Internet DRAFT - draft-ietf-mpls-tp-rosetta-stone
draft-ietf-mpls-tp-rosetta-stone
MPLS Working Group H. van Helvoort (Ed)
Internet Draft Huawei Technologies
Intended status: Informational
Expires: April 2014 L. Andersson (Ed)
Huawei Technologies
N. Sprecher (Ed)
Nokia Solutions and Networks
October 20, 2013
A Thesaurus for the Terminology used in Multiprotocol Label
Switching Transport Profile (MPLS-TP) drafts/RFCs and ITU-T's
Transport Network Recommendations.
draft-ietf-mpls-tp-rosetta-stone-13
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Abstract
MPLS Transport Profile (MPLS-TP) is based on a profile of the MPLS
and Pseudowire (PW) procedures as specified in the MPLS-TE, PW and
Multi-Segment Pseudowire (MS-PW) architectures developed by the
Internet Engineering Task Force (IETF). The International
Telecommunications Union Telecommunications Standardization Sector
(ITU-T) has specified a Transport Network architecture.
This document provides a thesaurus for the interpretation of MPLS-TP
terminology within the context of the ITU-T Transport Network
Recommendations.
It is important to note that MPLS-TP is applicable in a wider set of
contexts than just Transport Networks. The definitions presented in
this document do not provide exclusive nor complete interpretations
of MPLS-TP concepts. This document simply allows the MPLS-TP terms
to be applied within the Transport Network context.
Table of Contents
1 Introduction 4
1.1 Contributing Authors 4
1.2 Abbreviations 4
2 Terminology 6
2.1 MPLS-TP Terminology Sources 6
2.2 ITU-T Transport Network Terminology Sources 6
2.3 Common Terminology Sources 6
3 Thesaurus 6
3.1 Associated bidirectional path: 6
3.2 Bidirectional path: 7
3.3 Client layer network: 7
3.4 Communication Channel: 7
3.5 Concatenated Segment: 7
3.6 Control Plane: 7
3.7 Co-routed bidirectional path: 7
3.8 Data Communication Network (DCN): 8
3.9 Defect: 8
3.10 Domain: 8
3.11 Embedded Communication Channel (ECC): 8
3.12 Equipment Management Function (EMF): 8
3.13 Failure: 8
3.14 Fault: 9
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3.15 Layer network: 9
3.16 Link: 9
3.17 Maintenance Entity (ME): 9
3.18 Maintenance Entity Group (MEG): 10
3.19 Maintenance Entity Group End Point (MEP): 10
3.20 Maintenance Entity Group Intermediate Point (MIP): 11
3.21 Management Communication Channel (MCC): 11
3.22 Management Communication Network (MCN): 11
3.23 Monitoring 11
3.23.1 Path Segment Tunnel (PST): 12
3.23.2 Sub-Path Maintenance Element (SPME): 12
3.23.3 Tandem Connection: 12
3.24 MPLS Section: 13
3.25 MPLS Transport Profile (MPLS-TP): 13
3.26 MPLS-TP NE: 13
3.27 MPLS-TP network: 13
3.28 MPLS-TP Recovery: 13
3.28.1 End-to-end recovery: 13
3.28.2 Link recovery: 13
3.28.3 Segment recovery: 13
3.29 MPLS-TP Ring Topology: 13
3.29.1 MPLS-TP Logical Ring: 14
3.29.2 MPLS-TP Physical Ring: 14
3.30 OAM flow: 14
3.31 Operations System (OS): 14
3.32 Path: 14
3.33 Protection priority: 14
3.34 Section Layer Network: 14
3.35 Segment: 15
3.36 Server layer: 15
3.37 Server MEPs: 15
3.38 Signaling Communication Channel (SCC): 16
3.39 Signaling Communication Network (SCN): 16
3.40 Span: 16
3.41 Sublayer: 16
3.42 Transport Entity: 16
3.42.1 Working Entity: 16
3.42.2 Protection Entity: 17
3.42.3 Recovery entity: 17
3.43 Transmission media layer: 17
3.44 Transport Network: 17
3.45 Transport path: 17
3.46 Transport path layer: 17
3.47 Transport service layer: 18
3.48 Unidirectional path: 18
4 Guidance on the Application of this Thesaurus 18
5 Management Considerations 18
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6 Security Considerations 18
7 IANA Considerations 19
8 Acknowledgments 19
9 References 19
9.1 Normative References 19
9.2 Informative References 20
1 Introduction
Multiprotocol Label Switching - Transport Profile (MPLS-TP) has been
developed by the IETF to facilitate the Operation, Administration
and Management of Label Switched Paths (LSPs) to be used in a
Transport Network environment as defined by the ITU-T.
