Network Working Group D. King (Editor)
Internet-Draft Old Dog Consulting
Intended status: Informational M. Venkatesan (Editor)
Expires: June 5, 2011 Aricent
January 5, 2011
Multiprotocol Label Switching Transport Profile (MPLS-TP)
MIB-based Management Overview
draft-ietf-mpls-tp-mib-management-overview-01.txt
Abstract
A range of Management Information Base (MIB) modules has been
developed to help model and manage the various aspects of
Multiprotocol Label Switching (MPLS) networks. These MIB modules are
defined in separate documents that focus on the specific areas of
responsibility of the modules that they describe.
The MPLS Transport Profile (MPLS-TP) is a profile of MPLS
functionality specific to the construction of packet-switched
transport networks.
This document describes the MIB-based management architecture for
MPLS-TP, indicates the interrelationships between different
existing MIB modules that can be leveraged for MPLS-TP network
management and identifies areas where additional MIB modules would be
required.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network as
defined by the ITU-T.
This Informational Internet-Draft is aimed at achieving IETF
Consensus before publication as an RFC and will be subject to an IETF
Last Call.
[RFC Editor, please remove this note before publication as an RFC and
insert the correct Streams Boilerplate to indicate that the published
RFC has IETF Consensus.]
King & Venkatesan, et al. [Page 1]
draft-ietf-mpls-tp-mib-management-overview-01.txt January 2011
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on June 5, 2011.
Copyright Notice
Copyright (c) 2011 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
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described in the Simplified BSD License.
King & Venkatesan, et al. [Page 2]
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Table of Contents
1. Introduction.................................................4
2. Terminology..................................................4
3. The SNMP Management Framework................................4
4. Summary of MPLS-TP Management Function.......................5
5. Overview of Existing Work....................................5
5.1. MPLS Management Overview and Requirements...............5
5.2. An Introduction to the MPLS and Pseudowire MIB Modules..6
5.2.1. Structure of the MPLS MIB OID Tree...............6
5.2.2. Textual Convention Modules.......................7
5.2.3. Mapping Data to LSPs.............................7
5.2.4. Label Switching Router Modules...................8
5.2.5. Label Switched Path Modules......................8
5.2.6. Pseudowire Modules...............................8
5.2.7. Routing and Traffic Engineering..................10
5.2.8. Resiliency.......................................10
5.2.9. Fault Management and Performance Management......11
5.2.10. MIB Module Interdependencies....................12
5.2.11. Dependencies on External MIB Modules............14
6. Applicability of MPLS MIB modules to MPLS-TP.................14
6.1 Gap Analysis............................................15
6.1.1 MPLS-TP Tunnel....................................15
6.1.2 MPLS-TP Pseudowire................................15
6.1.3 MPLS-TP Sections..................................15
6.1.4 MPLS-TP OAM.......................................15
6.1.5 MPLS-TP Protection Switching......................16
7. Interfaces...................................................16
7.1. MPLS Tunnels as Interfaces..............................17
7.2. Application of the Interfaces Group to TE Links.........17
7.3. References to Interface Objects from MPLS MIB Modules...17
8. Management Options...........................................17
9. Security Considerations......................................18
10. IANA Considerations.........................................18
11. Acknowledgements............................................18
12. References..................................................18
12.1. Normative References..................................18
12.2. Informational References..............................20
14. Authors' Addresses..........................................22
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1. Introduction
The MPLS Transport Profile (MPLS-TP) is a packet transport
technology based on a profile of the MPLS functionality specific
to the construction of packet-switched transport networks.
MPLS is described in [RFC3031] and requirements for MPLS-TP are
specified in [RFC5654].
A range of Management Information Base (MIB) modules has been
developed to help model and manage the various aspects of
Multiprotocol Label Switching (MPLS) networks. These MIB modules
are defined in separate documents that focus on the specific areas of
responsibility of the modules that they describe.
An MPLS-TP network can be operated via static provisioning of
transport paths, or the elective use of a Generalized MPLS (GMPLS)
control plane to support dynamic provisioning of transport paths.
This document describes the MIB-based management architecture for
MPLS-TP and indicates the interrelationships between different
existing MIB modules that should be leveraged for MPLS-TP network
management.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network.
2. Terminology
This document also uses terminology from the MPLS architecture
document [RFC3031] and the following MPLS related MIB modules:
MPLS TC MIB [RFC3811], MPLS LSR MIB [RFC3813], MPLS TE MIB [RFC3812],
MPLS LDP MIB [RFC3815], MPLS FTN MIB [RFC3814] and TE LINK MIB
[RFC4220].
