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Versions: (draft-abfb-mpls-tp-control-plane-framework)
00 01 02 03 04 05 06 RFC 6373
Internet Draft Loa Andersson, Ed. (Ericsson)
Category: Informational Lou Berger, Ed. (LabN)
Expiration Date: December 18, 2010 Luyuan Fang, Ed. (Cisco)
Nabil Bitar, Ed. (Verizon)
June 18, 2010
MPLS-TP Control Plane Framework
draft-ietf-ccamp-mpls-tp-cp-framework-02.txt
Abstract
The MPLS Transport Profile (MPLS-TP) supports static provisioning
of transport paths via a Network Management System (NMS), and
dynamic provisioning of transport paths via a control plane. This
document provides the framework for MPLS-TP dynamic provisioning,
and covers control plane addressing, routing, path computation,
signaling, traffic engineering,, and path recovery. MPLS-TP uses
GMPLS as the control plane for MPLS-TP LSPs and provides for
compatibility with MPLS. MPLS-TP also uses the control plane for
Pseudowires (PWs). Management plane functions such as manual
configuration and the initiation of LSP setup are out of scope of
this document.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
This Internet-Draft will expire on December 18, 2010
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Copyright and License Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1 Introduction ........................................... 3
1.1 Conventions Used In This Document ...................... 3
1.2 Scope .................................................. 4
1.3 Basic Approach ......................................... 4
1.4 Reference Model ........................................ 5
2 Control Plane Requirements ............................. 8
2.1 Primary Requirements ................................... 8
2.2 MPLS-TP Framework Derived Requirements ................. 17
2.3 OAM Framework Derived Requirements ..................... 18
2.4 Security Requirements .................................. 21
3 Relationship of PWs and TE LSPs ........................ 21
4 TE LSPs ................................................ 22
4.1 GMPLS Functions and MPLS-TP LSPs ....................... 22
4.1.1 In-Band and Out-Of-Band Control and Management ......... 22
4.1.2 Addressing ............................................. 23
4.1.3 Routing ................................................ 23
4.1.4 TE LSPs and Constraint-Based Path Computation .......... 24
4.1.5 Signaling .............................................. 24
4.1.6 Unnumbered Links ....................................... 25
4.1.7 Link Bundling .......................................... 25
4.1.8 Hierarchical LSPs ...................................... 25
4.1.9 LSP Recovery ........................................... 26
4.1.10 Control Plane Reference Points (E-NNI, I-NNI, UNI) ..... 26
4.2 OAM, MEP (Hierarchy) Configuration and Control ......... 26
4.2.1 Management Plane Support ............................... 27
4.3 GMPLS and MPLS-TP Requirements Table ................... 28
4.4 Anticipated MPLS-TP Related Extensions and Definitions . 31
4.4.1 MPLS to MPLS-TP Interworking ........................... 31
4.4.2 Associated Bidirectional LSPs .......................... 31
4.4.3 Asymmetric Bandwidth LSPs .............................. 32
4.4.4 Recovery for P2MP LSPs ................................. 32
4.4.5 Test Traffic Control and other OAM functions ........... 32
4.4.6 DiffServ Object usage in GMPLS ......................... 32
5 Pseudowires ............................................ 33
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5.1 LDP Functions and Pseudowires .......................... 33
5.2 PW Control (LDP) and MPLS-TP Requirements Table ........ 34
5.3 Anticipated MPLS-TP Related Extensions ................. 36
5.3.1 Extensions to Support Out-of-Band PW Control ........... 37
5.3.2 Support for Explicit Control of PW-to-LSP Binding ...... 37
5.3.3 Support for Dynamic Transfer of PW Control/Ownership ... 38
5.3.4 Interoperable Support for PW/LSP Resource Allocation ... 38
5.3.5 Support for PW Protection and PW OAM Configuration ..... 39
5.3.6 Client Layer Interfaces to Pseudowire Control .......... 39
5.4 Pseudowire OAM and Recovery (Redundancy) ............... 39
6 Security Considerations ................................ 40
7 IANA Considerations .................................... 40
8 Acknowledgments ........................................ 40
9 References ............................................. 40
9.1 Normative References ................................... 40
9.2 Informative References ................................. 43
10 Authors' Addresses ..................................... 48
1. Introduction
The MPLS Transport Profile (MPLS-TP) is being defined in a joint
effort between the International Telecommunications Union (ITU) and
the IETF. The requirements for MPLS-TP are defined in the
requirements document, see [RFC5654]. These requirements state that
"A solution MUST be provided to support dynamic provisioning of MPLS-
TP transport paths via a control plane." This document provides the
framework for such dynamic provisioning.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunications Union Telecommunications
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functions of a packet transport network as defined
by the ITU-T.
1.1. Conventions Used In This Document
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].
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1.2. Scope
This document covers the control plane functions involved in
establishing MPLS-TP Label Switched Paths (LSPs) and Pseudowires
(PWs). The control plane requirements for MPLS-TP are defined in the
MPLS-TP requirements document [RFC5654]. These requirements define
the role of the control plane in MPLS-TP. In particular, Sections
2.4 and portions of the remainder of Section 2 of [RFC5654] provide
specific control plane requirements.