The ITU-T has specified a Transport Network architecture for the
transfer of signals from different technologies. This architecture
forms the basis of many Recommendations within the ITU-T.
Because of the difference in historic background of MPLS, and
inherently MPLS-TP (the Internet) and the Transport Network (ITU
Telecommunication Sector), the terminology used is different.
This document provides a thesaurus for the interpretation of MPLS-TP
terminology within the context of the ITU-T Transport Network
Recommendations. This allows MPLS-TP documents to be generally
understood by those familiar with MPLS RFCs. The definitions
presented in this document do not provide exclusive or complete
interpretations of the ITU-T Transport Network concepts.
1.1 Contributing Authors
Italo Busi, Ben Niven-Jenkins, Enrique Hernandez-Valencia, Lieven
Levrau, Dinesh Mohan, Stuart Bryant, Dan Frost, Matthew Bocci,
Vincenzo Sestito, Vigoureux, Yaacov Weingarten
1.2 Abbreviations
CE Customer Edge
DCC Data Communication Channel
DCN Data Communication Network
ECC Embedded Communication Channel
EMF Equipment Management Function
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EMS Element Management System
GAL Generic Associated Channel Label
NEF Network Element Function
LER Label Edge Router
LSR Label Switching Router
MCC Management Communication Channel
MCN Management Communication Network
ME Maintenance Entity
MEG Maintenance Entity Group
MEP Maintenance Entity Group End Point
MIP Maintenance Entity Group Intermediate Point
MPLS Multiprotocol Label Switching
MPLS-TP MPLS Transport Profile
MS-PW Multi-Segment Pseudowire
NE Network Element
OAM Operations, Administration, and Maintenance
OSS Operations Support System
PM Performance Monitoring
PST Path Segment Tunnel
PW Pseudowire
S-PE PW Switching Provider Edge
SCC Signaling Communication Channel
SCN Signaling Communication Network
SPME Sub-Path Maintenance Element
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T-PE PW Terminating Provider Edge
TCM Tandem Connection Monitoring
2 Terminology
2.1 MPLS-TP Terminology Sources
MPLS-TP terminology is principally defined in [RFC3031]. Other
documents provide further key definitions including [RFC4397].
2.2 ITU-T Transport Network Terminology Sources
The ITU-T Transport Network is specified in a number of
Recommendations: generic functional architectures and requirements
are specified in [ITU-T_G.805], [ITU-T_G.806], and [ITU-T_G.872].
ITU-T Recommendation [ITU-T_G.8101] contains an overview of the
Terms and Definitions for transport MPLS.
2.3 Common Terminology Sources
The work in this document builds on the shared view of MPLS
requirements. It is intended to provide a source for common MPLS-TP
terminology. In general the original terminology is used.
The following sources are used:
IETF framework and requirements RFCs: [RFC6371], [RFC6372],
[RFC5654], [RFC5921], [RFC5860], [RFC5951], [RFC3031] and [RFC4397].
ITU-T architecture and requirements Recommendations: [ITU-T_G.8101],
[ITU-T_G.805], [ITU-T_G.806], [ITU-T_G.872], [ITU-T G.7710] and
[ITU-T Y.2611].
3 Thesaurus
3.1 Associated bidirectional path:
A path that supports traffic flow in both directions but that is
constructed from a pair of unidirectional paths (one for each
direction) that are associated with one another at the path's
ingress/egress points. An associated bidirectional path needs not
be a single management and operational entity. The forward and
backward directions are setup, monitored, and protected
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independently. As a consequence, they may or may not follow the
same route (links and nodes) across the network.
3.2 Bidirectional path:
A path that supports traffic flow in two opposite directions, i.e.
the forward and backward direction.
3.3 Client layer network:
In a client/server relationship (see [ITU-T_G.805]), the client
layer network receives a (transport) service from the lower server
layer network (usually the layer network under consideration).
3.4 Communication Channel:
A logical channel between network elements (NEs) that can be used -
e.g. - for management plane application or control plane
applications. The physical channel supporting the Communication
Channel is technology specific. See [RFC5951] Appendix A.
