in the
transport network may 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 may be provided by a link in the transport network
that is terminated at the ends of the CCh and which 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 may 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 may 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 may provided by a dedicated channel associated with
the data link. For example, the generic associated label (GAL)
[13] may be used to label CCh traffic being exchanged on a data
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link between adjacent transport nodes, potentially in the
absence of any data LSP between those nodes.
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 may be provided by a dedicated channel associated
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
LSP to create a channel associated with the LSP that may 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 may 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 is able to demultiplex the
management and user traffic. Such might be possible in MPLS-TP
if the MPLS-TP LSP was carrying IP user traffic.
This is an "in-band CCh".
These realizations may 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 may be
realized by the same DCN or as separate networks. In practice,
that means that, between any pair of nodes, the MCC and SCC may
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
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pair of adjacent nodes may 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 may be deployed for DCN resilience or
load sharing. Links may be designated for specific use. For
example, so that some links 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 should be noted that the DCN may 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 may substantially simplify the topology of the
DCN and improve its resilience, but does increase the complexity
of operating the DCN.
See also RFC 3877 [9], ITU-T M.20 [10], and Telcordia document
GR-833-CORE [11] for further information.
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