The LSPs provided by MPLS-TP are used as a server layer for IP, MPLS
and PWs, as well as other tunneled MPLS-TP LSPs. The PWs are used to
carry client signals other than IP or MPLS. The relationship between
PWs and MPLS-TP LSPs is exactly the same as between PWs and MPLS LSPs
in a Packet switched network (PSN). The PW encapsulation over MPLS-TP
LSPs used in MPLS-TP networks is also the same as for PWs over MPLS
in an MPLS network. MPLS-TP also defines protection and restoration
(or, collectively, recovery) functions. The MPLS-TP control plane
provides methods to establish, remove and control MPLS-TP LSPs and
PWs. This includes control of data plane, OAM and recovery
functions.
A general framework for MPLS-TP has been defined in [TP-FWK], and a
survivability framework for MPLS-TP has been defined in [TP-SURVIVE].
These document scope the approaches and protocols that will be used
as the foundation for MPLS-TP. Notably, Section 3.5 of [TP-FWK]
scopes the IETF protocols that serve as the foundation of the MPLS-TP
control plane. The PW control plane is based on the existing PW
control plane, see [RFC4447], and the PW end-to-end (PWE3)
architecture, see [RFC3985]. The LSP control plane is based on
Generalized MPLS (GMPLS), see [RFC3945], which is built on MPLS
Traffic Engineering (TE) and its numerous extensions. [TP-SURVIVE]
focuses on LSPs, and the protection functions that must be supported
within MPLS-TP. It does not specify which control plane mechanisms
are to be used.
The remainder of this document discusses the impact of MPLS-TP
requirements on the control of PWs as specified in [RFC4447],
[SEGMENTED-PW] and [MS-PW-DYNAMIC]. This document also discusses the
impact of the MPLS-TP requirements on the GMPLS signaling and routing
protocols that are used to control MPLS-TP LSPs.
1.3. Basic Approach
The basic approach taken in defining the MPLS-TP Control Plane
framework is:
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1) MPLS technology as defined by the IETF is the foundation for
the MPLS Transport Profile.
2) The data plane for MPLS and MPLS-TP is identical, i.e. any
extensions defined for MPLS-TP is also applicable to MPLS.
Additionally, the same encapsulation used for MPLS over any
layer 2 network is also used for MPLS-TP.
3) MPLS PWs are used as-is by MPLS-TP including the use of
targeted-LDP as the foundation for PW signaling [RFC4447],
OSPF-TE, ISIS-TE or MP-BGP as they apply for Multi-
Segment(MS)-PW routing. However, the PW can be encapsulated
over an MPLS-TP LSP (established using methods and procedures
for MPLS-TP LSP establishment) in addition to the presently
defined methods of carrying PWs over LSP based packet switched
networks (PSNs). That is, the MPLS-TP domain is a packet
switched network from a PWE3 architecture aspect [RFC3985].
4) The MPLS-TP LSP control plane builds on the GMPLS control plane
as defined by the IETF for transport LSPs. The protocols
within scope are RSVP-TE [RFC3473], OSPF-TE [RFC4203][RFC5392],
and ISIS-TE [RFC5307][RFC5316]. ASON/ASTN signaling and
routing requirements in the context of GMPLS can be found in
[RFC4139] and [RFC4258].
5) Existing IETF MPLS and GMPLS RFCs and evolving Working Group
Internet-Drafts should be reused wherever possible.
6) If needed, extensions for the MPLS-TP control plane should
first be based on the existing and evolving IETF work, secondly
based on work by other Standard bodies only when IETF decides
that the work is out of the IETF's scope. New extensions may be
defined otherwise.
7) Extensions to the GMPLS control plane may be required in order
to fully automate MPLS-TP functions.
8) Control-plane software upgrades to existing (G)MPLS enabled
equipment is acceptable and expected.
9) It is permissible for functions present in the GMPLS control
plane to not be used in MPLS-TP networks, e.g. the possibility
to merge LSPs.
10) One possible use of the control plane is to configure, enable
and empower OAM functionality. This will require extensions to
existing control plane specifications which will be usable in
MPLS-TP as well as MPLS networks.
11) MPLS-TP requirements are primarily defined in Section 2.4 and
relevant portions of the remainder Section 2 of [RFC5654].
1.4. Reference Model
The control plane reference model is based on the general MPLS-TP
reference model as defined in the MPLS-TP framework [TP-FWK]. Per the
MPLS-TP framework [TP-FWK], the MPLS-TP control plane is based on
GMPLS with RSVP-TE for LSP signaling and targeted LDP for PW
signaling. In both cases, OSPF-TE or ISIS-TE with GMPLS extensions
is used for dynamic routing within an MPLS-TP domain.
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From a service perspective, client interfaces are provided for both
the PWs and LSPs. PW client interfaces are defined on an interface
technology basis, e.g., Ethernet over PW [RFC4448]. In the context of
MPLS-TP LSP, the client interface is expected to be provided via a
GMPLS based UNI, see [RFC4208], or statically provisioned. As
discussed in [TP-FWK], MPLS-TP also presumes an LSP NNI reference
point.