3.5 Concatenated Segment:
A serial-compound link connection as defined in [ITU-T_G.805]. A
concatenated segment is a contiguous part of an LSP or MS-PWthat
comprises a set of segments and their interconnecting nodes in
sequence. See also "Segment".
3.6 Control Plane:
Within the scope of [RFC5654], the control plane performs transport
path control functions. Through signalling, the control plane sets
up, modifies and releases transport paths, and may recover a
transport path in case of a failure. The control plane also
performs other functions in support of transport path control, such
as routing information dissemination. It is possible to operate an
MPLS-TP network without using a Control Plane.
3.7 Co-routed bidirectional path:
A path where the forward and backward directions follow the same
route (links and nodes) across the network. A co-routed
bidirectional path is managed and operated as a single entity. Both
directions are setup, monitored and protected as a single entity. A
transport network path is typically co-routed.
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3.8 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 routing and signaling communications related to the
control plane, and other operations communications (e.g., order-
wire/voice communications, software downloads, etc.).
3.9 Defect:
The situation for which 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
(PM), the control of consequent actions, and the determination of
fault cause. See also [ITU-T_G.806].
3.10 Domain:
A domain represents a collection of entities (for example network
elements) that are grouped for a particular purpose, examples of
which are administrative and/or managerial responsibilities, trust
relationships, addressing schemes, infrastructure capabilities,
aggregation, survivability techniques, distributions of control
functionality, etc. Examples of such domains include IGP areas and
Autonomous Systems.
3.11 Embedded Communication Channel (ECC):
A logical operations channel between network elements (NEs) that can
be utilized by multiple applications (e.g., management plane
applications, control plane applications, etc.). The physical
channel supporting the ECC is technology specific. An example of a
physical channel supporting the ECC is a Data Communication Channel
(DCC) within SDH.
3.12 Equipment Management Function (EMF):
The equipment management function (EMF) provides the means through
which an element management system (EMS) and other managing entities
manage the network element function (NEF). See [ITU-T G.7710].
3.13 Failure:
A failure is a detected fault. A failure will be declared when the
fault cause persisted long enough to consider the ability of an item
to perform a required transport function to be terminated. The item
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may be considered as failed; a fault has now been detected. See
also [ITU-T_G.806]. A failure can be used as a trigger for
corrective actions.
3.14 Fault:
A Fault is the inability of a transport function to perform a
required action. This does not include an inability due to
preventive maintenance, lack of external resources, or planned
actions. See also [ITU-T_G.806].
3.15 Layer network:
Layer network is defined in [ITU-T_G.805]. A layer network provides
for the transfer of client information and independent operation of
the client OAM. A layer network may be described in a service
context as follows: one layer network may provide a (transport)
service to a higher client layer network and may, in turn, be a
client to a lower-layer network. A layer network is a logical
construction somewhat independent of arrangement or composition of
physical network elements. A particular physical network element
may topologically belong to more than one layer network, depending
on the actions it takes on the encapsulation associated with the
logical layers (e.g., the label stack), and thus could be modeled as
multiple logical elements. A layer network may consist of one or
more sublayers. For additional explanation of how layer networks
relate to the OSI concept of layering, see Appendix I of [ITU-T
Y.2611].
3.16 Link:
A physical or logical connection between a pair of Label Switching
Routers (LSRs) that are adjacent at the (sub)layer network under
consideration. A link may carry zero, one or more LSPs or PWs. A
packet entering a link will emerge with the same label stack entry
values.
A link as defined in [ITU-T_G.805] is used to describe a fixed
relationship between two ports.
3.17 Maintenance Entity (ME):
A Maintenance Entity (ME) can be viewed as the association of two
(or more) Maintenance Entity Group End Points (MEPs), that should be
configured and managed in order to bound the OAM responsibilities of
an OAM flow across a network or sub-network, i.e. a transport path
or segment, in the specific layer network that is being monitored
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and managed. See also [RFC6371] section 3.1 and [ITU-T G.8113.1],
[ITU-T G.8113.2] clause 6.1.
A Maintenance Entity may be defined to monitor and manage
bidirectional or unidirectional point-to-point connectivity or
point-to-multipoint connectivity in an MPLS-TP layer network.
