5.1. LDP Functions and Pseudowires
MPLS PWs are defined in [RFC3985] and [RFC5659], and provide for
emulated services over an MPLS Packet Switched Network (PSN).
Several types of PWs have been defined: (1) Ethernet PWs providing
for Ethernet port or Ethernet VLAN transport over MPLS [RFC4448], (2)
High-Level Data Link Control (HDLC) / PPP PW providing for HDLC/PPP
leased line transport over MPLS [RFC4618], (3) ATM PWs [RFC4816], (4)
Frame Relay PWs [RFC4619], and (5) circuit Emulation PWs [RFC4553].
Today's transport networks based on Plesiochronous Digital Hierarchy
(PDH), WDM, or SONET/SDH provide transport for PDH or SONET (e.g.,
ATM over SONET or Packet PPP over SONET) client signals with no
payload awareness. Implementing PW capability allows for the use of
an existing technology to substitute the Time-Division Multiplexing
(TDM) transport with packet-based transport, using well-defined PW
encapsulation methods for carrying various packet services over MPLS,
and providing for potentially better bandwidth utilization.
There are two general classes of PWs: (1) Single-Segment Pseudowires
(SS-PWs) [RFC3985] and (2) Multi-segment Pseudowires (MS-PWs)
[RFC5659]. An MPLS-TP network domain may transparently transport a
PW whose end points are within a client network. Alternatively, an
MPLS-TP edge node may be the Terminating PE (T-PE) for a PW,
performing adaptation from the native attachment circuit technology
(e.g., Ethernet 802.1Q) to an MPLS PW that is then transported in an
LSP over an MPLS-TP network. In this way, the PW is analogous to a
transport channel in a TDM network, and the LSP is equivalent to a
container of multiple non-concatenated channels, albeit they are
packet containers. An MPLS-TP network may also contain Switching PEs
(S-PEs) for a Multi-Segment PW whereby the T-PEs may be at the edge
of an MPLS-TP network or in a client network. In the latter case, a
T-PE in a client network performs the adaptation of the native
service to MPLS and the MPLS-TP network performs pseudowire
The SS-PW signaling control plane is based on targeted LDP (T-LDP)
with specific procedures defined in [RFC4447]. The MS-PW signaling
control plane is also based on T-LDP as allowed for in [RFC5659],
[RFC6073], and [MS-PW-DYNAMIC]. An MPLS-TP network shall use the
same PW signaling protocols and procedures for placing SS-PWs and
MS-PWs. This will leverage existing technology as well as facilitate
interoperability with client networks with native attachment circuits
or PW segments that are switched across an MPLS-TP network.
5.1.1. Management-Plane Support
There is no MPLS-TP requirement for a standardized management
interface to the MPLS-TP control plane. A general overview of MPLS-
TP-related MIB modules can be found in [TP-MIB]. Network management
requirements for MPLS-based transport networks are provided in
5.2. PW Control (LDP) and MPLS-TP Requirements Table
The following table shows how the MPLS-TP control-plane requirements
can be met using the existing LDP control plane for pseudowires
(targeted LDP). Areas where additional specifications are required
are also identified. The table lists references based on the
control-plane requirements as identified and numbered above in
In the table below, several of the requirements shown are addressed
-- in part or in full -- by the use of MPLS-TP LSPs to carry
pseudowires. This is reflected by including "TP-LSPs" as a reference
for those requirements. Section 5.3.2 provides additional context
for the binding of PWs to TP-LSPs.
5.3. Anticipated MPLS-TP-Related Extensions
Existing control protocol and procedures will be reused as much as
possible to support MPLS-TP. However, when using PWs in MPLS-TP, a
set of new requirements is defined that may require extensions of the
existing control mechanisms. This section clarifies the areas where
extensions are needed based on the requirements that are related to
the PW control plane and documented in [RFC5654].
Table 2 lists how requirements defined in [RFC5654] are expected to
The baseline requirement for extensions to support transport
applications is that any new mechanisms and capabilities must be able
to interoperate with existing IETF MPLS [RFC3031] and IETF PWE3
[RFC3985] control and data planes where appropriate. Hence,
extensions of the PW control plane must be in-line with the
procedures defined in [RFC4447], [RFC6073], and [MS-PW-DYNAMIC].