3. The SNMP Management Framework
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI).
For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].
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This document discusses MIB modules that are compliant to the SMIv2,
which is described in [RFC2578], [RFC2579] and [RFC2580].
4. Summary of MPLS-TP Management Function
The management of the MPLS-TP networks is separable from that of its
client networks so that the same means of management can be used
regardless of the client. The management functions of MPLS-TP
includes fault management, configuration management, performance
monitoring, and security management.
5. Overview of Existing Work
This section describes the existing tools and techniques for
managing and modeling MPLS networks, devices, and protocols. It does
not focus on MPLS-TP, but is intended to provide a description of the
tool kit that is already available.
The following section (Section 6. Applicability of MPLS MIB modules
to MPLS-TP) of this document outlines the existing MPLS MIB modules
and optional use of GMPLS MIB modules to MPLS-TP and examines the
additional MIB modules and objects that would be required for
managing an MPLS-TP network.
5.1. MPLS Management Overview and Requirements
[RFC4378] outlines how data plane protocols can assist in providing
the Operations and Management (OAM) requirements outlined in
[RFC4377] and how it is applied to the management functions of fault,
configuration, accounting, performance, and security (commonly known
as FCAPS) for MPLS networks.
[RFC4221] describes the management architecture for MPLS. In
particular, it describes how the managed objects defined in various
MPLS-related MIB modules model different aspects of MPLS, as well as
the interactions and dependencies between each of these MIB modules.
[RFC4377] describes the requirements for user and data plane OAM and
applications for MPLS.
[RFC5654] describes the requirements for the optional use of a
control plane to support dynamic provisioning of MPLS-TP transport
paths. The MPLS-TP LSP control plane is based on GMPLS and is
described in [RFC3945].
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5.2. An Introduction to the MPLS and Pseudowire MIB Modules
5.2.1. Structure of the MPLS MIB OID Tree
The MPLS MIB OID tree has the following structure compatible for
MPLS-TP.
mib-2 -- RFC 2578 [RFC2578]
|
+-transmission
| |
| +- mplsStdMIB
| | |
| | +- mplsTCStdMIB -- MPLS-TC-STD-MIB [RFC3811]
| | |
| | +- mplsLsrStdMIB -- MPLS-LSR-STD-MIB [RFC3813]
| | |
| | +- mplsTeStdMIB -- MPLS-TE-STD-MIB [RFC3812]
| | |
| | +- mplsLdpStdMIB -- MPLS-LDP-STD-MIB [RFC3815]
| | |
| | +- mplsLdpGenericStdMIB -- MPLS-LDP-GENERIC-STD-MIB
| | |
| | +- mplsFTNStdMIB -- MPLS-FTN-STD-MIB [RFC3814]
| | |
| | +- gmplsTCStdMIB -- GMPLS-TC-STD-MIB [RFC4801]
| | |
| | +- gmplsTeStdMIB -- GMPLS-TE-STD-MIB [RFC4802]
| | |
| | +- gmplsLsrStdMIB -- GMPLS-LSR-STD-MIB [RFC4803]
| | |
| | +- gmplsLabelStdMIB -- GMPLS-LABEL-STD-MIB [RFC4803]
| |
| +- teLinkStdMIB -- TE-LINK-STD-MIB [RFC4220]
| |
| +- pwStdMIB -- PW-STD-MIB [RFC5601]
|
+- ianaGmpls -- IANA-GMPLS-TC-MIB [RFC4802]
|
+- ianaPwe3MIB -- IANA-PWE3-MIB [RFC5601]
|
+- pwEnetStdMIB -- PW-ENET-STD-MIB [RFC5603]
|
+- pwMplsStdMIB -- PW-MPLS-STD-MIB [RFC5602]
|
+- pwTDMMIB -- PW-TDM-MIB [RFC5604]
|
+- pwTcStdMIB -- PW-TC-STD-MIB [RFC5542]
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Note: The OIDs for MIB modules are assigned and managed by IANA.
They can be found in the referenced MIB documents.
5.2.2. Textual Convention Modules
MPLS-TC-STD-MIB [RFC3811] and GMPLS-TC-STD-MIB [RFC4801] contains the
Textual Conventions for MPLS and GMPLS networks. These Textual
Conventions should be imported by MIB modules which manage MPLS
and GMPLS networks.
5.2.3. Mapping Data to LSPs
MPLS is a packet switching protocol that operates between the
Network layer and the data link layer in the OSI model.