Therefore, in the context of a MPLS-TP LSP ME or PW ME Label Edge
Routers (LERs) and PW Terminating Provider Edges (T-PEs) can be MEPs
while LSRs and PW Switching Provider Edges (S-PEs) can be MIPs. In
the case of a ME for a Tandem Connection, LSRs and S-PEs can be
either MEPs or MIPs.
The following properties apply to all MPLS-TP MEs:
= OAM entities can be nested but not overlapped.
= Each OAM flow is associated to a unique Maintenance Entity.
= OAM packets are subject to the same forwarding treatment as the
data traffic, but they are distinct from the data traffic by the
Generic Associated Channel Label (GAL).
3.18 Maintenance Entity Group (MEG):
A Maintenance Entity Group is defined, for the purpose of connection
monitoring, between a set of connection points within a connection.
This set of connection points may be located at the boundary of one
administrative domain or a protection domain, or the boundaries of
two adjacent administrative domains. The MEG may consist of one or
more Maintenance Entities (ME). See also [RFC6371] section 3.1 and
[ITU-T G.8113.1], [ITU-T G.8113.2] clause 6.2.
In an MPLS-TP layer network a MEG consists of only one ME.
3.19 Maintenance Entity Group End Point (MEP):
Maintenance Entity Group End Points (MEPs) are the end points of a
pre-configured (through the management or control planes) ME. MEPs
are responsible for activating and controlling all of the OAM
functionality for the ME. A source MEP may initiate an OAM packet to
be transferred to its corresponding peer or sink MEP, or to an
intermediate MIP that is part of the ME. See also [RFC6371] section
3.3 and [ITU-T G.8113.1], [ITU-T G.8113.2] clause 6.3.
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A sink MEP terminates all the OAM packets that it receives
corresponding to its ME and does not forward them further along the
path.
All OAM packets coming into a source MEP are tunnelled via label
stacking and are not processed within the ME as they belong either
to the client network layers or to a higher Tandem Connection
Monitoring (TCM) level.
A MEP in a tandem connection is not coincident with the termination
of the MPLS-TP transport path (LSP or PW), though it can monitor its
connectivity (e.g. count packets). A MEP of an MPLS-TP network
transport path is coincident with transport path termination and
monitors its connectivity (e.g. counts packets).
An MPLS-TP sink MEP can notify a fault condition to its MPLS-TP
client layer network.
3.20 Maintenance Entity Group Intermediate Point (MIP):
A Maintenance Entity Group Intermediate Point (MIP) is a point
between the two MEPs in an ME and is capable of responding to some
OAM packets and forwarding all OAM packets while ensuring fate
sharing with data plane packets. A MIP responds only to OAM packets
that are sent on the ME it belongs to and that are addressed to the
MIP, it does not initiate OAM messages. See also [RFC6371] section
3.4 and [ITU-T G.8113.1], [ITU-T G.8113.2] clause 6.4.
3.21 Management Communication Channel (MCC):
A Communication Channel dedicated for management plane
communications.
3.22 Management Communication Network (MCN):
A DCN supporting management plane communication is referred to as a
Management Communication Network (MCN).
3.23 Monitoring
Monitoring is applying OAM functionality to verify and to maintain
the performance and the quality guarantees of a transport path.
There is a need to not only monitor the whole transport path (e.g.
LSP or MS-PW), but also arbitrary parts of transport paths. The
connection between any two arbitrary points along a transport path
is described in one of three ways:
- as a Path Segment Tunnel,
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- as a Sub-Path Maintenance Element, or
- as a Tandem Connection.
3.23.1 Path Segment Tunnel (PST):
A path segment is either a segment or a concatenated segment. Path
Segment Tunnels (PSTs) are instantiated to provide monitoring of a
portion of a set of co-routed transport paths (LSPs or MS-PWs).
Path segment tunnels can also be employed to meet the requirement to
provide Tandem Connection Monitoring, see Tandem Connection.
3.23.2 Sub-Path Maintenance Element (SPME):
To monitor, protect, and manage a portion (i.e., segment or
concatenated segment) of an LSP, a hierarchical LSP [RFC3031] can be
instantiated. A hierarchical LSP instantiated for this purpose is
called a Sub-Path Maintenance Element (SPME). Note that by
definition an SPME does not carry user traffic as a direct client.
An SPME is defined between the edges of the portion of the LSP that
needs to be monitored, protected or managed. The SPME forms a MPLS-
TP Section that carries the original LSP over this portion of the
network as a client. OAM messages can be initiated at the edge of
the SPME and sent to the peer edge of the SPME or to a MIP along the
SPME. A P router only pushes or pops a label if it is at the end of
a SPME. In this mode, it is an LER for the SPME.