5.3.1. Extensions to Support Out-of-Band PW Control
For MPLS-TP, it is required that the data and control planes can be
both logically and physically separated. That is, the PW control
plane must be able to operate out-of-band (OOB). This separation
ensures, among other things, that in the case of control-plane
failures the data plane is not affected and can continue to operate
normally. This was not a design requirement for the current PW
control plane. However, due to the PW concept, i.e., PWs are
connecting logical entities ('forwarders'), and the operation of the
PW control protocol, i.e., only edge PE nodes (T-PE, S-PE) take part
in the signaling exchanges: moving T-LDP out-of-band seems to be,
theoretically, a straightforward exercise.
In fact, as a strictly local matter, ensuring that targeted LDP
(T-LDP) uses out-of-band signaling requires only that the local
implementation is configured in such a way that reachability for a
target LSR address is via the out-of-band channel.
More precisely, if IP addressing is used in the MPLS-TP control
plane, then T-LDP addressing can be maintained, although all
addresses will refer to control-plane entities. Both the PWid
Forwarding Equivalence Class (FEC) and Generalized PWid FEC Elements
can possibly be used in an OOB case as well. (Detailed evaluation is
outside the scope of this document.) The PW label allocation and
exchange mechanisms should be reused without change.
5.3.2. Support for Explicit Control of PW-to-LSP Binding
Binding a PW to an LSP, or PW segments to LSPs, is left to nodes
acting as T-PEs and S-PEs or a control-plane entity that may be the
same one signaling the PW. However, an extension of the PW signaling
protocol is required to allow the LSR at the signal initiation end to
inform the targeted LSR (at the signal termination end) to which LSP
the resulting PW is to be bound, in the event that more than one such
LSP exists and the choice of LSPs is important to the service being
setup (for example, if the service requires co-routed bidirectional
paths). This is also particularly important to support transport
path (symmetric and asymmetric) bandwidth requirements.
For transport services, MPLS-TP requires support for bidirectional
traffic that follows congruent paths. Currently, each direction of a
PW or a PW segment is bound to a unidirectional LSP that extends
between two T-PEs, two S-PEs, or a T-PE and an S-PE. The
unidirectional LSPs in both directions are not required to follow
congruent paths, and therefore both directions of a PW may not follow
congruent paths, i.e., they are associated bidirectional paths. The
only requirement in [RFC5659] is that a PW or a PW segment shares the
same T-PEs in both directions and the same S-PEs in both directions.
MPLS-TP imposes new requirements on the PW control plane, in
requiring that both end points map the PW or PW segment to the same
transport path for the case where this is an objective of the
service. When a bidirectional LSP is selected on one end to
transport the PW, a mechanism is needed that signals to the remote
end which LSP has been selected locally to transport the PW. This
would be accomplished by adding a new TLV to PW signaling.
Note that this coincides with the gap identified for OOB support: a
new mechanism is needed to allow explicit binding of a PW to the
supporting transport LSP.
The case of unidirectional transport paths may also require
additional protocol mechanisms, as today's PWs are always
bidirectional. One potential approach for providing a unidirectional
PW-based transport path is for the PW to associate different
(asymmetric) bandwidths in each direction, with a zero or minimal
bandwidth for the return path. This approach is consistent with
Section 3.8.2 of [RFC5921] but does not address P2MP paths.
5.3.3. Support for Dynamic Transfer of PW Control/Ownership
In order to satisfy requirement 47 (as defined in Section 2), it will
be necessary to specify methods for transfer of PW ownership from the
management to the control plane (and vice versa).
5.3.4. Interoperable Support for PW/LSP Resource Allocation
Transport applications may require resource guarantees. For such
transport LSPs, resource reservation mechanisms are provided via
RSVP-TE and the use of Diffserv. If multiple PWs are multiplexed
into the same transport LSP resources, contention may occur.
However, local policy at PEs should ensure proper resource sharing
among PWs mapped into a resource-guaranteed LSP. In the case of
MS-PWs, signaling carries the PW traffic parameters [MS-PW-DYNAMIC]
to enable admission control of a PW segment over a resource-
In conjunction with explicit PW-to-LSP binding, existing mechanisms
may be sufficient; however, this needs to be verified in detailed
5.3.5. Support for PW Protection and PW OAM Configuration
Many of the requirements listed in Section 2 are intended to support
connectivity and performance monitoring (grouped together as OAM), as
well as protection conformant with the transport services model.