There is a clean separation between the control and forwarding
planes in the MPLS protocol. This helps in easy portability and
extensibility to the forwarding functions.
A router which supports MPLS is known as a "Label Switching Router",
or LSR. An LSR implements the control and forwarding plane of MPLS.
The LSR "control plane" provides information in terms of label
bindings which are part of the information used to populate
forwarding tables in an LSR. An LSR determines which label bindings
to seek and retain based on configuration and other information.
The LSR forwarding plane then uses an index which is the incoming
interface and label (usually of 20-bit length) to forward the
packet.
Each entry in this forwarding table corresponds to a forwarding
equivalence class (FEC). This can be loosely defined as the set of
characteristics that are being shared by the packets which will be
forwarded in a similar fashion and may share the same label.
MPLS packets are encapsulated by one more label entries referred to
as the label stack. Each label stack entry consists of a label, the
3 TC-bits for classifying the Traffic Class, the bottom of stack bit,
and TTL.
The ingress and the egress devices of the MPLS network are called
Label Edge routers. These routers "Push" an MPLS label into an
incoming packet and "pop" off the MPLS label from an outgoing packet
respectively.
At the ingress when an unlabeled packet enters, one or more label
stack entries are (each label stack with one or more labels) is
prefixed to this packet based on its FEC as discussed above. In
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addition, the "MPLS-specific" L2 encapsulation (including, for
instance, the MPLS PID) is also added at the ingress. Then the packet
is sent to the next-hop router for further processing. The next-hop
router examines the topmost label in the label stack and then does a
swap, 'push' or 'pop' operations based on the contents.
A label stack entry can be 'popped' or removed from the top of the
label stack or a label stack entry is 'pushed' or inserted into the
top of the stack based on the FEC information.
When a 'swap' operation is executed, the topmost label stack entry is
replaced with a different one and the depth of the label stack
remains the same. After the swap the packet is forwarded based on the
new entry.
5.2.4. Label Switching Router Modules
MPLS-LSR-STD-MIB [RFC3813] describes the managed objects for modeling
a Multiprotocol Label Switching (MPLS) [RFC3031] LSR.
MPLS-TP is specific to the use of MPLS in transport networks.
According to [RFC5654] multipoint-to-point LSPs do not form part of
MPLS-TP, so multipoint-to-point cross-connects are out of scope for
this document.
5.2.5. Label Switched Path Modules
The path taken through the MPLS domain by a packet is referred to as
a label switched path (LSP). It is possible that this path may not be
understood or completely stored in one LSR within the MPLS domain.
MPLS-LSR-STD-MIB [RFC3813] defines the required objects for setting
up an LSP. It defines the conceptual object MPLS cross-connect that
is used to map incoming labels to outgoing labels on a MPLS enabled
interfaces. This is referenced by other MIB modules in order to refer
to an underlying MPLS LSP.
This label switched path can be programmed using a variety of
mechanisms. These include manual programming and using a signalling
protocol.
RSVP-TE (Resource reservation protocol for Traffic Engineering) is
normally used for signalling LSPs used for Traffic Engineering.
5.2.6. Pseudowire Modules
The PW (Pseudowire) MIB modules architecture provides a layered
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modular model into which any supported emulated service can be
connected to any supported packet switched network (PSN) type.
Emulated Service Layer, Generic PW Layer and PSN VC Layer constitute
the different layers of the model. A combination of the MIB modules
belonging to each layer provides the glue for mapping the emulated
service onto the native PSN service. At least three MIB modules each
belonging to a different layer is required to define a PW emulated
service.
Starting from the emulated Service Layer, the first is a
service-specific module that is dependent on the emulated signal
type.
The second is the PW-STD-MIB module, which configures general
parameters of the PW that are common to all types of emulated
services and PSN types.
The third is a PSN-specific module. There is a different module for
each type of PSN. These modules associate the PW with one or more
"tunnels" that carry the service over the PSN. These modules are
defined in other documents.
PW-STD-MIB [RFC5601] defines a MIB module that can be
used to manage pseudowire (PW) services for transmission over a
Packet Switched Network (PSN) [RFC3931] [RFC4447]. This MIB module
provides generic management of PWs that is common to all types of
PSN and PW services defined by the IETF PWE3 Working Group.
PW-MPLS-STD-MIB [RFC5602] describes a model for managing pseudowire
services for transmission over different flavors of MPLS tunnels.
The general PW MIB module [RFC5601] defines the parameters global to
the PW regardless of the underlying Packet Switched Network (PSN)
and emulated service. This document is applicable for PWs that use
MPLS PSN type in the PW-STD-MIB.