3.23.3 Tandem Connection:
A tandem connection is an arbitrary part of a transport path that
can be monitored (via OAM) independently from the end-to-end
monitoring (OAM). It may be a monitored segment, a monitored
concatenated segment or any other monitored ordered sequence of
contiguous hops and/or segments (and their interconnecting nodes) of
a transport path.
Tandem Connection Monitoring (TCM) for a given path segment of a
transport path is implemented by creating a path segment tunnel that
has a 1:1 association with the path segment of the transport path
that is to be uniquely monitored. This means that the PST used to
provide TCM can carry one and only one transport path thus allowing
direct correlation between all fault management and performance
monitoring information gathered for the PST and the monitored path
segment of the end-to-end transport path. The PST is monitored
using normal LSP monitoring. See also [RFC6371] section 3.2 and
[ITU-T G.8113.1], [ITU-T G.8113.2] clause 6.2.1.
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3.24 MPLS Section:
A network segment between two LSRs that are immediately adjacent at
the MPLS layer.
3.25 MPLS Transport Profile (MPLS-TP):
The set of MPLS functions used to support packet transport services
and network operations.
3.26 MPLS-TP NE:
A network element (NE) that supports MPLS-TP functions.
3.27 MPLS-TP network:
A network in which MPLS-TP NEs are deployed.
3.28 MPLS-TP Recovery:
3.28.1 End-to-end recovery:
MPLS-TP End-to-end recovery refers to the recovery of an entire LSP,
from its ingress to its egress node.
3.28.2 Link recovery:
MPLS-TP link recovery refers to the recovery of an individual link
(and hence all or a subset of the LSPs routed over the link) between
two MPLS-TP nodes. For example, link recovery may be provided by
server layer recovery.
3.28.3 Segment recovery:
MPLS-TP Segment recovery refers to the recovery of an LSP segment
(i.e., segment and concatenated segment) between two nodes and is
used to recover from the failure of one or more links or nodes.
An LSP segment comprises one or more contiguous hops on the path of
the LSP. [RFC5654] defines two terms. A "segment" is a single hop
along the path of an LSP, while a "concatenated segment" is more
than one hop along the path of an LSP.
3.29 MPLS-TP Ring Topology:
In an MPLS-TP ring topology, each LSR is connected to exactly two
other LSRs, each via a single point-to-point bidirectional MPLS-TP
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capable link. A ring may also be constructed from only two LSRs
where there are also exactly two links. Rings may be connected to
other LSRs to form a larger network. Traffic originating or
terminating outside the ring may be carried over the ring. Client
network nodes (such as Customer Edges (CEs)) may be connected
directly to an LSR in the ring.
3.29.1 MPLS-TP Logical Ring:
An MPLS-TP logical ring is constructed from a set of LSRs and
logical data links (such as MPLS-TP LSP tunnels or MSPL-TP
pseudowires) and physical data links that form a ring topology.
3.29.2 MPLS-TP Physical Ring:
An MPLS-TP physical ring is constructed from a set of LSRs and
physical data links that form a ring topology.
3.30 OAM flow:
An OAM flow is the set of all OAM packets originating with a
specific source MEP that instrument one direction of a MEG (or
possibly both in the special case of data plane loopback).
3.31 Operations Support System (OSS):
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.
3.32 Path:
See Transport path.
3.33 Protection priority:
Fault conditions (e.g., signal failed), external commands (e.g,
forced switch, manual switch) and protection states (e.g., no
request) are defined to have a relative priority with respect to
each other. Priority is applied to these conditions/command/states
locally at each end point and between the two end points.
3.34 Section Layer Network:
A section layer is a server layer (which may be MPLS-TP or a
different technology) that provides for the transfer of the section-
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layer client information between adjacent nodes in the transport-
path layer or transport-service layer. A section layer may provide
for aggregation of multiple MPLS-TP clients. Note that [ITU-
T_G.805] defines the section layer as one of the two layer networks
in a transmission-media layer network. The other layer network is
the physical-media layer network.
Section layer networks are concerned with all the functions which
provide for the transfer of information between locations in path
layer networks.
Physical media layer networks are concerned with the actual fibres,
metallic wires or radio frequency channels which support a section
layer network.