In general, protection of MPLS-TP transported services is provided by
way of protection of transport LSPs. PW protection requires that
mechanisms be defined to support redundant pseudowires, including a
mechanism already described above for associating such pseudowires
with specific protected ("working" and "protection") LSPs. Also
required are definitions of local protection control functions, to
include test/verification operations, and protection status signals
needed to ensure that PW termination points are in agreement as to
which of a set of redundant pseudowires are in use for which
transport services at any given point in time.
Much of this work is currently being done in documents [PW-RED] and
[PW-REDB] that define, respectively, how to establish redundant
pseudowires and how to indicate which is in use. Additional work may
Protection switching may be triggered manually by the operator, or as
a result of loss of connectivity (detected using the mechanisms of
[RFC5085] and [RFC5586]), or service degradation (detected using
mechanisms yet to be defined).
Automated protection switching is just one of the functions for which
a transport service requires OAM. OAM is generally referred to as
either "proactive" or "on-demand", where the distinction is whether a
specific OAM tool is being used continuously over time (for the
purpose of detecting a need for protection switching, for example) or
is only used -- either a limited number of times or over a short
period of time -- when explicitly enabled (for diagnostics, for
PW OAM currently consists of connectivity verification defined by
[RFC5085]. Work is currently in progress to extend PW OAM to include
bidirectional forwarding detection (BFD) in [RFC5885], and work has
begun on extending BFD to include performance-related monitor
5.3.6. Client-Layer and Cross-Provider Interfaces to PW Control
Additional work is likely to be required to define consistent access
by a client-layer network, as well as between provider networks, to
control information available to each type of network, for example,
about the topology of an MS-PW. This information may be required by
the client-layer network in order to provide hints that may help to
avoid establishment of fate-sharing alternate paths. Such work will
need to fit within the ASON architecture; see requirement 38 above.
5.4. ASON Architecture Considerations
MPLS-TP PWs are always transported using LSPs, and these LSPs will
either have been statically provisioned or signaled using GMPLS.
For LSPs signaled using the MPLS-TP LSP control plane (GMPLS),
conformance with the ASON architecture is as described in Section 1.2
("Basic Approach"), bullet 4, of this framework document.
As discussed above in Section 5.3, there are anticipated extensions
in the following areas that may be related to ASON architecture:
- PW-to-LSP binding (Section 5.3.2)
- PW/LSP resource allocation (Section 5.3.4)
- PW protection and OAM configuration (Section 5.3.5)
- Client-layer interfaces for PW control (Section 5.3.6)
This work is expected to be consistent with ASON architecture and may
require additional specification in order to achieve this goal.
6. Security Considerations
This document primarily describes how existing mechanisms can be used
to meet the MPLS-TP control-plane requirements. The documents that
describe each mechanism contain their own security considerations
sections. For a general discussion on MPLS- and GMPLS-related
security issues, see the MPLS/GMPLS security framework [RFC5920]. As
mentioned above in Section 2.4, there are no specific MPLS-TP
control-plane security requirements.
This document also identifies a number of needed control-plane
extensions. It is expected that the documents that define such
extensions will also include any appropriate security considerations.
The authors would like to acknowledge the contributions of Yannick
Brehon, Diego Caviglia, Nic Neate, Dave Mcdysan, Dan Frost, and Eric
Osborne to this work. We also thank Dan Frost in his help responding
to Last Call comments.
8.1. Normative References
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.
[RFC2211] Wroclawski, J., "Specification of the Controlled-Load
Network Element Service", RFC 2211, September 1997.
[RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212, September
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
[RFC3478] Leelanivas, M., Rekhter, Y., and R. Aggarwal, "Graceful
Restart Mechanism for Label Distribution Protocol", RFC
3478, February 2003.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
[RFC4124] Le Faucheur, F., Ed., "Protocol Extensions for Support of
Diffserv-aware MPLS Traffic Engineering", RFC 4124, June
[RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
Extensions in Support of Generalized Multi-Protocol Label
Switching (GMPLS)", RFC 4202, October 2005.
