Network Working Group B. Niven-Jenkins, Ed.
Internet-Draft BT
Intended status: Informational D. Brungard, Ed.
Expires: January 4, 2009 AT&T
M. Betts, Ed.
Nortel Networks
N. Sprecher
Nokia Siemens Networks
July 03, 2008
MPLS-TP Requirements
draft-jenkins-mpls-mpls-tp-requirements-00
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Abstract
This document specifies the requirements for a MPLS Transport Profile
(MPLS-TP). This document is a product of a joint ITU-IETF effort to
include a MPLS Transport Profile within the IETF MPLS architecture to
support the capabilities and functionalities of a packet transport
network as defined by ITU-T.
This work is based on two sources of requirements, MPLS architecture
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as defined by IETF and packet transport networks as defined by ITU-T.
Requirements Language
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 [RFC2119].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Transport network overview . . . . . . . . . . . . . . . . 5
2. MPLS-TP Requirements . . . . . . . . . . . . . . . . . . . . . 6
2.1. General requirements . . . . . . . . . . . . . . . . . . . 6
2.2. Layering requirements . . . . . . . . . . . . . . . . . . 7
2.3. Data plane requirements . . . . . . . . . . . . . . . . . 8
2.4. Control plane requirements . . . . . . . . . . . . . . . . 9
2.5. Network Management (NM) requirements . . . . . . . . . . . 11
2.6. OAM requirements . . . . . . . . . . . . . . . . . . . . . 12
2.7. Network performance management (PM) requirements . . . . . 12
2.8. Protection & Survivability requirements . . . . . . . . . 12
2.9. QoS requirements . . . . . . . . . . . . . . . . . . . . . 15
2.10. Security requirements . . . . . . . . . . . . . . . . . . 16
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
4. Security Considerations . . . . . . . . . . . . . . . . . . . 16
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
6. Informative References . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
Intellectual Property and Copyright Statements . . . . . . . . . . 19
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1. Introduction
For many years, SONET/SDH has provided service providers with a high
benchmark for reliability and operational simplicity. With the
accelerating growth of packet-based services (such as Ethernet, VoIP,
L2/L3 VPN, IPTV, RAN backhauling, etc.), service providers are in
need of capabilities to efficiently support packet-based services on
their transport networks. The need to increase their revenue while
remaining competitive forces operators to look for the lowest network
Total Cost of Ownership (TCO). Investment in both Capital
Expenditure (CAPEX) and Operational Expense (OPEX) should be minimal.
Carriers are considering migrating to packet transport networks in
order to reduce their costs and to improve their ability to support
services with guaranteed SLAs. Migrating from SONET/SDH to packet
transport networks should not involve dramatic changes in network
operation, should not necessitate extensive retraining, and should
not require major changes to existing work practices. The aim is to
preserve the look-and-feel to which carriers have become accustomed
in deploying their SONET/SDH networks, while providing common, multi-
layer operations, resiliency, control and management for packet,
circuit and lambda transport networks.
Service providers require control and deterministic usage of network
resources. They need end-to-end control to engineer network paths
and to efficiently utilize network resources. They require
capabilities to support static (OSS based) or dynamic (control plane)
provisioning of deterministic, protected and secured services and
their associated resources as well as alternative control-plane
options.
Carriers will still need to cope with legacy networks (which are
composed of many layers and technologies), thus the packet transport
network should interwork with other packet and transport networks
(both horizontally and vertically). Vertical interworking is also
known as client/server or network interworking. Horizontal
interworking is also known as peer-partition or service interworking.
For more details on each type of interworking and some of the issues
that may arise (especially with horizontal interworking) see
[ITU.Y1401.2008].
MPLS is a maturing packet technology and it is already playing an
important role in transport networks and services. However, not all
of MPLS's capabilities and mechanisms are needed and/or consistent
with transport network operations. There is therefore the need to
define an MPLS Transport Profile (MPLS-TP) in order to support the
capabilities and functionalities needed for packet transport network
services and operations through combining the packet experience of
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MPLS with the operational experience of SONET/SDH.
MPLS-TP will enable the migration of SONET/SDH networks to a packet-
based network that will easily scale to support packet services in a
simple and cost effective way. MPLS-TP needs to combine the
necessary existing capabilities of MPLS with additional minimal
mechanisms in order that it can be used in a transport role.