The MPLS-TP end-to-end control plane reference model is shown in
Figure 1. The Figure shows the control plane protocols used by MPLS-
TP, as well as the UNI and NNI reference points.
|< ---- client signal (IP / MPLS / L2 / PW) ------------ >|
|< --------- SP1 ----------- >|< ------- SP2 ------- >|
|< ---------- MPLS-TP End-to-End PW ------------ >|
|< -------- MPLS-TP End-to-End LSP --------- >|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
|CE1|-|-|PE1|--|P1 |--|P2 |--|PE2|-|-|PEa|--|Pa |--|PEb|-|-|CE2|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
UNI NNI UNI
TE-RTG |< ---------------- >|< --- >|< ---------- >|
RSVP-TE
LDP |< --------------------------------------- >|
Figure 1. End-to-End MPLS-TP Control Plane Reference Model
Legend:
CE: Customer Edge
Client signal: defined in MPLS-TP Requirements
L2: Any layer 2 signal that may be carried
over a PW, e.g. Ethernet.
NNI: Network to Network Interface
PE: Provider Edge
SP: Service Provider
TE-RTG: OSPF-TE or ISIS-TE
UNI: User to Network Interface
Figure 2 adds three hierarchical LSP segments, labeled as "H-LSPs".
These segments are present to support scaling, OAM and MEPs within
each provider domain and across the inter-provider NNI. The MEPs are
used to collect performance information, support diagnostic
functions, and support OAM triggered survivability schemes as
discussed in [TP-SURVIVE]. Each H-LSP may be protected using any of
the schemes discussed in [TP-SURVIVE]. End-to-end monitoring is
supported via MEPs at the End-to-End LSP and PW end points. Note
that segment MEPs are collocated with MIPs of the next higher-layer
(e.g., end-to-end) LSPs.
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|< ------- client signal (IP / MPLS / L2 / PW) ------ >|
|< -------- SP1 ----------- >|< ------- SP2 ----- >|
|< ----------- MPLS-TP End-to-End PW -------- >|
|< ------- MPLS-TP End-to-End LSP ------- >|
|< -- H-LSP1 ---- >|<-H-LSP2->|<- H-LSP3 ->|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
|CE1|-|-|PE1|--|P1 |--|P2 |--|PE2|-|-|PEa|--|Pa |--|PEb|-|-|CE2|
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
UNI NNI UNI
..... ..... ..... .....
End2end |MEP|----------------|MIP|---|MIP|---------|MEP|
OAM ''''' ''''' ''''' '''''
..... ..... ..... ......... ......... ..... .....
Segment |MEP|-|MIP|-|MIP|-|MEP|MEP|-|MEP|MEP|-|MIP|-|MEP|
OAM ''''' ''''' ''''' ''''''''' ''''''''' ''''' '''''
Seg.TE-RTG|< -- >|< -- >|< -- >||< -- >||< -- >|< -- >|
RSVP-TE (within the MPLS-TP domain)
E2E TE-RTG|< ---------------- >|< ---- >|< --------- >|
RSVP-TE
LDP |< --------------------------------------- >|
Figure 2. MPLS-TP Control Plane Reference Model with OAM
Legend:
CE: Customer Edge
Client signal: defined in MPLS-TP Requirements
E2E: End-to-end
L2: Any layer 2 signal that may be carried
over a PW, e.g. Ethernet.
H-LSP: Hierarchical LSP
MEP: Maintenance end point
MIP: Maintenance intermediate point
NNI: Network to Network Interface
PE: Provider Edge
SP: Service Provider
TE-RTG: OSPF-TE or ISIS-TE
While not shown in the Figures above, it is worth noting that the
MPLS-TP control plane must support the addressing separation and
independence between the data, control and management planes as shown
in Figure 3 of [TP-FWK]. Address separation between the planes is
already included in GMPLS.
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2. Control Plane Requirements
The requirements for the MPLS-TP control plane are derived from the
MPLS-TP requirements and framework documents, specifically [RFC5654],
[TP-FWK], [RFC5860], [TP-OAM], and [TP-SURVIVE]. The requirements
are summarized in this section, but do not replace those documents.
If there are differences between this section and those documents,
those documents shall be considered authoritative.
2.1. Primary Requirements
These requirements are based on Section 2 [RFC5654]:
1. Any new functionality that is defined to fulfill the
requirements for MPLS-TP must be agreed within the IETF through
the IETF consensus process as per [RFC4929] [RFC5654, Section
1, Paragraph 15].
2. The MPLS-TP control plane design should as far as reasonably
possible reuse existing MPLS standards [RFC5654, requirement
2].
3. The MPLS-TP control plane must be able to interoperate with
existing IETF MPLS and PWE3 control planes where appropriate
[RFC5654, requirement 3].
4. The MPLS-TP control plane must be sufficiently well-defined to
ensure the interworking between equipment supplied by multiple
vendors will be possible both within a single domain and
between domains [RFC5654, requirement 4].
5. The MPLS-TP control plane must support a connection-oriented
packet switching model with traffic engineering capabilities
that allow deterministic control of the use of network
resources [RFC5654, requirement 5].
6. The MPLS-TP control plane must support traffic-engineered
point-to-point (P2P) and point-to-multipoint (P2MP) transport
paths [RFC5654, requirement 6].