[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, October 2005.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.
[RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
Use over an MPLS PSN", RFC 4385, February 2006.
[RFC4447] Martini, L., Ed., Rosen, E., El-Aawar, N., Smith, T., and
G. Heron, "Pseudowire Setup and Maintenance Using the
Label Distribution Protocol (LDP)", RFC 4447, April 2006.
[RFC4448] Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
"Encapsulation Methods for Transport of Ethernet over MPLS
Networks", RFC 4448, April 2006.
[RFC4842] Malis, A., Pate, P., Cohen, R., Ed., and D. Zelig,
"Synchronous Optical Network/Synchronous Digital Hierarchy
(SONET/SDH) Circuit Emulation over Packet (CEP)", RFC
4842, April 2007.
[RFC4863] Martini, L. and G. Swallow, "Wildcard Pseudowire Type",
RFC 4863, May 2007.
[RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
Ed., "RSVP-TE Extensions in Support of End-to-End
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery", RFC 4872, May 2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC4929] Andersson, L., Ed., and A. Farrel, Ed., "Change Process
for Multiprotocol Label Switching (MPLS) and Generalized
MPLS (GMPLS) Protocols and Procedures", BCP 129, RFC 4929,
[RFC4974] Papadimitriou, D. and A. Farrel, "Generalized MPLS (GMPLS)
RSVP-TE Signaling Extensions in Support of Calls", RFC
4974, August 2007.
[RFC5063] Satyanarayana, A., Ed., and R. Rahman, Ed., "Extensions to
GMPLS Resource Reservation Protocol (RSVP) Graceful
Restart", RFC 5063, October 2007.
[RFC5151] Farrel, A., Ed., Ayyangar, A., and JP. Vasseur, "Inter-
Domain MPLS and GMPLS Traffic Engineering -- Resource
Reservation Protocol-Traffic Engineering (RSVP-TE)
Extensions", RFC 5151, February 2008.
[RFC5287] Vainshtein, A. and Y(J). Stein, "Control Protocol
Extensions for the Setup of Time-Division Multiplexing
(TDM) Pseudowires in MPLS Networks", RFC 5287, August
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, October 2008.
[RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5316, December 2008.
[RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5392, January 2009.
[RFC5467] Berger, L., Takacs, A., Caviglia, D., Fedyk, D., and J.
Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
Switched Paths (LSPs)", RFC 5467, March 2009.
[RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed.,
"MPLS Generic Associated Channel", RFC 5586, June 2009.
[RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
Sprecher, N., and S. Ueno, "Requirements of an MPLS
Transport Profile", RFC 5654, September 2009.
[RFC5860] Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
"Requirements for Operations, Administration, and
Maintenance (OAM) in MPLS Transport Networks", RFC 5860,
[RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
L., and L. Berger, "A Framework for MPLS in Transport
Networks", RFC 5921, July 2010.
[RFC5960] Frost, D., Ed., Bryant, S., Ed., and M. Bocci, Ed., "MPLS
Transport Profile Data Plane Architecture", RFC 5960,
[RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
Profile (MPLS-TP) Identifiers", RFC 6370, September 2011.
[RFC6371] Busi, I., Ed., and D. Allan, Ed., "Operations,
Administration, and Maintenance Framework for MPLS-Based
Transport Networks", RFC 6371, September 2011.
[RFC6372] Sprecher, N., Ed., and A. Farrel, Ed., "MPLS Transport
Profile (MPLS-TP) Survivability Framework", RFC 6372,
8.2. Informative References
Bellagamba, E., Ed., Andersson, L., Ed., Skoldstrom, P.,
Ed., Ward, D., and A. Takacs, "Configuration of Pro-Active
Operations, Administration, and Maintenance (OAM)
Functions for MPLS-based Transport Networks using RSVP-
TE", Work in Progress, July 2011.
Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE
extensions for OAM Configuration", Work in Progress, July
[GMPLS-PS] Takacs, A., Fondelli, F., and B. Tremblay, "GMPLS RSVP-TE
Recovery Extension for data plane initiated reversion and
protection timer signalling", Work in Progress, April
International Telecommunication Union, "Architecture for
the automatically switched optical network (ASON)", ITU-T
Recommendation G.8080, June 2006.