This document specifies the requirements for a MPLS Transport Profile
(MPLS-TP). This document is a product of a joint ITU-IETF effort to
include a MPLS Transport Profile within the IETF MPLS architecture to
support the capabilities and functionalities of a packet transport
network as defined by ITU-T.
This work is based on two sources of requirements, MPLS architecture
as defined by IETF and packet transport networks as defined by ITU-T.
The requirements of MPLS-TP are provided below.
Although both static and dynamic configuration of MPLS-TP transport
paths (including OAM and protection capabilities) is required by this
document, it MUST be possible for operators to be able to completely
operate (including OAM) an MPLS-TP network in the absence of any
control plane protocols for dynamic configuration.
1.1. Terminology
Section: A section is a network segment between two LSRs that are
immediately adjacent at the MPLS-TP layer.
Service layer: A network layer 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).
Tandem Connection: A tandem connection corresponds to a segment of a
path. This may be either a segment of an LSP (i.e. a sub-path), or
one or more segment(s) of a PW.
Transport path: A connection as define in G.805 [ITU.G805.2000].
Transport path layer: A network layer which provides point-to-point
or point-to-multipoint transport paths which are used to carry
aggregates of the network service layer.
Transmission media layer: A network layer which provides sections
(two-port point-to-point connections) to carry the aggregate of
network transport path or network service layers on various physical
media.
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1.2. Transport network overview
The connectivity service is the basic service provided by a transport
network. The purpose of a transport network is to transparently
carry its clients (i.e. the stream of client PDUs or client bits)
between endpoints in the network (typically over several intermediate
nodes). These endpoints may be service switching points or service
terminating points. The connectivity services offered to customers
are aggregated into large transport paths with long-holding times,
which enable the efficient and reliable operation of the transport
network. These transport paths are modified infrequently.
Aggregation and hierarchy are beneficial for achieving scalability
and security since:
1. They reduce the number of provisioning and forwarding states in
the network core.
2. They reduce load and the cost of implementing service assurance
and fault management.
3. Client signals are completely encapsulated and isolated from each
other. This also allows complete isolation of customer traffic
from carrier operations.
An important attribute of a transport network is its ability to
function independently from both its client and server (transmission
media) layer networks. It should be capable of transmitting over any
media. Another key characteristic of transport networks is the
capability to maintain the integrity of the client across the
transport network. A transport network must provide the means to
commit quality of service objectives to clients. This is achieved by
providing a mechanism for client network service demarcation for the
network path together with an associated network resiliency
mechanism. A transport network must also provide a method of service
monitoring in order to verify the delivery of an agreed quality of
service. This is enabled by means of carrier-grade OAM tools.
Client signals are first transparently encapsulated. These
encapsulated client signals are then aggregated for transport through
the network in order to optimize network management. Server layer
OAM is used to monitor the transport integrity of the client layer
aggregate. At any hop, the aggregated signals may be further
aggregated in lower layer transport network paths for transport
across intermediate shared links. The encapsulated client signals
are extracted at the edges of aggregation domains, and are either
delivered to the client or forwarded to another domain. In the core
of the network, only the server layer aggregated signals are
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monitored; individual client signals are monitored at the network
boundary in the client layer network.
Quality-of-service mechanisms are required in the packet transport
network to ensure the prioritization of critical services, to
guarantee BW and to control jitter and delay.
2. MPLS-TP Requirements
2.1. General requirements
o MPLS-TP MUST offer as much commonality as possible with the MPLS
data plane as defined by IETF. When MPLS offers multiple options
in this respect, MPLS-TP SHOULD select the minimum sub-set
(necessary and sufficient subset) applicable to a transport
network application.
o Any new functionality that is defined to fulfil the requirements
for MPLS-TP MUST be agreed within IETF and re-use (as far as
practically possible) existing MPLS standards.
o Mechanisms and capabilities MUST be able to interoperate with
existing IETF MPLS [RFC3031] and IETF PWE3 [RFC3985] control and
data planes where appropriate.
o MPLS-TP MUST support a connection-oriented packet switching
paradigm with traffic engineering capabilities that allow
deterministic control of the use of network resources.
o MPLS-TP MUST support the logical separation of the control and
management planes from the data plane.
o MPLS-TP MUST allow the physical separation of the control and
management planes from the data plane.
o MPLS-TP MUST support point to point (P2P) or point to multipoint
(P2MP) transport paths.
o MPLS-TP MUST support static provisioning of transport paths via an
NMS/OSS (i.e. via the management plane).
o Static provisioning MUST NOT depend on routing or signaling
protocols (e.g. GMPLS, OSPF, IS-IS, RSVP, BGP, LDP etc.).
o MPLS-TP MUST support the capability for network operation
(including OAM) via an NMS/OSS (without the use of any control
plane protocols).