7. The MPLS-TP control plane must support unidirectional,
associated bidirectional and co-routed bidirectional point-to-
point transport paths [RFC5654, requirement 7].
8. The MPLS-TP control plane must support unidirectional point-to-
multipoint transport paths [RFC5654, requirement 8].
9. All nodes (i.e., ingress, egress and intermediate) must be
aware about the pairing relationship of the forward and the
backward directions belonging to the same co-routed
bidirectional transport path [RFC5654, requirement 10].
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10. Edge nodes (i.e., ingress and egress) must be aware of the
pairing relationship of the forward and the backward directions
belonging to the same associated bidirectional transport path
[RFC5654, requirement 11].
11. Transit nodes should be aware of the pairing relationship of
the forward and the backward directions belonging to the same
associated bidirectional transport path [RFC5654, requirement
12].
12. The MPLS-TP control plane must support bidirectional transport
paths with symmetric bandwidth requirements, i.e. the amount of
reserved bandwidth is the same in the forward and backward
directions [RFC5654, requirement 13].
13. The MPLS-TP control plane must support bidirectional transport
paths with asymmetric bandwidth requirements, i.e. the amount
of reserved bandwidth differs in the forward and backward
directions [RFC5654, requirement 14].
14. The MPLS-TP control plane must support the logical separation
of the control and management planes from the data plane
[RFC5654, requirement 15]. Note that this implies that the
addresses used in the management, control and data planes are
independent.
15. The MPLS-TP control plane must support the physical separation
of the control and management planes from the data plane, and
no assumptions should be made about the state of the data-plane
channels from information about the control or management-plane
channels when they are running out-of-band [RFC5654,
requirement 16].
16. A control plane must be defined to support dynamic provisioning
and restoration of MPLS-TP transport paths, but its use is a
network operator's choice [RFC5654, requirement 18].
17. A control plane must not be required to support the static
provisioning of MPLS-TP transport paths. [RFC5654, requirement
19].
18. The MPLS-TP control plane must permit the coexistence of
statically and dynamically provisioned/managed MPLS-TP
transport paths within the same layer network or domain
[RFC5654, requirement 20].
19. The MPLS-TP control plane should be operable in a way that is
similar to the way the control plane operates in other
transport-layer technologies [RFC5654, requirement 21].
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20. The MPLS-TP control plane must avoid or minimize traffic impact
(e.g. packet delay, reordering and loss) during network
reconfiguration [RFC5654, requirement 24].
21. The MPLS-TP control plane must work across multiple homogeneous
domains [RFC5654, requirement 25].
22. The MPLS-TP control plane should work across multiple non-
homogeneous domains [RFC5654, requirement 26].
23. The MPLS-TP control plane must not dictate any particular
physical or logical topology [RFC5654, requirement 27].
24. The MPLS-TP control plane must include support of ring
topologies which may be deployed with arbitrarily
interconnection, support rings of at least 16 nodes [RFC5654,
requirement 27.A. and 27.B.].
25. The MPLS-TP control plane must scale gracefully to support a
large number of transport paths, nodes and links. That is it
must be able to scale at least as well as control planes in
existing transport technologies with growing and increasingly
complex network topologies as well as with increasing bandwidth
demands, number of customers, and number of services [RFC 5654,
requirements 53 and 28].
26. The MPLS-TP control plane should not provision transport paths
which contain forwarding loops [RFC5654, requirement 29].
27. The MPLS-TP control plane must support multiple client layers.
(e.g. MPLS-TP, IP, MPLS, Ethernet, ATM, FR, etc.) [RFC5654,
requirement 30].
28. The MPLS-TP control plane must provide a generic and extensible
solution to support the transport of MPLS-TP transport paths
over one or more server layer networks (such as MPLS-TP,
Ethernet, SONET/SDH, OTN, etc.). Requirements for bandwidth
management within a server layer network are outside the scope
of this document [RFC5654, requirement 31].
29. In an environment where an MPLS-TP layer network is supporting
a client layer network, and the MPLS-TP layer network is
supported by a server layer network then the control plane
operation of the MPLS-TP layer network must be possible without
any dependencies on the server or client layer network
[RFC5654, requirement 32].
30. The MPLS-TP control plane must allow for the transport of a
client MPLS or MPLS-TP layer network over a server MPLS or
MPLS-TP layer network [RFC5654, requirement 33].
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31. The MPLS-TP control plane must allow the operation the layers
of a multi-layer network that includes an MPLS-TP layer
autonomously [RFC5654, requirement 34].
32. The MPLS-TP control plane must allow the hiding of MPLS-TP
layer network addressing and other information (e.g. topology)
from client layer networks. However, it should be possible, at
the option of the operator, to leak a limited amount of
summarized information (such as SRLGs or reachability) between
layers [RFC5654, requirement 35].
33. The MPLS-TP control plane must allow for the identification of
a transport path on each link within and at the destination
(egress) of the transport network. [RFC5654, requirement 38 and
39].
34. The MPLS-TP control plane must allow for P2MP capable server
(sub-)layers [RFC5654, requirement 40].
35. The MPLS-TP control plane must be extensible in order to
accommodate new types of client layer networks and services
[RFC5654, requirement 41].
