Network Working Group Hing-Kam Lam
Internet Draft Alcatel-Lucent
Expires: October, 2009 Scott Mansfield
Intended Status: Informational Eric Gray
Ericsson
April 23, 2009
MPLS TP Network Management Framework
draft-mansfield-mpls-tp-nm-framework-01.txt
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Abstract
This document provides the network management framework the
Transport Profile for Multi-Protocol Label Switching (MPLS-TP).
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Table of Contents
1. Introduction................................................4
1.1. Terminology............................................4
2. Management Architecture Consideration.......................5
2.1. Network Management Architecture........................6
2.2. Element Management Architecture........................7
2.3. Standard Management Interfaces........................10
2.4. Management and Control specific terminology...........11
2.5. Management Channel....................................11
3. Fault Management Considerations............................13
3.1. Supervision...........................................13
3.2. Validation............................................13
3.3. Alarm Handling........................................13
4. Configuration Management Considerations....................13
4.1. LSP ownership handover................................13
5. Performance Management Considerations......................14
6. Security Considerations....................................15
7. IANA Considerations........................................15
8. Acknowledgments............................................15
9. References.................................................15
9.1. Normative References..................................15
9.2. Informative References................................16
10. Author's Addresses........................................16
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1. Introduction
This document provides a framework for using the MPLS-TP NM
requirements [1] for managing the elements and networks that
support a Transport Profile for MPLS.
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 [3].
Communication Channel (CC): a logical channel between network
elements (NEs) that can be used - e.g. - management plane
applications or control plane applications. The physical channel
supporting the CC is technology specific. An example of physical
channels supporting the CC is a DCC channel within SDH.
Data Communication Network (DCN): a network that supports Layer
1 (physical), Layer 2 (data-link), and Layer 3 (network)
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.).
Equipment Management Function (EMF): the management functions
within an NE. See ITU-T G.7710 [2].
Local Craft Terminal (LCT): An out-of-band device that connects
to an NE for management purposes.
Management Application Function (MAF): An application process
that participates in system management. See ITU-T G.7710 [2].
Management Communication Channel (MCC): a CC dedicated for
management plane communications.
Message Communication Function (MCF): The communications process
that performs functions such as information interchange and
relay. See ITU-T M.3013 [10].
Management Communication Network (MCN): A DCN supporting
management plane communication is referred to as a Management
Communication Network (MCN).
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MPLS-TP NE: a network element (NE) that supports MPLS-TP
functions.
MPLS-TP network: a network in which MPLS-TP NEs are deployed.
Network Element Function (NEF): The set of functions necessary
to manage a network element.
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 Network (SCN): A DCN supporting control
plane communication is referred to as a Signaling Communication
Network (SCN).
Signaling Communication Channel (SCC): a CC dedicated for
control plane communications. The SCC may be used for GMPLS/ASON
signaling and/or other control plane messages (e.g., routing
messages).
2. Management Architecture Consideration
The management of the MPLS-TP network could be based on a multi-
tiered distributed management systems, for example as described
in ITU-T M.3010 [7] and M.3060 [8]. Each tier provides a
predefined level of network management capabilities. The lowest
tier of this organization model includes the MPLS-TP Network
Element that provides the transport service and the Operations
System (OS) at the Element Management Level. The management
application function within the NEs and OSs provides the
management support. The management application function at each
entity can include agents only, managers only, or both agents
and managers. The management application function that include
managers are capable of managing an agent included in other
management application functions.
The management communication to peer NEs and/or Operations
System (OSs) is provided via the message communication function
within each entity (e.g. NE and OS). The user can access the
management of the MPLS-TP transport network via a Local Craft
Terminal (LCT) attached to the NE or via a Work Station (WS)
attached to the OS.
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2.1.Network Management Architecture
A transport Management Network (MN) MAY consist of several
transport technology specific Management Networks. Figure 1
below from G.7710 [2] shows an example of management network
partitioning. Notation used in G.7710 for a transport
technology specific MN is x.MN, where x is the transport
specific technology. In the example "O.MSN" is equivalent to an
optical management subnetwork, and "S.MSN" is equivalent to an
SDH management subnetwork. A MPLS-TP specific MN might be
abbreviated as MPLS-TP.MN. Where there is no ambiguity, we will
use "MN" for an MPLS-TP specific MN, and "MPLS-TP.MN" (or "MPLS-
TP MN") and "MN" where both are used in a given context.