This document describes the MIB objects that define pseudowire
association to the MPLS PSN, in a way that is not specific to the
carried service.
Together, [RFC3811] and [RFC3812] describe the modeling of an MPLS
tunnel, and a tunnel's underlying cross-connects. This MIB module
supports MPLS-TE PSN, non-TE MPLS PSN (an outer tunnel created by the
Label Distribution Protocol (LDP) or manually), and MPLS PW label
only (no outer tunnel).
PW-ENET-STD-MIB [RFC5603] describes a model for managing Ethernet
pseudowire services for transmission over a PSN. This MIB module is
generic and common to all types of PSNs supported in the Pseudowire
Emulation Edge-to-Edge (PWE3) architecture [RFC3985], which describes
the transport and encapsulation of L1 and L2 services over supported
PSN types.
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In particular, the MIB module associates a port or specific VLANs on
top of a physical Ethernet port or a virtual Ethernet interface (for
Virtual Private LAN Service (VPLS)) to a point-to-point PW. It is
complementary to the PW-STD-MIB [RFC5601], which manages the generic
PW parameters common to all services, including all supported PSN
types.
PW-TDM-MIB [RFC5604] describes a model for managing TDM pseudowires,
i.e., TDM data encapsulated for transmission over a Packet Switched
Network (PSN). The term TDM in this document is limited to the
scope of Plesiochronous Digital Hierarchy (PDH). It is currently
specified to carry any TDM Signals in either Structure Agnostic
Transport mode (E1, T1, E3, and T3) or in Structure Aware
Transport mode (E1, T1, and NxDS0) as defined in the Pseudowire
Emulation Edge-to-Edge (PWE3) TDM Requirements document [RFC4197].
5.2.7. Routing and Traffic Engineering
In MPLS traffic engineering, its possible to specify explicit routes
or choose routes based on QOS metrics in setting up a path such that
some specific data can be routed around network hot spots.
MPLS-TE-STD-MIB [RFC3812] describes managed objects for modeling a
Multiprotocol Label Switching (MPLS) [RFC3031] based traffic
engineering. This MIB module should be used in conjunction with the
companion document [RFC3813] for MPLS based traffic engineering
configuration and management.
5.2.8. Resiliency
MPLS Fast Reroute is a local restoration network resiliency mechanism
in MPLS TE for link and node protection. Two different modes of local
protection are described in the [RFC4090] to protect LSP.
o One-to-One Backup
o Facility Backup
Facility backup uses label stacking to reroute multiple protected TE
LSPs using a single backup TE LSP. One-to-one backup does not use
label stacking, and every protected TE LSP requires a dedicated
backup TE LSP.
MPLS-FRR-GENERAL-STD-MIB [draft-ietf-mpls-fastreroute-mib-14]
contains objects that apply to any MPLS LSR implementing MPLS TE fast
reroute functionality.
MPLS-FRR-ONE2ONE-STD-MIB [draft-ietf-mpls-fastreroute-mib-14]
contains objects that apply to one-to-one backup method.
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MPLS-FRR-FACILITY-STD-MIB [draft-ietf-mpls-fastreroute-mib-14]
contains objects that apply to facility backup method.
5.2.9. Fault Management and Performance Management
MPLS manages the LSP and pseudowire faults through the use of LSP
ping [RFC4379], VCCV [RFC5085], BFD for LSPs [RFC5884] and BFD for
VCCV [RFC5885] tools.
Current MPLS focuses on the in and/or out packet counters,
errored packets, discontinuity time.
Some of the MPLS and Pseudowire performance tables used for
performance management are given below.
mplsTunnelPerfTable provides several counters (packets forwarded,
packets dropped because of errors) to measure the performance of
the MPLS tunnels.
mplsInterfacePerfTable provides performance information (incoming and
outgoing labels in use and lookup failures) on a per-interface basis.
mplsInSegmentPerfTable contains statistical information (total
packets received by the insegment, total errored packets received,
total packets discarded, discontinuity time) for incoming MPLS
segments to an LSR.
mplsOutSegmentPerfTable contains statistical information (total
packets received, total errored packets received, total packets
discarded, discontinuity time) for outgoing MPLS segments from an
LSR.
mplsFTNPerfTable contains performance information for the specified
interface and an FTN entry mapped to this interface.
mplsLdpEntityStatsTable and mplsLdpSessionStatsTable contain
statistical information (session attempts, errored packets,
notifications) about an LDP entity.
pwPerfCurrentTable, pwPerfIntervalTable, pwPerf1DayIntervalTable
provides pseudowire performance information (in and/or out packets)
based on time (current interval, each interval, 1day interval).
pwEnetStatsTable contains statistical counters specific for Ethernet
PW.
pwTDMPerfCurrentTable, pwTDMPerfIntervalTable and
pwTDMPerf1DayIntervalTable contain statistical informations
accumulated per 15-minute, 24 hour, 1 day respectively.