36. The MPLS-TP control plane should support the reserved bandwidth
associated with a transport path to be increased without
impacting the existing traffic on that transport path provided
enough resources are available [RFC5654, requirement 42].
37. The MPLS-TP control plane should support the reserved bandwidth
of a transport path to be decreased without impacting the
existing traffic on that transport path, provided that the
level of existing traffic is smaller than the reserved
bandwidth following the decrease [RFC5654, requirement 43].
38. The MPLS-TP control plane 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) [RFC5654, requirement
46].
39. The control plane for MPLS-TP must fit within the ASON
architecture. The ITU-T has defined an architecture for
Automatically Switched Optical Networks (ASON) in G.8080
[ITU.G8080.2006] and G.8080 Amendment 1 [ITU.G8080.2008]. An
interpretation of the ASON signaling and routing requirements
in the context of GMPLS can be found in [RFC4139] and [RFC4258]
[RFC5654, Section 2.4., Paragraph 2 and 3].
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40. The MPLS-TP control plane must support control plane topology
and data plane topology independence [RFC5654, requirement 47].
41. A failure of the MPLS-TP control plane must not interfere with
the deliver of service or recovery of established transport
paths [RFC5654, requirement 47].
42. The MPLS-TP control plane must be able to operate independent
of any particular client or server layer control plane
[RFC5654, requirement 48].
43. The MPLS-TP control plane should support, but not require, an
integrated control plane encompassing MPLS-TP together with its
server and client layer networks when these layer networks
belong to the same administrative domain [RFC5654, requirement
49].
44. The MPLS-TP control plane must support configuration of
protection functions and any associated maintenance (OAM)
functions [RFC5654, requirement 50 and 7].
45. The MPLS-TP control plane must support the configuration and
modification of OAM maintenance points as well as the
activation/deactivation of OAM when the transport path or
transport service is established or modified [RFC5654,
requirement 51].
46. The MPLS-TP control plane must be capable of restarting and
relearning its previous state without impacting forwarding
[RFC5654, requirement 54].
47. The MPLS-TP control plane must provide a mechanism for dynamic
ownership transfer of the control of MPLS-TP transport paths
from the management plane to the control plane and vice versa.
The number of reconfigurations required in the data plane must
be minimized (preferably no data plane reconfiguration will be
required) [RFC5654, requirement 55].
48. The MPLS-TP control plane must support protection and
restoration mechanisms, i.e., recovery [RFC5654, requirement
52].
Note that the MPLS-TP Survivability Framework document, [TP-
SURVIVE], provides additional useful information related to
recovery.
49. The MPLS-TP control plane mechanisms should be identical (or as
similar as possible) to those already used in existing
transport networks to simplify implementation and operations.
However, this must not override any other requirement [RFC5654,
requirement 56 A].
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50. The MPLS-TP control plane mechanisms used for P2P and P2MP
recovery should be identical to simplify implementation and
operation. However, this must not override any other
requirement [RFC5654, requirement 56 B].
51. The MPLS-TP control plane must support recovery mechanisms that
are applicable at various levels throughout the network
including support for link, transport path, segment,
concatenated segment and end-to-end recovery [RFC5654,
requirement 57].
52. The MPLS-TP control plane must support recovery paths that meet
the SLA protection objectives of the service [RFC5654,
requirement 58]. Including:
a. Guarantee 50ms recovery times from the moment of fault
detection in networks with spans less than 1200 km.
b. Protection of up to 100% of the traffic on the protected
path.
c. Recovery must meet SLA requirements over multiple
domains.
53. The MPLS-TP control plane should support per transport path
Recovery objectives [RFC5654, requirement 59].
54. The MPLS-TP control plane must support recovery mechanisms that
are applicable to any topology [RFC5654, requirement 60].
55. The MPLS-TP control plane must operate in synergy with
(including coordination of timing/timer settings) the recovery
mechanisms present in any client or server transport networks
(for example, Ethernet, SDH, OTN, WDM) to avoid race conditions
between the layers [RFC5654, requirement 61].
56. The MPLS-TP control plane must support recovery and reversion
mechanisms that prevent frequent operation of recovery in the
event of an intermittent defect [RFC5654, requirement 62].
57. The MPLS-TP control plane must support revertive and non-
revertive protection behavior [RFC5654, requirement 64].
58. The MPLS-TP control plane must support 1+1 bidirectional
protection for P2P transport paths [RFC5654, requirement 65 A].
59. The MPLS-TP control plane must support 1+1 unidirectional
protection for P2P transport paths [RFC5654, requirement 65 B].
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60. The MPLS-TP control plane must support 1+1 unidirectional
protection for P2MP transport paths [RFC5654, requirement 65
C].
61. The MPLS-TP control plane must support the ability to share
protection resources amongst a number of transport paths
[RFC5654, requirement 66].
62. The MPLS-TP control plane must support 1:n bidirectional
protection for P2P transport paths, and this should be the
default for 1:n protection [RFC5654, requirement 67 A].
63. The MPLS-TP control plane must support 1:n unidirectional
protection for P2MP transport paths [RFC5654, requirement 67
B].
64. The MPLS-TP control plane may support 1:n unidirectional
protection for P2P transport paths [RFC5654, requirement 65 C].