______________________________ ______________________________
|.-------.-------.----.-------.||.-------.-------.----.-------.|
|: : : : :||: : : : :|
|:O.MSN-1:O.MSN-2: .. :O.MSN-n:||:S.MSN-1:S.MSN-2: .. :S.MSN-n:|
|: : : : :||: : : : :|
'-============================-''-============================-'
_______________________________
|.-------.-------.-----.-------.|
|: : : : :|
|:x.MSN-1:x.MSN-2: ... :x.MSN-n:|
|: : : : :|
'-=============================-'
Figure 1 Management Network Partitioning
The management of the MPLS-TP network is be separable from the
management of the other technology-specific networks, and
operate independently of any particular client or server layer
management plane.
A MPLS-TP Management Network could be partitioned into MPLS-TP
Management SubNetworks ("MPLS-TP.MSN" or "MPLS-TP MSN", or just
"MSN" where usage is unambiguous) for consideration of
scalability (e.g. geographic or load balancing) or
administrative (e.g. administrative or ownership).
The MPLS-TP MSN could be connected to other parts of the MN
through one or more LCTs and/or OSs. The message communication
function (MCF) of an MPLS-TP NE initiates/terminates, routes, or
otherwise processes management messages over CCs or via an
external interface.
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Multiple addressable MPLS-TP NEs could be present at a single
physical location (i.e. site or office). The inter-site
communications link between the MPLS-TP NEs will normally be
provided by the CCs. Within a particular site, the NEs could
communicate via an intra-site CC or via a LAN.
2.2. Element Management Architecture
The Equipment Management Function (EMF) of a MPLS-TP NE provides
the means through which a management system manages the NE.
The EMF interacts with the NE's transport functions and control
functions (i.e., control plane functions that reside in the NE)
by exchanging Management Information (MI) across the Management
Point (MP) Reference Points. The EMF may contain a number of
functions that provide a data reduction mechanism on the
information received across the MP Reference Points.
The EMF includes functions such as Date & Time and the FCAPS
(Fault, Configuration, Accounting, Performance and Security)
management functions. The EMF provides event message
processing, data storage and logging. The management Agent, a
component of the EMF, converts internal management information
(MI signals) into Management Application messages and vice
versa. The Agent responds to Management Application messages
from the message communication function by performing the
appropriate operations on (for example) the Managed Objects in a
Management Information Base (MIB), as necessary. The message
communication function contains communications functions related
to the outside world of the NE (i.e. Date & Time source,
Management Plane, Control Plane, Local Craft Terminal and Local
Alarms).
The Date & Time functions keep track of the NE's date/time which
is used by the FCAPS management functions to e.g. time stamp
event reports.
Below are diagrams that illustrate the components of the element
management function of a network element. Figure 2 provides the
breakdown of the Network Element Function, then Figure 3
provides the details of Equipment Management Function, and
finally Figure 4 details the Message Communication Function.
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___________________________________________________
| Network Element Function (NEF) |
| _________________________ _______________________ |
|| Equipment Control || Transport Plane ||
|| Function || Atomic Function ||
||_________________________||_______________________||
| | |___________| | |
| | Management Control Management | |
| | Information Information Information | |
| |__ ____________| |
| ____|____________________________|___ |
| | (from date/time)<-----------+ |
| | Equipment | | |
| | Management (to/from management)<--------+ | |
| | Function | | | |
| | (EMF) (to/from control)<-----+ | | |
| | | | | | |
| | (to local alarm)---+ | | | |
| |_____________________________________| | | | | |
| | | | | |
| +--------------------------------------+ | | | |
| | +---------------------------------------+ | | |
| | | +----------------------------------------+ | |
| | | | +-----------------------------------------+ |
| | | | | Date & Time _________________ |external
| | | | | Info | Message | |time
| | | | +-------------- Communication <-----------------------
| | | | | Function (MCF) | |
| | | | Management | | |management
| | | +----------------> | |element
| | | Plane Info | <---------------------->
| | | | | |
| | | Control Plane | | |
| | +------------------> | |
| | Information | | |control
| | | | |element
| | Local Alarm | <---------------------->
| +--------------------> | |
| Information | | |to local
| | | |alarms
| |_________________--------------------->
|____________________________________________________|
Figure 2 High-level decomposition of NEF
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_______________________________________
| ________________________ |
| Equipment | Management Application ||
| Management | Function (MAF) ||
| Function | _____ ||
| (EMF) || | _______________||
| ___________||___ | | ||
| | | | | Date & Time ||
| | Date & Time | | | Interface |<-- 1
| | Functions | | |_______________||
| |________________| | _______________||
| ___________||___ | | ||
| | | | | Management ||
| |Fault Management| | | Plane |<-> 2
| |________________| | | Interface ||
| ___________||___ | |_______________||
| | | | _______________ |
| | Configuration | | | ||
| | Management | | | Control Plane ||
| |________________| | | Interface |<-> 3
| ___________||___ | |_______________||
| | | | |
| | Account | | |
| | Management | | |
| |________________| | |
| ___________||___ | |
| | | | |
| | Performance | | |
| | Management | | |
| |________________| | |
| ___________||___ | |
| | | | |
| | Security | | |
| | Management | | _______________ |
| |________________| | | ||
| || | | Local Alarm ||
| +----->|Agent| | Interface |--> 4
| v ||_____| |_______________||
| .-===-. |_________________________|
| | MIB | |
| `-._.-' |
|_______________________________________|
Figure 3 Equipment Management Function
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_________________
| |
| Message |
| Communication |
| Function (MCF) |
| _______________ |
Date & Time || || external
1 <--------------| Date & Time <-----------------
Information || Communication || time source
||_______________||
| |
| _______________ |
Management || || management
Plane || Management || element
2 <---------------> Plane <--------------->
Information || Communication || (e.g. - EMS,
||_______________|| peer NE)
| |
| _______________ | control
Control Plane || || element
3 <---------------> Control Plane <--------------->
Information || Communication || (e.g. - EMS,
||_______________|| peer NE)
| : |
| : |
| : |
| _______________ |
Local Alarm || || to local
4 ----------------> Local Alarm |--------------->
Information || Communication || alarms...