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o MPLS-TP MUST support dynamic provisioning of transport paths via a
control plane.
o The MPLS-TP data plane MUST be capable of functioning
independently of the control or management plane used to operate
the MPLS-TP layer network. That is the MPLS-TP data plane
operation MUST continue to operate normally if the management
plane or control plane that configured the transport paths fails.
o MPLS-TP MUST support any network topology and be able to support
increasing bandwidth demands, topology, number of customers or
number of services incrementally.
o MPLS-TP SHOULD support mechanisms to safeguard against the
provisioning of transport paths which contain forwarding loops.
2.2. Layering requirements
o An MPLS-TP network MUST operate in a multiple layer network
environment consisting of independent service, transport path and
transmission media layers.
MPLS-TP may be used as the service layer (for P2P and P2MP services)
and/or as the transport path layer within a packet transport network.
o An MPLS-TP layer network MUST support the transparent transport of
MPLS-TP and non MPLS-TP client layer networks.
o An MPLS-TP layer network MUST be able to be transparently carried
over MPLS-TP and non MPLS-TP server layer networks (such as
Ethernet, OTN, etc.)
o It MUST be possible to operate the MPLS-TP layer network
independently of other layer networks (either MPLS-TP or non
MPLS-TP).
The above are not only technology requirements, but also operational.
Different administrative groups may be responsible for the same layer
network or different layer networks, and require the capability for
autonomous network operations.
o It MUST be possible to hide MPLS-TP layer network addressing and
other information (e.g. topology) from client layers.
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2.3. Data plane requirements
o The identification of each transport path within its aggregate
MUST be supported.
o A label in a particular section MUST uniquely identify the
transport path.
o A transport path's source MUST be identifiable at its destination.
Transport paths can be aggregated into trunks by pushing and de-
aggregated by popping labels. MPLS-TP labels are swapped within a
transport path in a layer network instance when the traffic is
forwarded from one MPLS-TP link to another MPLS-TP link.
o Labeling MUST make use of the MPLS label and label stack entry as
defined in RFC3032.
o It MUST be possible to operate and configure the MPLS-TP data
(transport) plane without any IP functionality.
o MPLS-TP MUST support both unidirectional and bi-directional point-
to-point transport paths.
o The forward and backward directions of a bi-directional transport
path MUST be capable of following the same path within the MPLS-TP
network.
o The intermediate nodes MUST be aware about the pairing
relationship of the forward and the backward directions belonging
to the same bi-directional transport path.
o MPLS-TP MUST support unidirectional point-to-multipoint transport
paths.
o MPLS-TP transport paths MUST NOT perform merging in a way that
prevents the unique identification of the source at the
destination (e.g. no use of LDP mp2p signaling in order to avoid
losing LSP head-end information, no use of PHP, etc).
o MPLS-TP MUST support transport paths through a single domain.
o MPLS-TP MUST support transport paths through multiple domains.
o MPLS-TP MUST be able to accommodate new traffic types.
o MPLS-TP SHOULD support mechanisms to minimize traffic impact
during network reconfiguration.
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o MPLS-TP SHOULD support mechanisms which ensure the integrity of
the transported customer's service traffic.
o MPLS-TP MUST support an unambiguous and reliable means of
distinguishing users' (client) packets from MPLS-TP control
packets (e.g. control plane, management plane, OAM and protection
switching packets).
2.4. Control plane requirements
o A distributed control plane MAY be supported to enable fast,
dynamic and reliable service provisioning in multi-vendor and
multi-domain environments using standardized protocols that
guarantee interoperability.
o If a control plane is used for configuration of MPLS-TP transport
paths then:
* Failure of the control plane MUST NOT impact the MPLS-TP data
plane.