65. The MPLS-TP control plane may support extra-traffic [RFC5654,
note after requirement 67].
66. The MPLS-TP control plane should support 1:n (including 1:1)
shared mesh recovery [RFC5654, requirement 68].
67. The MPLS-TP control plane must support sharing of protection
resources such that protection paths that are known not to be
required concurrently can share the same resources [RFC5654,
requirement 69].
68. The MPLS-TP control plane must support the sharing of resources
between a restoration transport path and the transport path
being replaced [RFC5654, requirement 70].
69. The MPLS-TP control plane must support restoration priority so
that an implementation can determine the order in which
transport paths should be restored [RFC5654, requirement 71].
70. The MPLS-TP control plane must support preemption priority in
order to allow restoration to displace other transport paths in
the event of resource constraints [RFC5654, requirement 72 and
86].
71. The MPLS-TP control plane must support revertive and non-
revertive restoration behavior [RFC5654, requirement 73].
72. The MPLS-TP control plane must support recovery being triggered
by physical (lower) layer fault indications [RFC5654,
requirement 74].
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73. The MPLS-TP control plane must support recovery being triggered
by OAM [RFC5654, requirement 75].
74. The MPLS-TP control plane must support management plane
recovery triggers (e.g., forced switch, etc.) [RFC5654,
requirement 76].
75. The MPLS-TP control plane must support the differentiation of
administrative recovery actions from recovery actions initiated
by other triggers [RFC5654, requirement 77].
76. The MPLS-TP control plane should support control plane
restoration triggers (e.g., forced switch, etc.) [RFC5654,
requirement 78].
77. The MPLS-TP control plane must support priority logic to
negotiate and accommodate coexisting requests (i.e., multiple
requests) for protection switching (e.g., administrative
requests and requests due to link/node failures) [RFC5654,
requirement 79].
78. The MPLS-TP control plane must support the relationships of
protection paths and protection-to-working paths (sometimes
known as protection groups) [RFC5654, requirement 80].
79. The MPLS-TP control plane must support pre-calculation of
recovery paths [RFC5654, requirement 81].
80. The MPLS-TP control plane must support pre-provisioning of
recovery paths [RFC5654, requirement 82].
81. The MPLS-TP control plane must support the external commands
defined in [RFC4427]. External controls overruled by higher
priority requests (e.g., administrative requests and requests
due to link/node failures) or unable to be signaled to the
remote end (e.g. because of a protection state coordination
fail) must be ignored/dropped [RFC5654, requirement 83].
82. The MPLS-TP control plane must permit the testing and
validation of the integrity of the protection/recovery
transport path [RFC5654, requirement 84 A].
83. The MPLS-TP control plane must permit the testing and
validation of protection/ restoration mechanisms without
triggering the actual protection/restoration [RFC5654,
requirement 84 B].
84. The MPLS-TP control plane must permit the testing and
validation of protection/ restoration mechanisms while the
working path is in service [RFC5654, requirement 84 C].
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85. The MPLS-TP control plane must permit the testing and
validation of protection/ restoration mechanisms while the
working path is out of service [RFC5654, requirement 84 D].
86. The MPLS-TP control plane must support the establishment and
maintenance of all recovery entities and functions [RFC5654,
requirement 89 A].
87. The MPLS-TP control plane must support signaling of recovery
administrative control [RFC5654, requirement 89 B].
88. The MPLS-TP control plane must support protection state
coordination (PSC). Since control plane network topology is
independent from the data plane network topology, the PSC
supported by the MPLS-TP control plane may run on resources
different than the data plane resources handled within the
recovery mechanism (e.g. backup) [RFC5654, requirement 89 C].
89. When present, the MPLS-TP control plane must support recovery
mechanisms that are optimized for specific network topologies.
These mechanisms must be interoperable with the mechanisms
defined for arbitrary topology (mesh) networks to enable
protection of end-to-end transport paths [RFC5654, requirement
91].
90. When present, the MPLS-TP control plane must support the
control of ring topology specific recovery mechanisms [RFC5654,
Section 2.5.6.1].
91. The MPLS-TP control plane must include support for
differentiated services and different traffic types with
traffic class separation associated with different traffic
[RFC5654, requirement 110].
92. The MPLS-TP control plane must support the provisioning of
services that provide guaranteed Service Level Specifications
(SLS), with support for hard ([RFC3209] style) and relative
([RFC3270] style) end-to-end bandwidth guarantees [RFC5654,
requirement 111].
93. The MPLS-TP control plane must support the provisioning of
services which are sensitive to jitter and delay [RFC5654,
requirement 112].
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2.2. MPLS-TP Framework Derived Requirements
The following additional requirements are based on [TP-FWK], [TP-
P2MP-FWK] and [TP-DATA]:
94. Per-packet equal cost multi-path (ECMP) load balancing is not
applicable to MPLS-TP [TP-DATA-PLANE , section 3.1.1.,
paragraph 6].
95. Penultimate hop popping (PHP) is disabled on MPLS-TP LSPs by
default. The applicability of PHP to both MPLS-TP LSPs and MPLS
networks generally providing packet transport services will be
clarified in a future version [TP-DATA-PLANE , section 3.1.1.,
paragraph 7].