||_______________||
|_________________|
Figure 4 Message Communication Function
2.3.Standard Management Interfaces
The MPLS-TP NM requirement document [1] places no restriction
on which management interface is to be used for managing an
MPLS-TP network. It is possible to provision and manage an
end-to-end connection across a network where some segments are
created/managed/deleted, for example by netconf/XML or snmp/smi
and other segments by CORBA/IDL interfaces. Use of any network
management interface for one management related purpose does
not preclude use of another network management interface for
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other management related purposes, or the same purpose at
another time. However, an MPLS-TP NE is not expected to
actively support more than one management protocol in any given
deployment. The protocol to be supported is at the discretion
of the operator.
2.4. Management and Control specific terminology
Data Communication Network (DCN) is the common term for the network
used to transport Management and Signaling information between:
management systems and network elements, management systems to other
management systems, and networks elements to other network elements.
The Management Communications Network (MCN) is the part of the DCN
which supports the transport of Management information for the
Management Plane. The Signaling Communications Network (SCN) is the
part of the DCN which supports transport for signaling information
for the Control Plane. As shown in Figure 5 each technology has its
own terminology that is used for the channels that support management
and control plane information transfer. For MPLS-TP, the management
plane uses the Management Communication Channel (MCC) and the control
plane uses the Signaling Communication Channel (SCC).
2.5. Management Channel
The Communication Channel (CC) provides a logical channel
between NEs for transferring Management and/or Signaling
information. Note that some technologies provide separate
communication channels for Management (MCC) and Signaling (SCC).
. MPLS-TP NEs communicate via the DCN. The DCN connects NEs
with management systems, NEs with NEs, and management
systems with management systems.
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Common Terminology |----|
/-> | NE |\
|----------| |----------| / |----| \ |----|
| | <---> | | |(CC) | NE |
|----------| |----------| \ |----| / |----|
Management Operations \-> | NE |/
Station System |----|
Network Elements use a
Communication Channel (CC)
for Transport of Management
Information
Management Terminology |----|
/-> | NE |\
|----------| |----------| / |----| \ |----|
| | <---> | | |(MCC) | NE |
|----------| |----------| \ |----| / |----|
Management Operations \-> | NE |/
Station System |----|
Network Elements use a
Management Communication
Channel (MCC) for Transport
of Management Information
Control Terminology |----|
/-> | NE |\
|----------| |----------| / |----| \ |----|
| | <---> | | |(SCC) | NE |
|----------| |----------| \ |----| / |----|
Management Operations \-> | NE |/
Station System |----|
Network Elements use a
Control/Signaling Communication
Channel (SCC) for Transport
of Signaling Information
Figure 5 Communication Channel Terminology
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3. Fault Management Considerations
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. Fault management
provides the mechanisms to detect, verify, isolate, notify, and
recover from the fault.
3.1. Supervision
G.7710 [2] lists five basic categories of supervision that provide
the functionality necessary to detect, verify, and notify a fault.
The categories are: Transmission Supervision, Quality of Service
Supervision, Processing Supervision, Hardware Supervision, and
Environment Supervision. Each of the categories provides a set of
recommendations to ensure the fault management process is fulfilled.
3.2. Validation
G.7710 [2] describes a fault cause as a limited interruption of the
required function. It is not reasonable for every fault cause to be
reported to maintenance personnel. The validation process is used to
turn fault causes (events) into failures (alarms).
3.3. Alarm Handling
Within an element management system, it is important to consider
mechanisms to support severity assignment, alarm reporting control,
and logging.
4. Configuration Management Considerations
Configuration management provides the mechanisms to provision the
MPLS-TP services, setup security for the MPLS-TP services and MPLS-TP
network elements, and provides the destination for fault
notifications and performance parameters. Inventory reporting is
also considered part of configuration management.