* Recovery of the control plane MUST NOT impact the MPLS-TP data
plane any more than is necessary to re-establish the control
plane.
* It MUST support the setup, modification, and release of MPLS-TP
transport paths and protection paths.
* It MUST support mechanisms to provide traffic engineering,
constraint-based routing and explicit path control.
* It MUST provide mechanisms to address QoS and performance
requirements (such as throughput, delay, packet loss, etc.)
while utilizing network resources efficiently and reliably.
o MPLS-TP SHOULD support off-path (out-of-band) control and
management planes.
o The MPLS-TP control plane MUST be able to be operated independent
of any particular client or server layer control plane.
o The control plane SHOULD facilitate the implementation of the
service by providing end-to-end seamless connectivity and service
assurance.
o The MPLS-TP control plane MUST support establishing all the
connectivity patterns defined for the MPLS-TP data plane (e.g.,
uni-directional and bidirectional P2P, uni-directional P2MP, etc.)
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including configuration of protection functions and any associated
maintenance functions.
o The MPLS-TP control pane MUST support the configuration and
modification of OAM maintenance points as well as the activation/
deactivation of OAM when the transport path is established or
modified.
o An MPLS-TP control plane MUST support topology hiding and address
independence between domains.
o At the boundary of a domain an MPLS-TP control plane MUST support
unique control plane identifiers or addresses identifying boundary
points to be interconnected.
o At the boundary of a domain an MPLS-TP control plane MUST support
group control plane identifiers or addresses identifying sets of
boundary points to be interconnected.
o MPLS-TP data plane layer network access points (or connection
points that proxy for access points) SHOULD be able to be assigned
control plane identifiers which are available to clients to
identify endpoints in call or connection requests.
o An MPLS-TP control plane MUST support translation between
externally visible endpoint control plane identifiers and internal
network addresses.
o An MPLS-TP control plane MUST support constraint-based route
calculation.
o An MPLS-TP control plane MUST support provisioning and application
of routing constraint policies.
o An MPLS-TP control plane MUST support pre-provisioned path
protection.
In some situations it is impractical to expect acceptable recovery
performance to be achieved using dynamic recalculation of transport
path routes. For this reason, it is necessary to allow for pre-
planning of protection routes for selected transport paths.
o The MPLS-TP control plane MUST support fast restoration.
o An MPLS-TP control plane MUST scale gracefully to support a large
number of transport paths.
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o An MPLS-TP control plane MUST clearly distinguish resources
belonging to the MPLS-TP layer network from those in other layer
networks that may also be under control plane control.
o An MPLS-TP control plane MUST support the independent unique
identification of control plane elements as needed to support
interoperability.
o It MUST be possible to identify and provision these elements
independently, in order to reorganize the control plane components
without impacting the data plane services and vice-versa.
Architecturally distinct elements in a control plane include: nodes
and links, control plane functional components, protocol controllers,
etc.
o An MPLS-TP control plane SHOULD provide a common control mechanism
for architecturally similar operations.
o An MPLS-TP control plane MUST support mechanisms for partitioning
the network under control into separate peer or hierarchical
control domains.
o To enable the deployment of a unified control plane aimed at
controlling the set of transport technologies used in a transport
network, the MPLS-TP control plane MUST also be applicable to
other transport layer networks and provide common operations
across multiple layers. In order to maintain independence between
MPLS-TP and its respective client and server layer networks, the
capability to support separate control plane instances SHOULD be
possible for control of transport multilayer networks.
o MPLS-TP SHOULD detect and recover from control plane failures and
degradations using graceful operations.
2.5. Network Management (NM) requirements
o MPLS-TP MUST operate under a common operation, control and
management paradigm with respect to other transport technologies
(e.g. SDH, OTN or WDM).
o An MPLS-TP network MUST be able to be operated with a centralized
NMS system.
o An MPLS-TP network SHOULD be able to be operated by a centralized
NMS system with the support of a distributed control plane.
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o The MPLS-TP management plane MUST be able to operate independently
of any particular client or server layer management plane.
o The MPLS-TP management plane MUST support the configuration and
modification of OAM maintenance points as well as the activation/
deactivation of OAM when the transport path is established or
modified.
For the complete set of requirements related to NM functionality for
MPLS-TP, see the MPLS-TP NM requirements document [REF].