International Telecommunication Union, "Architecture for
the automatically switched optical network (ASON)
Amendment 1", ITU-T Recommendation G.8080 Amendment 1,
Martini, L., Ed., Bocci, M., Ed., and F. Balus, Ed.,
"Dynamic Placement of Multi Segment Pseudowires", Work in
Progress, July 2011.
[NO-PHP] Ali, z., et al, "Non Penultimate Hop Popping Behavior and
out-of-band mapping for RSVP-TE Label Switched Paths",
Work in Progress, August 2011.
[PW-OAM] Zhang, F., Ed., Wu, B., Ed., and E. Bellagamba, Ed., "
Label Distribution Protocol Extensions for Proactive
Operations, Administration and Maintenance Configuration
of Dynamic MPLS Transport Profile PseudoWire", Work in
Progress, August 2011.
[PW-P2MPE] Aggarwal, R. and F. Jounay, "Point-to-Multipoint Pseudo-
Wire Encapsulation", Work in Progress, March 2010.
[PW-P2MPR] Jounay, F., Ed., Kamite, Y., Heron, G., and M. Bocci,
"Requirements and Framework for Point-to-Multipoint
Pseudowire", Work in Progress, July 2011.
[PW-RED] Muley, P., Ed., Aissaoui, M., Ed., and M. Bocci,
"Pseudowire Redundancy", Work in Progress, July 2011.
[PW-REDB] Muley, P., Ed., and M. Aissaoui, Ed., "Preferential
Forwarding Status Bit", Work in Progress, March 2011.
[RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
Protocol Label Switching (MPLS) Support of Differentiated
Services", RFC 3270, May 2002.
[RFC3468] Andersson, L. and G. Swallow, "The Multiprotocol Label
Switching (MPLS) Working Group decision on MPLS signaling
protocols", RFC 3468, February 2003.
[RFC3472] Ashwood-Smith, P., Ed., and L. Berger, Ed., "Generalized
Multi-Protocol Label Switching (GMPLS) Signaling
Constraint-based Routed Label Distribution Protocol (CR-
LDP) Extensions", RFC 3472, January 2003.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003.
[RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Traffic Engineering
(TE) Management Information Base (MIB)", RFC 3812, June
[RFC3813] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Label Switching
Router (LSR) Management Information Base (MIB)", RFC 3813,
[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.
[RFC3985] Bryant, S., Ed., and P. Pate, Ed., "Pseudo Wire Emulation
Edge-to-Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC4139] Papadimitriou, D., Drake, J., Ash, J., Farrel, A., and L.
Ong, "Requirements for Generalized MPLS (GMPLS) Signaling
Usage and Extensions for Automatically Switched Optical
Network (ASON)", RFC 4139, July 2005.
[RFC4201] Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
in MPLS Traffic Engineering (TE)", RFC 4201, October 2005.
[RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
"Generalized Multiprotocol Label Switching (GMPLS) User-
Network Interface (UNI): Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Support for the Overlay
Model", RFC 4208, October 2005.
[RFC4258] Brungard, D., Ed., "Requirements for Generalized Multi-
Protocol Label Switching (GMPLS) Routing for the
Automatically Switched Optical Network (ASON)", RFC 4258,
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
[RFC4426] Lang, J., Ed., Rajagopalan, B., Ed., and D. Papadimitriou,
Ed., "Generalized Multi-Protocol Label Switching (GMPLS)
Recovery Functional Specification", RFC 4426, March 2006.
[RFC4427] Mannie, E., Ed., and D. Papadimitriou, Ed., "Recovery
(Protection and Restoration) Terminology for Generalized
Multi-Protocol Label Switching (GMPLS)", RFC 4427, March
[RFC4553] Vainshtein, A., Ed., and YJ. Stein, Ed., "Structure-
Agnostic Time Division Multiplexing (TDM) over Packet
(SAToP)", RFC 4553, June 2006.