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gmplsTunnelErrorTable and gmplsTunnelReversePerfTable provides
information about performance errored packets and in/out packet
counters.
5.2.10. MIB Module Interdependencies
This section provides an overview of the relationship between the
MPLS MIB modules for managing MPLS networks. More details of these
relationships are given below.
[RFC4221] mainly focuses on the MPLS MIB module interdependencies,
this section also highlights the GMPLS and PW MIB modules
interdependencies.
The relationship "A --> B" means A depends on B and that MIB module
A uses an object, object identifier, or textual convention defined
in MIB module B, or that MIB module A contains a pointer (index or
RowPointer) to an object in MIB module B.
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+-------> MPLS-TC-STD-MIB <-----------------------------------------+
| ^ |
| | |
| MPLS-LSR-STD-MIB <--------------------------------+ |
| | |
+<----------------------- MPLS-LDP-STD-MIB ---------------->+ |
| ^ | |
| | | |
+<-- MPLS-LDP-GENERIC-STD-MIB ------>+ | |
| | |
+<------ MPLS-FTN-STD-MIB ---------+----------------------->+ |
| ^ | |
| | | |
+<------------- MPLS-TE-STD-MIB ->+ |
^ | GMPLS-TC-STD-MIB ------------>+
| | ^ |
| | | |
| +---+ +<-- GMPLS-LABEL-STD-MIB -->+
| | ^ ^ ^ |
| | | | | |
+----> PW-TC-STD-MIB | | GMPLS-LSR-STD-MIB --------------->+
| | | ^ ^ |
| | | | | |
| IANA-PWE3-MIB | | | | IANA-GMPLS-TC-MIB |
| ^ | | | | ^ |
| | | | | | | |
| | | +<--- GMPLS-TE-STD-MIB ------------->+
| | | ^ |
+<--- PW-STD-MIB <------+ | | |
| | | | |
+<--- PW-ENET-STD-MIB ->+ | | |
| ^ | | |
| | | | |
+<---------------- PW-MPLS-STD-MIB -------------------------------->+
Thus:
- All the MPLS MIB modules depend on MPLS-TC-STD-MIB.
- All the GMPLS MIB modules depend on GMPLS-TC-STD-MIB.
- All the PW MIB modules depend on PW-TC-STD-MIB.
- MPLS-LDP-STD-MIB, MPLS-TE-STD-MIB, MPLS-FTN-STD-MIB,
GMPLS-LSR-STD-MIB, and PW-MPLS-STD-MIB contain references to
objects in MPLS-LSR-STD-MIB.
- MPLS-LDP-GENERIC-STD-MIB contains references to objects in
MPLS-LDP-STD-MIB.
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- MPLS-FTN-STD-MIB, PW-MPLS-STD-MIB, and GMPLS-TE-STD-MIB contain
references to objects in MPLS-TE-STD-MIB.
- PW-MPLS-STD-MIB, and PW-ENET-STD-MIB contains references to
objects in PW-STD-MIB.
- PW-STD-MIB contains references to objects in IANA-PWE3-MIB.
- GMPLS-TE-STD-MIB contains references to objects in
IANA-GMPLS-TC-MIB.
- GMPLS-LSR-STD-MIB contains references to objects in
GMPLS-LABEL-STD-MIB.
Note that there is a textual convention (MplsIndexType) defined in
MPLS-LSR-STD-MIB that is imported by MPLS-LDP-STD-MIB.
5.2.11. Dependencies on External MIB Modules
MPLS MIB modules have dependencies with the TE-LINK-STD-MIB
for maintaining the traffic engineering information.
MPLS MIB modules depend on the CSPF module to get the paths for MPLS
tunnel to traverse to reach the end point of the tunnel and BFD
module to verify the data-plane failures of LSPs and PWs.
Finally, all of the MIB modules import standard textual conventions
such as integers, strings, timestamps, etc., from the MIB modules in
which they are defined.
This is business as usual for a MIB module and is not discussed
further in this document.