2.6. OAM requirements
o MPLS-TP SHOULD provide a comprehensive set of capabilities (that
are independent of and agnostic to the transmitted client
services) to support fault management (e.g. fault detection and
localization), performance monitoring (e.g. signal quality
measurement) of the MPLS-TP network and the services) and
protection switching.
o OAM mechanisms SHOULD detect and trigger recovery actions in case
of facility and equipment failures and performance degradations
according to the requirements of the service.
o MPLS-TP OAM and data MUST share the same fate.
o MPLS-TP OAM MUST be able to operate without IP functionality and
without relying on control and/or management planes. When MPLS-TP
is run with IP functionality, all existing IP-MPLS OAM
functionality, e.g. LSP-Ping, BFD and VCCV, MUST be able to
operate seamlessly.
For the complete set of requirements related to OAM functionality for
MPLS-TP, see the MPLS-TP OAM requirements document [REF].
2.7. Network performance management (PM) requirements
For the complete set of requirements related to PM functionality for
MPLS-TP, see the MPLS-TP OAM requirements document [REF].
2.8. Protection & Survivability requirements
Network survivability plays a critical factor in the delivery of
reliable services. Network availability is a significant contributor
to revenue and profit. Service guarantees in the form of SLAs
require a resilient network that rapidly detects facility or node
failures and restores network operation in accordance with the terms
of the SLA.
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The requirements in this section use the recovery terminology defined
in RFC 4427 [RFC4427].
o MPLS-TP MUST support transport network style protection switching
mechanisms (tandem network connection protection, LSP protection
and PW protection) to provide the appropriate recovery time
required to maintain customer SLAs when potentially thousands of
services are simultaneously affected by a single failure.
o MPLS-TP recovery mechanisms SHOULD be applicable at various levels
throughout the network including support for span, tandem
connection and end-to-end recovery.
o MPLS-TP MUST support network restoration mechanisms controlled by
a distributed control plane and MUST support network restoration
mechanisms controlled by a management plane.
* The restoration resources MAY be pre-planned and selected a
priori, or computed after failure occurrence.
* MPLS-TP MAY support shared-mesh restoration.
* MPLS-TP SHOULD support soft LSP restoration.
* MPLS-TP MAY support hard LSP restoration.
* The restoration mechanism MUST be applicable to any topology.
* Restoration priority MAY be implemented to determine the order
in which transport paths should be restored (to minimize
service restoration time as well as to gain access to available
spare capacity on the best paths). Preemption priority MAY be
used in the event that not all transport paths can be restored,
in which case transport paths with lower preemption priority
should be released. When preemption is supported, its use MUST
be operator configurable.
* The restoration mechanism SHOULD operate in synergy with other
transport network technologies (SDH, OTN, WDM).
o MPLS-TP MUST support data plane driven protection mechanisms
(without any dependency on a control plane or IP protocols) to
enable fast recovery from failure.
o If protection is supported then:
* MPLS-TP protection mechanisms SHOULD be applied to LSPs and
PWs.
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* MPLS-TP MUST support mechanisms that rapidly detect, locate,
notify and remedy network faults.
* MPLS-TP MAY support 1:1 bidirectional protection switching. If
bi-directional 1:1 protection switching is activated then the
protection state of both ends of the protected entity MUST be
synchronized.
* MPLS-TP MAY support 1+1 unidirectional protection switching.
* MPLS-TP protection mechanisms MUST be applicable to point-to-
point and SHOULD be applicable to point-to-multipoint transport
paths.
* Protection ratio MUST be of 100%, i.e. 100% of impaired working
traffic MUST be protected for a failure on the working path.
Additionally:
+ The QoS objectives defined by the operator MUST also be met
along the protection path.
+ In the case of 1:1 protection mechanisms, the bandwidth
reserved for the protection path MAY be available for other
traffic when the working path is operational.
* Operator requests for manual control of protection switching
such as clear, lockout of protection, forced-switch and manual-
switch commands MUST be supported. Prioritized protection
between Signal Fail (SF), Signal Degradation (SD) and operator
switch requests MUST be supported.
* MPLS-TP protection mechanisms MUST support revertive and non-
revertive behaviour.
* MPLS-TP protection switching mechanisms MUST prevent frequent
operation of the protection switch due to an intermittent
defect.