96. The MPLS-TP control plane must support both E-LSP and L-LSP
MPLS DiffServ modes as specified in [RFC3270] [TP-DATA-PLANE ,
section 3.3.2., paragraph 12].
97. Both single-segment and multi-segment PWs shall be supported by
the MPLS-TP control plane. MPLS-TP shall use the definition of
multi-segment PWs as defined by the IETF [TP-FWK, section
3.4.4.].
98. The MPLS-TP control plane must support the control of PWs and
their associated labels [TP-FWK, section 3.4.4.].
99. The MPLS-TP control plane must support network layer clients,
i.e., clients whose traffic is transported over an MPLS-TP
network without the use of PWs [TP-FWK, section 3.4.5.].
a. The MPLS-TP control plane must support the use of network
layer protocol-specific LSPs and labels. [TP-FWK, section
3.4.5.]
b. The MPLS-TP control plane must support the use of a
client service-specific LSPs and labels. [TP-FWK, section
3.4.5.]
100. The MPLS-TP control plane is based on the GMPLS control plane
for MPLS-TP LSPs. More specifically, GMPLS RSVP-TE [RFC3473]
and related extensions are used for LSP signaling, and GMPLS
OSPF-TE [RFC5392] and ISIS-TE [RFC5316] are used for routing
[TP-FWK, section 3.9.].
101. The MPLS-TP control plane is based on the MPLS control plane
for PWs, and more specifically, Targeted LDP (T-LDP) [RFC4447]
is used for PW signaling [TP-FWK, section 3.9., paragraph 5].
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102. Requirement intentionally blank.
103. The MPLS-TP control plane must ensure its own survivability and
to enable it to recover gracefully from failures and
degradations. These include graceful restart and hot redundant
configurations [TP-FWK, section 3.9., paragraph 16].
104. The MPLS-TP control plane must support linear, ring and meshed
protection schemes [TP-FWK, section 3.12., paragraph 3].
2.3. OAM Framework Derived Requirements
The following additional requirements are based on [RFC5860] and [TP-
OAM]:
105. The MPLS-TP control plane must support the capability to
enable/disable OAM functions as part of service establishment
[RFC5860, section 2.1.6., paragraph 1].
106. The MPLS-TP control plane must support the capability to
enable/disable OAM functions after service establishment. In
such cases, the customer must not perceive service degradation
as a result of OAM enabling/disabling [RFC5860, section 2.1.6.,
paragraph 1 and 2].
107. The MPLS-TP control plane must allow for the IP/MPLS and PW OAM
protocols (e.g., LSP-Ping [RFC4379], MPLS-BFD [RFC5884], VCCV
[RFC5085] and VCCV-BFD [RFC5885]) [RFC5860, section 2.1.4.,
paragraph 2].
108. The MPLS-TP control plane must allow for the ability to support
experimental OAM functions. These functions must be disabled
by default [RFC5860, section 2.2., paragraph 2].
109. The MPLS-TP control plane must support the choice of which (if
any) OAM function(s) to use and to which PW, LSP or Section it
applies [RFC5860, section 2.2., paragraph 3].
110. The MPLS-TP control plane must provide a mechanism to support
the localization of faults and the notification of appropriate
nodes. Such notification should trigger corrective (recovery)
actions [RFC5860, section 2.2.1., paragraph 1].
111. The MPLS-TP control plane must allow the service provider to be
informed of a fault or defect affecting the service(s) it
provides, even if the fault or defect is located outside of his
domain [RFC5860, section 2.2.1., paragraph 2].
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112. Information exchange between various nodes involved in the
MPLS-TP control plane should be reliable such that, for
example, defects or faults are properly detected or that state
changes are effectively known by the appropriate nodes
[RFC5860, section 2.2.1., paragraph 3].
113. The MPLS-TP control plane must provide functionality to control
an End Point to monitor the liveness, i.e., continuity check
(CC), of a PW, LSP or Section [RFC5860, section 2.2.2.,
paragraph 1].
114. The MPLS-TP control plane must provide functionality to control
an End Point's ability to determine, whether or not it is
connected to specific End Point(s), i.e., connectivity
verification (CV), by means of the expected PW, LSP or Section
[RFC5860, section 2.2.3., paragraph 1].
115. The MPLS-TP control plane must provide functionality to control
diagnostic testing on a PW, LSP or Section [RFC5860, section
2.2.5., paragraph 1].
116. The MPLS-TP control plane must provide functionality to enable
an End Point to discover the Intermediate (if any) and End
Point(s) along a PW, LSP or Section, and more generally to
trace (record) the route of a PW, LSP or Section [RFC5860,
section 2.2.4., paragraph 1].
117. The MPLS-TP control plane must provide functionality to enable
an End Point of a PW, LSP or Section to instruct its associated
End Point(s) to lock the PW, LSP or Section. Note that lock
corresponds to an administrative status in which it is expected
that only test traffic, if any, and OAM (dedicated to the PW,
LSP or Section) can be mapped on that PW, LSP or Section
[RFC5860, section 2.2.6., paragraph 1].
118. The MPLS-TP control plane must provide functionality to enable
an Intermediate Point of a PW or LSP to report, to an End Point
of that same PW or LSP, a lock condition indirectly affecting
that PW or LSP [RFC5860, section 2.2.7., paragraph 1].