6. Applicability of MPLS MIB modules to MPLS-TP
In addition to the MPLS management overview [RFC4221]
section 4.12 (Dependencies on External MIB Modules), some of the
existing MPLS MIBs, PW MIBs and GMPLS MIBs are re-used with
extensions for achieving the MPLS-TP functionality.
[RFC5951] specifies the requirements for the management of
equipment used in networks supporting an MPLS-TP. It also details the
essential network management capabilities for operating networks
consisting of MPLS-TP equipment.
[RFC5950] provides the network management framework for
MPLS-TP. The document explains how network elements and networks that
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support MPLS-TP can be managed using solutions that satisfy the
requirements defined in [RFC5951]. The relationship between
MPLS-TP management and OAM is described in the MPLS-TP framework
[RFC5950] document.
Fault management and performance management form key parts of
Operations, Administration, and Maintenance (OAM) function. MPLS-TP
OAM is described in [MPLS-TP-OAM-FWK].
[Editors note - A seperate draft will provide an MPLS-TP abstract
model and use a formal language to define the terminology, the
information that must be retrieved and method for storing. The draft
will also list the new MPLS-TP MIB modules identified in this
document]
6.1 Gap Analysis
6.1.1 MPLS-TP Tunnel
o An MPLS tunnel may not compatible for non-IP environments.
i.e., the tunnel ingress and egress identifiers are not always
identified via an IP address, rather identification is achieved
using local numbers to operate in a non-IP environment.
o Next-hop IP address in MPLS XC table is not compatible for non-IP
environment.
o Bidirectional LSPs are not introduced until the GMPLS MIB modules,
tunnel table should be enhanced to provide static and signalling
corouted/associated bidirectional connectivity.
6.1.2 MPLS-TP Pseudowire
o MPLS pseudowire may not be compatible for non-IP environments.
i.e., pseudowire source and destination identifiers are not always
identified via an IP address, rather identification is achieved
using local numbers to operate in a non-IP environment.
o Pseudowire mib modules should be enhanced to operate over
corouted/associated bi-directional tunnel.
o Pseudowire 129 FEC type-2 should be used in non-IP and IP
environments with the required changes.
6.1.3 MPLS-TP Sections
There is no gap in the existing MPLS MIB modules as this MPLS-TP
section will be defined as the new term for MPLS-TP.
6.1.4 MPLS-TP OAM
MPLS manages the LSP and pseudowire faults through LSP ping
[RFC4379], VCCV [RFC5085], BFD for LSPs [RFC5884] and BFD for VCCV
[RFC5885] tools.
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There is no MIB management model currently available for the above
fault management tools.
There is no performance management tool currently available for MPLS
except the statistics information.
6.1.5 MPLS-TP Protection Switching
An important aspect that MPLS-TP technology provides is protection
switching. In general, the mechanism of protection switching
can be described as the substitution of a protection or standby
facility for a working or primary facility. An MPLS-TP protection
switching can be managed with the following parameters:
o Topology (linear, ring, mesh)
o Protection architecture (1+1, 1:1, or others as defined in
different topologies)
o Switching type (unidirectional, bidirectional)
o Operation mode (revertive, non-revertive)
o Automatic protection channel
o Protection state
o Position of the switch
o Timer values (hold-off, Wait-to-Restore)
o Failure of protocol
Among those parameters for protection switching, the topology on
that a protection switching applies has the most significant
influence on the other parameters. Besides, the mechanism of a
particular protection switching heavily depends on its topology.
Therefore, three MIB modules are to be defined to model and
manage each of three different topologies protection switching.
7. Interfaces
MPLS-TP can be carried over the existing and evolving physical
transport technologies such as SONET/SDH, OTN/WDM, and Ethernet.
The Interfaces Group of IF-MIB [RFC2863] defines generic managed
objects for managing interfaces. The MPLS-TP MIB modules make
references to interfaces so that it can be clearly determined where
the procedures managed by the MIB modules should be performed.
Additionally, the MPLS-TP MIB modules (notably MPLS-TE-STD-MIB and
TE-LINK-STD-MIB, PW-STD-MIB) utilize interface stacking within the
Interface Group.
Please refer to section 4. (Node and Interface Identifiers) in
[MPLS-TP-IDENTIFIERS] for more information on MPLS-TP specific
interfaces.
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7.1. MPLS Tunnels as Interfaces
An extension to mplsTunnelTable should address the tunnel
requirements specific to MPLS-TP.
MPLS Tunnel logical interfaces can be stacked over
PDH/SDH/OTH/Ethernet physical interfaces. For more information on
Tunnel interfaces, refer section 11.1 (MPLS Tunnels as Interfaces) of
RFC-4221.