* MPLS-TP protection mechanisms MUST ensure co-ordination of
timing of protection switches at multiple layers to avoid races
and to allow the protection switching mechanism of the server
layer to fix the problem before switching at the MPLS-TP layer.
* MPLS-TP MAY support mechanisms that are optimized for specific
network topologies (Ring, Mesh) in order to handle protection
switching in an efficient manner.
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2.9. QoS requirements
Service providers require advanced traffic management capabilities to
enforce and guarantee the QoS parameters of customers' SLAs.
Quality of service mechanisms are required to ensure:
o Support for differentiated services and different traffic types
with traffic class separation associated with different traffic.
o Prioritization of critical services.
o Enabling the provisioning and the guarantee of Service Level
Specifications (SLS), with support for hard and relative end-to-
end BW guaranteed.
o Controlled jitter and delay.
o Guarantee of fair access to shared resources in an MPLS-TP
network.
o Resources for control and management plane packets so that data
plane traffic, regardless of the amount, will not cause control
and management functions to become inoperative.
MPLS-TP:
o MUST be able to deliver the same degree of QoS that has been
delivered by SDH/SONET systems.
o MUST support a method to offer packet loss objectives comparable
to those in TDM transport networks (only due to bit errors).
o SHOULD support transport and QoS mechanisms that can deliver
statistical multiplexing gain. Packets exceeding the agreed
traffic profile may be marked or discarded by the traffic
conditioning at the ingress of the MPLS-TP network.
o MUST support transport bandwidth allocation to any granularity
without any restrictions based on a circuit-switched multiplexing
hierarchy. This will provide service providers with the
capability to efficiently support service demands over the MPLS-TP
network.
[Should we refer here to the requirements specified in RFC 2702?]
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2.10. Security requirements
o MPLS-TP MUST ensure that the network and services are secured.
o Traffic flows from different users MUST NOT be intermingled, but
if this does occur then this MUST be detectable and the
appropriate consequent actions taken.
o MPLS-TP MUST ensure the separation of customer (client) and
provider (server and peer network) addressing and other
information.
o MPLS-TP MUST ensure that the control and management planes as well
as OAM traffic are secure from external attack.
o MPLS-TP MUST provide mechanisms to ensure that the MPLS-TP network
remains secure and stable under situations of extreme stress.
Examples of attacks and situations of extreme stress include (but are
not limited to) classical security attacks (e.g., hijacking, privacy,
non-repudiation, etc.) and attacks on network availability (e.g.,
denial of service (DoS) attacks).
3. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
4. Security Considerations
This document does not by itself raise any particular security
considerations.
5. Acknowledgements
The authors would like to thank all members of the teams (the Joint
Working Team, the MPLS Interoperability Design Team in IETF and the
T-MPLS Ad Hoc Group in ITU-T) involved in the definition and
specification of MPLS Transport Profile.
The authors would also like to thank Italo Busi, Neil Harrison,
Julien Meuric, Tom Nadeau, Hiroshi Ohta and Tomonori Takeda for their
comments and enhancements to the text.
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6. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4427] Mannie, E. and D. Papadimitriou, "Recovery (Protection and
Restoration) Terminology for Generalized Multi-Protocol
Label Switching (GMPLS)", RFC 4427, March 2006.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-
Edge (PWE3) Architecture", RFC 3985, March 2005.
[ITU.Y1401.2008]
International Telecommunications Union, "Principles of
interworking", ITU-T Recommendation Y.1401, February 2008.
[ITU.G805.2000]
International Telecommunications Union, "Generic
functional architecture of transport networks", ITU-
T Recommendation G.805, March 2000.
Authors' Addresses
Ben Niven-Jenkins (editor)
BT
208 Callisto House, Adastral Park
Ipswich, Suffolk IP5 3RE
UK
Email: benjamin.niven-jenkins@bt.com
Deborah Brungard (editor)
AT&T
Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748
USA
Email: dbrungard@att.com
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Malcolm Betts (editor)
Nortel Networks
3500 Carling Avenue
Ottawa, Ontario K2H 8E9
Canada
Email: betts01@nortel.com
Nurit Sprecher
Nokia Siemens Networks
3 Hanagar St. Neve Ne'eman B
Hod Hasharon, 45241
Israel
Email: nurit.sprecher@nsn.com
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