Associated with configuration management are hardware and software
provisioning and inventory reporting.
4.1. LSP ownership handover
MPLS-TP networks can be managed not only by Network Management
Systems (i.e. management plane), but also by control plane protocols.
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The utilization of the control plane is not a mandatory requirement
(see MPLS-TP Requirements [4]) but it is often used by network
operators in order to make network configuration and LSP recovery
both faster and simpler.
In networks where both CP and MP are provided, an LSP could be
created by either (CP or MP). The entity creating an LSP owns the
data plane resources comprising that LSP. Only the owner of an LSP
is typically able modify/delete it. This results in a need for
interaction between the MP and CP to allow either to manage all the
resources of a network.
Network operators might prefer to have full control of the network
resources during the set-up phase and then allow the network to be
automatically maintained by the control plane. This can be achieved
by creating LSPs via the management plane and subsequently
transferring LSP ownership to the control plane. This is referred to
as "ownership handover" [9]. MP to CP ownership handover is then
considered a requirement [9] where a control plane is in use that
supports it. The converse (CP to MP ownership handover) is a feature
that is recommended - but not required - for (G)MPLS networks because
it has only minor applications (for example moving LSPs from one path
to another as a maintenance operation).
The LSP handover procedure has already been standardized for GMPLS
networks, where the signaling protocol used is RSVP-TE [5]. The
utilization of RSVP-TE enhancements are defined in [6].
MP and CP interworking includes also the exchange of information that
is either requested by the MP, or a notification by the CP as a
consequence of a request from the MP or an automatic action (for
example a failure occurs or an operation is performed). The CP is
asked to notify the MP in a reliable manner about the status of the
operations it performs and to provide a mechanism to monitor the
status of control plane objects (e.g. TE Link status, available
resources), and to log control plane LSP related operations. Logging
is one of the most critical aspects because the MP always needs to
have an accurate history and status of each LSP and all data plane
resources involved in it.
5. Performance Management Considerations
Performance statistics can overwhelm a management network, so it is
important to provide flexible instrumentation that provides control
over the amount of performance data to be collected. A distinction
is made between performance data that is collected on-demand and data
that is collected proactively. On-demand measurement provides the
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operator the ability to issue a command to initiate a measurement.
Proactive measurement is something that happens continuously over
time after being configured with a periodicity and storage
requirements. Data collected from proactive measurement are usually
used for verifying the performance of the LSP service, while data
collected from on-demand measurement are usually used for maintenance
purposes such as diagnose or to provide detailed verification of
proactive measurement.
6. Security Considerations
Provisions to any of the network mechanisms designed to satisfy
the requirements described herein are required to prevent their
unauthorized use. Likewise, these network mechanisms MUST
provide a means by which an operator can prevent denial of
service attacks if those network mechanisms are used in such an
attack.
Solutions MUST provide mechanisms to prevent private
information from being accessed by unauthorized eavesdropping,
or being directly obtained by an unauthenticated network
element, system or user.
Performance of diagnostic functions and path characterization
involves extracting a significant amount of information about
network construction that the network operator MAY consider
private.
7. IANA Considerations
There are no IANA actions associated with this document.
8. Acknowledgments
The authors/editors gratefully acknowledge the thoughtful review,
comments and explanations provided by Diego Caviglia and Bernd
Zeuner.
9. References
9.1. Normative References
[1] Lam, H.K., et al., "MPLS TP Network Management
Requirements", work in progress.
[2] ITU-T Recommendation G.7710/Y.1701, "Common equipment
management function requirements", July, 2007.
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[3] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[4] Niven-Jenkins, B., et al., "MPLS-TP Requirements", work in
progress.
[5] Awduche, D., et al., "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[6] Caviglia, D., et al., "RSVP-TE Signaling Extension For The
Conversion Between Permanent Connections And Soft
Permanent Connections In A GMPLS Enabled Transport
Network", work in progress.
9.2.Informative References
[7] ITU-T Recommendation M.3010, "Principles for a
telecommunication management network", April 2005.
[8] ITU-T Recommendation M.3060/Y.2401, "Principles for the
Management of Next Generation Networks", March 2006.
[9] 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.
[10] ITU-T Recommendation M.3013, "Considerations for a
telecommunications management network", February 2000.
10.Author's Addresses
Editors:
Scott Mansfield
Ericsson
5000 Ericsson Drive
Warrendale, PA, 15086
Phone: +1 724 742 6726
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
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Eric Gray
Ericsson
900 Chelmsford Street
Lowell, MA, 01851
Phone: +1 978 275 7470
Email: eric.gray@ericsson.com
Author(s):
Contributor(s):
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