7.2. Application of the Interfaces Group to TE Links
TE links can be formed over PDH/SDH/OTH/Ethernet physical interfaces.
For more information on TE links, Refer section 11.2. Application of
the Interfaces Group to TE Links of RFC-4221.
7.3. References to Interface Objects from MPLS MIB Modules
MPLSTP-STD-MIB includes the extensions of Tunnel table, PW table
for MPLS-TP.
More information on Tunnel interfaces can be found in the RFC-3812,
section 8. (Application of the Interface Group to MPLS Tunnels)
The PW in general is not an ifIndex on its own, for agent
scalability reasons. The PW is typically associated via
the PWE3 MIB modules to an ifIndex (physical entity) the PW is
emulating. Some implementations may manage the PW as an ifIndex in the
ifTable. A special ifType to represent a PW virtual interface (246)
will be used in the ifTable in this case. More information on PW
interfaces can be found in the RFC-5601, section 8 (PW relations to
the IF-MIB).
8. Management Options
It is not the intention of this document to provide instructions or
advice to implementers of management systems, management agents, or
managed entities. It is, however, useful to make some observations
about how the MIB modules described above might be used to manage
MPLS systems.
For MPLS specific management options, refer [RFC4221] Section 12
(Management Options).
[Editors Note: MPLS-TP specific management gaps and options will be
documented in this document and will be referenced here.]
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9. Security Considerations
This document describes the interrelationships amongst the different
MIB modules relevant to MPLS-TP management and as such does not have
any security implications in and of itself.
Each IETF MIB document that specifies MIB objects for MPLS-TP must
provide a proper security considerations section that explains the
security aspects of those objects.
The attention of readers is particularly drawn to the security
implications of making MIB objects available for create or write
access through an access protocol such as SNMP. SNMPv1 by itself is
an insecure environment. Even if the network itself is made secure
(for example, by using IPSec), there is no control over who on the
secure network is allowed to access the objects in this MIB. It is
recommended that the implementers consider the security features as
provided by the SNMPv3 framework. Specifically, the use of the
User-based Security Model STD 62, RFC3414 [RFC3414], and the
View-based Access Control Model STD 62, RFC 3415 [RFC3415],
is recommended.
It is then a customer/user responsibility to ensure that the SNMP
entity giving access to an instance of each MIB module is properly
configured to give access to only those objects, and to those
principals (users) that have legitimate rights to access them.
10. IANA Considerations
This document makes no requests for IANA action.
11. Acknowledgements
The authors would like to thank Eric Gray, Thomas Nadeau, Benjamin
Niven-Jenkins, Sam Aldrin and Anirban Karmakar for their valuable
comments.
12. References
12.1 Normative References
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB using SMIv2", RFC 2863, June 2000.
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[RFC3811] Nadeau, T. and J. Cucchiara, "Definition of Textual
Conventions and for Multiprotocol Label Switching (MPLS)
Management", RFC 3811, June 2004.
[RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Traffic
Engineering (TE) Management Information Base (MIB)",
RFC 3812, June 2004.
[RFC3813] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Label Switching
(LSR) Router Management Information Base (MIB)", RFC 3813,
June 2004.
[RFC3814] Nadeau, T., Srinivasan, C., and A. Viswanathan,
"Multiprotocol Label Switching (MPLS) FEC-To-NHLFE
(FTN) Management Information Base", RFC3814, June
2004.
[RFC3815] Cucchiara, J., Sjostrand, H., and Luciani, J.,
"Definitions of Managed Objects for the
Multiprotocol Label Switching (MPLS), Label
Distribution Protocol (LDP)", RFC 3815, June 2004.
[RFC4220] Dubuc, M., Nadeau, T., and J. Lang, "Traffic
Engineering Link Management Information Base", RFC
4220, November 2005.
[RFC4221] Nadeau, T., Srinivasan, C., and A. Farrel,
"Multiprotocol Label Switching (MPLS) Management
Overview", RFC 4221, November 2005.
[RFC4801] T. Nadeau and A. Farrel, Ed., "Definitions of Textual
Conventions for Generalized Multiprotocol Label Switching
(GMPLS) Management", RFC4801, Feb. 2007.
[RFC4802] T. D. Nadeau and A. Farrel, "Generalized Multiprotocol
Label Switching (GMPLS) Traffic Engineering Management
Information Base", RFC4802, Feb., 2007.
[RFC4803] T. D. Nadeau and A. Farrel, "Generalized Multiprotocol
Label Switching (GMPLS) Label Switching Router (LSR)
Management Information Base", RFC4803, Feb., 2007.