[RFC4618] Martini, L., Rosen, E., Heron, G., and A. Malis,
"Encapsulation Methods for Transport of PPP/High-Level
Data Link Control (HDLC) over MPLS Networks", RFC 4618,
[RFC4619] Martini, L., Ed., Kawa, C., Ed., and A. Malis, Ed.,
"Encapsulation Methods for Transport of Frame Relay over
Multiprotocol Label Switching (MPLS) Networks", RFC 4619,
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
[RFC4783] Berger, L., Ed., "GMPLS - Communication of Alarm
Information", RFC 4783, December 2006.
[RFC4802] Nadeau, T., Ed., and A. Farrel, Ed., "Generalized
Multiprotocol Label Switching (GMPLS) Traffic Engineering
Management Information Base", RFC 4802, February 2007.
[RFC4803] Nadeau, T., Ed., and A. Farrel, Ed., "Generalized
Multiprotocol Label Switching (GMPLS) Label Switching
Router (LSR) Management Information Base", RFC 4803,
[RFC4816] Malis, A., Martini, L., Brayley, J., and T. Walsh,
"Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous
Transfer Mode (ATM) Transparent Cell Transport Service",
RFC 4816, February 2007.
[RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
Yasukawa, Ed., "Extensions to Resource Reservation
Protocol - Traffic Engineering (RSVP-TE) for Point-to-
Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May
[RFC5003] Metz, C., Martini, L., Balus, F., and J. Sugimoto,
"Attachment Individual Identifier (AII) Types for
Aggregation", RFC 5003, September 2007.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, October 2007.
[RFC5085] Nadeau, T., Ed., and C. Pignataro, Ed., "Pseudowire
Virtual Circuit Connectivity Verification (VCCV): A
Control Channel for Pseudowires", RFC 5085, December 2007.
[RFC5145] Shiomoto, K., Ed., "Framework for MPLS-TE to GMPLS
Migration", RFC 5145, March 2008.
[RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
[RFC5493] Caviglia, D., Bramanti, D., Li, D., and D. McDysan,
"Requirements for the Conversion between Permanent
Connections and Switched Connections in a Generalized
Multiprotocol Label Switching (GMPLS) Network", RFC 5493,
[RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi-
Segment Pseudowire Emulation Edge-to-Edge", RFC 5659,
[RFC5787] Papadimitriou, D., "OSPFv2 Routing Protocols Extensions
for Automatically Switched Optical Network (ASON)
Routing", RFC 5787, March 2010.
[RFC5852] Caviglia, D., Ceccarelli, D., Bramanti, D., Li, D., and S.
Bardalai, "RSVP-TE Signaling Extension for LSP Handover
from the Management Plane to the Control Plane in a GMPLS-
Enabled Transport Network", RFC 5852, April 2010.
[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., Ed., and C. Pignataro, Ed., "Bidirectional
Forwarding Detection (BFD) for the Pseudowire Virtual
Circuit Connectivity Verification (VCCV)", RFC 5885, June
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[RFC5951] Lam, K., Mansfield, S., and E. Gray, "Network Management
Requirements for MPLS-based Transport Networks", RFC 5951,
[RFC6001] Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
Extensions for Multi-Layer and Multi-Region Networks
(MLN/MRN)", RFC 6001, October 2010.
[RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011.
[RFC6107] Shiomoto, K., Ed., and A. Farrel, Ed., "Procedures for
Dynamically Signaled Hierarchical Label Switched Paths",
RFC 6107, February 2011.
[RFC6215] Bocci, M., Levrau, L., and D. Frost, "MPLS Transport
Profile User-to-Network and Network-to-Network
Interfaces", RFC 6215, April 2011.
[TE-MIB] Miyazawa, M., Otani, T., Kumaki, K., and T. Nadeau,
"Traffic Engineering Database Management Information Base
in support of MPLS-TE/GMPLS", Work in Progress, July 2011.
[TP-MIB] King, D., Ed., and M. Venkatesan, Ed., "Multiprotocol
Label Switching Transport Profile (MPLS-TP) MIB-based
Management Overview", Work in Progress, August 2011.
Frost, D., Ed., Bocci, M., Ed., and L. Berger, Ed., "A
Framework for Point-to-Multipoint MPLS in Transport
Networks", Work in Progress, July 2011.
[TP-RING] Weingarten, Y., Ed., "MPLS-TP Ring Protection", Work in
Progress, June 2011
9. Contributing Authors
1. Laborc u.