3.35 Segment:
A link connection as defined in [ITU-T_G.805]. A segment is the
part of an LSP that traverses a single link or the part of a PW that
traverses a single link (i.e., that connects a pair of adjacent S-
PEs and/or T-PEs). See also "Concatenated Segment".
3.36 Server layer:
A server layer is a layer network in which transport paths are used
to carry a customer's (individual or bundled) service (may be point-
to-point, point-to-multipoint or multipoint-to-multipoint services).
In a client/server relationship (see [ITU-T_G.805]) the server layer
network provides a (transport) service to the higher client layer
network (usually the layer network under consideration).
3.37 Server MEPs:
A server MEP is a MEP of an ME that is defined in a layer network
below the MPLS-TP layer network being referenced. A server MEP
coincides with either a MIP or a MEP in the client (MPLS-TP) layer
network. See also [RFC6371] section 3.5 and [ITU-T G.8113.1] clause
6.5.
For example, a server MEP can be either:
. A termination point of a physical link (e.g. IEEE 802.3), an SDH
VC or OTH ODU for the MPLS-TP Section layer network, defined in
[RFC6371] section 3.1.;
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. An MPLS-TP Section MEP for MPLS-TP LSPs, defined in [RFC6371]
section 3.2.;
. An MPLS-TP LSP MEP for MPLS-TP PWs, defined in [RFC6371] section
3.4.;
. An MPLS-TP TCM MEP for higher-level TCMs, defined in [RFC6371]
sections 3.3. and 3.5.
The server MEP can run appropriate OAM functions for fault
detection, and notifies a fault indication to the MPLS-TP layer
network.
3.38 Signaling Communication Channel (SCC):
A Communication Channel dedicated for control plane communications.
The SCC may be used for GMPLS/ASON signaling and/or other control
plane messages (e.g., routing messages).
3.39 Signaling Communication Network (SCN):
A DCN supporting control plane communication is referred to as a
Signaling Communication Network (SCN).
3.40 Span:
A span is synonymous with a link.
3.41 Sublayer:
Sublayer is defined in [ITU-T_G.805]. The distinction between a
layer network and a sublayer is that a sublayer is not directly
accessible to clients outside of its encapsulating layer network and
offers no direct transport service for a higher layer (client)
network.
3.42 Transport Entity:
A "Transport Entity" is a node, link, transport path segment,
concatenated transport path segment, or entire transport path.
3.42.1 Working Entity:
A "Working Entity" is a transport entity that carries traffic during
normal network operation.
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3.42.2 Protection Entity:
A "Protection Entity" is a transport entity that is pre-allocated
and used to protect and transport traffic when the working entity
fails.
3.42.3 Recovery entity:
A "Recovery Entity" is a transport entity that is used to recover
and transport traffic when the working entity fails.
3.43 Transmission media layer:
A layer network, consisting of a section layer network and a
physical layer network as defined in [ITU-T_G.805], that provides
sections (two-port point-to-point connections) to carry the
aggregate of network-transport path or network-service layers on
various physical media.
3.44 Transport Network:
A Transport Network provides transmission of traffic between
attached client devices by establishing and maintaining point-to-
point or point-to-multipoint connections between such devices. A
Transport Network is independent of any higher-layer network that
may exist between clients, except to the extent required to supply
this transmission service. In addition to client traffic, a
Transport Network may carry traffic to facilitate its own operation,
such as that required to support connection control, network
management, and Operations, Administration and Maintenance (OAM)
functions.
3.45 Transport path:
A network connection as defined in [ITU-T_G.805]. In an MPLS-TP
environment a transport path corresponds to an LSP or a PW.
3.46 Transport path layer:
A (sub)layer network that provides point-to-point or point-to-
multipoint transport paths. It provides OAM that is independent of
the clients that it is transporting.
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3.47 Transport service layer:
A layer network in which transport paths are used to carry a
customer's (individual or bundled) service (may be point-to-point,
point-to-multipoint or multipoint-to-multipoint services).
3.48 Unidirectional path:
A Unidirectional Path is a path that supports traffic flow in only
one direction.
4 Guidance on the Application of this Thesaurus
As discussed in the introduction to this document, this thesaurus is
intended to bring the concepts and terms associated with MPLS-TP
into the context of the ITU-T's Transport Network architecture.
Thus, it should help those familiar with MPLS to see how they may
use the features and functions of the Transport Network in order to
meet the requirements of MPLS-TP.