[RFC5542] Nadeau, T., Ed., Zelig, D., Ed., and O. Nicklass, Ed.,
"Definitions of Textual Conventions for Pseudowire (PW)
Management", RFC 5542, May 2009.
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[RFC5601] Nadeau, T., Ed. and D. Zelig, Ed. "Pseudowire (PW)
Management Information Base (MIB)", RFC 5601, July 2009.
[RFC5602] Zelig, D., Ed., and T. Nadeau, Ed., "Pseudowire (PW) over
MPLS PSN Management Information Base (MIB)", RFC 5602,
July 2009.
[RFC5603] Zelig, D., Ed., and T. Nadeau, Ed., "Ethernet Pseudowire
(PW) Management Information Base (MIB)", RFC 5603,
July 2009.
[RFC5604] Nicklass, O., "Managed Objects for Time Division
Multiplexing (TDM) over Packet Switched Networks (PSNs)",
RFC5604, July 2009.
12.2 Informative References
[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2
(SMIv2)", STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Textual Conventions for SMIv2", STD 58, RFC 2579,
April 1999.
[RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580,
April 1999.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon,
"Multiprotocol Label Switching Architecture", RFC 3031,
January 2001.
[RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart,
"Introduction and Applicability Statements for
Internet-Standard Management Framework", RFC 3410,
December 2002.
[RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security
Model (USM) for version 3 of the Simple Network
Management Protocol (SNMPv3)", STD 62, RFC 3414,
December 2002.
[RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based
Access Control Model (VACM) for the Simple Network
Management Protocol (SNMP)", STD 62, RFC 3415, December
2002.
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[RFC3931] Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling
Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005.
[RFC3945] Mannie, E. et.al., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", IETF RFC 3945, October
2004.
[RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-
Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005.
[RFC4197] Riegel, M., "Requirements for Edge-to-Edge Emulation of
Time Division Multiplexed (TDM) Circuits over Packet
Switching Networks", RFC4197, October 2005.
[RFC4377] Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S.
Matsushima, "Operations and Management (OAM) Requirements
for Multi-Protocol Label Switched (MPLS) Networks",
RFC 4377, February 2006.
[RFC4378] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol
Label Switching (MPLS) Operations and Management (OAM)",
RFC 4378, February 2006.
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
[RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and
G. Heron, "Pseudowire Setup and Maintenance Using the
Label Distribution Protocol (LDP)", RFC 4447,
April 2006.
[RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual
Circuit Connectivity Verification (VCCV): A Control
Channel for Pseudowires", RFC 5085, December 2007.
[RFC5654] Niven-Jenkins, B., et al, "MPLS-TP Requirements",
RFC5654, September 2009.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) For MPLS
Label Switched Paths (LSPs)", RFC 5884, June 2010.
[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional
Forwarding Detection (BFD) for the Pseudowire
Virtual Circuit Connectivity Verification (VCCV)",
RFC5885, June 2010.
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[RFC5950] Gray, E., Mansfield, S., Lam, K.,
"MPLS-TP Network Management Framework", RFC 5950,
September 2010.
[RFC5951] Gray, E., Mansfield, S., Lam, K., "MPLS TP
Network Management Requirements", RFC 5951, September
2010.
[MPLS-TP-IDENTIFIERS] Bocci, M., Swallow, G., "MPLS-TP Identifiers"
draft-ietf-mpls-tp-identifiers-03, October 2010.
[MPLS-TP-OAM-FWK] Busi, I. and B. Niven-Jenkins, "MPLS-TP OAM
Framework and Overview", 2009,
<draft-ietf-mpls-tp-oam-framework>.
14. Authors' Addresses
Adrian Farrel
Old Dog Consulting
UK
Email: adrian@olddog.co.uk
Daniel King
Old Dog Consulting
UK
Email: daniel@olddog.co.uk
Venkatesan Mahalingam
Aricent
India
Email: venkatesan.mahalingam@aricent.com
Scott Mansfield
Ericsson
300 Holger Way, San Jose, CA 95134, US
Phone: +1 724 931 9316
Email: scott.mansfield@ericsson.com
Jeong-dong Ryoo
ETRI
161 Gajeong, Yuseong, Daejeon, 305-700, South Korea
Phone: +82 42 860 5384
Email: ryoo@etri.re.kr
A S Kiran Koushik
Cisco Systems Inc.
Email: kkoushik@cisco.com
A. Karmakar
Cisco Systems Inc.
Email: akarmaka@cisco.com
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