5 Management Considerations
The MPLS-TP based network requires management. The MPLS-TP
specifications described in [RFC5654], [RFC5860], [RFC5921],
[RFC5951], [RFC6371], [RFC6372], [ITU-T G.8110.1] and [ITU-T
G.7710], include considerable efforts to provide operator control
and monitoring, as well as Operations, Administration and
Maintenance (OAM) functionality.
These concepts are, however, out of scope of this document.
6 Security Considerations
Security is a significant requirement of MPLS-TP. See for more
information [RFC6941].
However, this informational document is intended only to provide
lexicography, and the security concerns are, therefore, out of
scope.
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7 IANA Considerations
There are no IANA actions resulting from this document.
8 Acknowledgments
The authors would like to thank all members of the teams (the Joint
Working Team, the MPLS Interoperability Design Team in IETF and the
MPLS-TP Ad Hoc Group in ITU-T) involved in the definition and
specification of MPLS Transport Profile. We would in particular like
to acknowledge the contributions by Tom Petch to improve the quality
of this draft.
9 References
9.1 Normative References
[RFC3031] Rosen, E., Viswanathan, A., and Callon, R., "Multiprotocol
Label Switching Architecture", January 2001.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., et al.,
"Requirements of an MPLS Transport Profile", September
2009.
[RFC5860] Vigoureux, M., Ward, D., Betts, M., "Requirements for OAM
in MPLS Transport Networks", May 2010.
[RFC5921] Bocci, M., Bryant, S., Frost, D, et al., "A Framework for
MPLS in Transport Networks", July 2010.
[RFC5951] Lam, K., Gray, E., Mansfield, S., "Network Management
Requirements for MPLS-based Transport Networks", September
2010.
[RFC6371] Busi, I., Allan, D., "Operations, Administration, and
Maintenance Framework for MPLS-Based Transport Networks",
September 2011.
[RFC6372] Sprecher, N., Farrel, A., "MPLS Transport Profile (MPLS-
TP) Survivability Framework", September 2011.
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For information on the availability of the following documents,
please see http://www.itu.int
[ITU-T_G.805] ITU-T Recommendation G.805 (03/2000), "Generic
functional architecture of transport networks."
[ITU-T_G.806] ITU-T Recommendation G.806 (03/2006), "Characteristics
of transport equipment - Description methodology and
generic functionality."
[ITU-T_G.872] ITU-T Recommendation G.872 (11/2001), "Architecture of
optical transport networks."
[ITU-T G.7710] ITU-T Recommendation G.7710 (07/2007), "Common
equipment management function requirements."
[ITU-T_G.8101] ITU-T Recommendation G.8101/Y.1355 (09/2013), "Terms
and definitions for MPLS Transport Profile."
[ITU-T G.8110.1] ITU-T Recommendation G.8110.1/Y.1370.1 (12/2011),
"Architecture of the Multi-Protocol Label Switching
transport profile layer network."
[ITU-T G.8113.1] ITU-T Recommendation G.8113.1/Y.1372.1 (11/2012),
"Operations, Administration and Maintenance mechanism
for MPLS-TP in Packet Transport Network (PTN)."
[ITU-T G.8113.2] ITU-T Recommendation G.8113.2/Y.1372.2 (11/2012),
"Operations, administration and maintenance mechanisms
for MPLS-TP networks using the tools defined for
MPLS."
[ITU-T Y.2611] ITU-T Recommendation Y.2611 (12/2006), "High-level
architecture of future packet-based networks."
9.2 Informative References
[RFC4397] I. Bryskin, A. Farrel, "A Lexicography for the
Interpretation of Generalized Multiprotocol Label
Switching (GMPLS) Terminology within the Context of the
ITU-T's Automatically Switched Optical Network (ASON)
Architecture", February 2006.
[RFC6941] L. Fang, B. Niven-Jenkins, S. Mansfield, R. Graveman,
"MPLS Transport Profile (MPLS-TP) Security Framework",
April 2013.
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Authors' Addresses
Huub van Helvoort (Editor)
Huawei Technologies Co., Ltd.
Email: Huub.van.Helvoort@huawei.com
Loa Andersson (Editor)
Huawei Technologies Co., Ltd.
Email: loa@mail01.huawei.com
Nurit Sprecher (Editor)
Nokia Solutions and Networks
Email: nurit.sprecher@nsn.com
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