119. The MPLS-TP control plane must provide functionality to enable
an Intermediate Point of a PW or LSP to report, to an End Point
of that same PW or LSP, a fault or defect condition affecting
that PW or LSP [RFC5860, section 2.2.8., paragraph 1].
120. The MPLS-TP control plane must provide functionality to enable
an End Point to report, to its associated End Point, a fault or
defect condition that it detects on a PW, LSP or Section for
which they are the End Points [RFC5860, section 2.2.9.,
paragraph 1].
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121. The MPLS-TP control plane must provide functionality to enable
the propagation, across an MPLS-TP network, of information
pertaining to a client defect or fault condition detected at an
End Point of a PW or LSP, if the client layer mechanisms do not
provide an alarm notification/propagation mechanism [RFC5860,
section 2.2.10., paragraph 1].
122. The MPLS-TP control plane must provide functionality to enable
the control of quantification of packet loss ratio over a PW,
LSP or Section [RFC5860, section 2.2.11., paragraph 1].
123. The MPLS-TP control plane must provide functionality to control
the quantification and reporting of the one-way, and if
appropriate, the two-way, delay of a PW, LSP or Section
[RFC5860, section 2.2.12., paragraph 1].
124. The MPLS-TP control plane must support the configuration of
MEPs.
a. The CC and CV functions operate between MEPs [TP-OAM,
section 5.1., paragraph 3].
b. All OAM packets coming to a MEP source are tunneled via
label stacking, and therefore a MEP can only exist at the
beginning and end of an LSP (i.e. at an LSP's ingress and
egress nodes and never at an LSP's transit node) [TP-OAM,
section 3.2., paragraph 10].
c. The CC and CV functions may serve as a trigger for
protection switching, see requirement 45 above.
d. This implies that LSP hierarchy must be used in cases
where OAM is used to trigger recovery when the recover
occurs at points other than an LSPs endpoints. [TP-OAM,
section 4., paragraph 5].
125. The MPLS-TP control plane must support the signaling of the MEP
identifier used in CC and CV [TP-OAM, section 5.1., paragraph
4].
126. The MPLS-TP control plane must support the signaling of the
transmission period used in CC and CV [TP-OAM, section 5.1.,
paragraph 6].
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2.4. Security Requirements
There are no specific MPLS-TP control plane security requirements.
The existing framework for MPLS and GMPLS security is documented on
[MPLS-SEC] and that document applies equally to MPLS-TP.
3. Relationship of PWs and TE LSPs
The data plane relationship between PWs and LSPs is inherited from
standard MPLS and is reviewed in the MPLS-TP Framework [TP-FWK].
Likewise, the control plane relationship between PWs and LSPs is
inherited from standard MPLS. This relationship is reviewed in this
document. The relationship between the PW and LSP control planes in
MPLS-TP is the same as the relationship found in the PWE3 Maintenance
Reference Model as presented in the PWE3 Architecture, see Figure 6
of [RFC3985]. The PWE3 Architecture [RFC3985] states: "the PWE3
protocol-layering model is intended to minimize the differences
between PWs operating over different PSN types." Additionally, PW
control (maintenance) takes place separately from LSP tunnel
signaling. [RFC3985] does allow for the extension of the (LSP)
tunnel control plane to exchange information necessary to support
PWs. [RFC4447] and [MS-PW-DYNAMIC] provide such extensions for the
use of LDP as the control plane for PWs. This control can provide PW
control without providing LSP control.
In the context of MPLS-TP, LSP tunnel signaling is provided via GMPLS
RSVP-TE. While RSVP-TE could be extended to support PW control much
as LDP was extended in [RFC4447], such extensions are out of scope of
this document. This means that the control of PWs and LSPs will
operate largely independently. The main coordination between LSP and
PW control will occur within the nodes that terminate PWs, or PW
segments. See Section 5.3.2 for an additional discussion on such
coordination.
It is worth noting that the control planes for PWs and LSPs may be
used independently, and that one may be employed without the other.
This translates into the four possible scenarios: (1) no control
plane is employed; (2) a control plane is used for both LSPs and PWs;
(3) a control plane is used for LSPs, but not PWs; (4) a control
plane is used for PWs, but not LSPs.
The PW and LSP control planes, collectively, must satisfy the MPLS-TP
control plane requirements reviewed in this document. When client
services are provided directly via LSPs, all requirements must be
satisfied by the LSP control plane. When client services are
provided via PWs, the PW and LSP control planes operate in
combination and some functions may be satisfied via the PW control
plane while others are provided to PWs by the LSP control plane. For
example, to support the recovery functions described in [TP-SURVIVE]
this document focuses on the control of the recovery functions at the
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LSP layer. PW based recovery is under development at this time and
may be used once defined.
4. TE LSPs
MPLS-TP LSPs are controlled via Generalized MPLS (GMPLS) signaling
and routing, see [RFC3945]. The GMPLS control plane is based on the
MPLS control plane. GMPLS includes support for MPLS labeled data and
transport data planes. GMPLS includes most of the transport centric
features required to support MPLS-TP LSPs. This section will first
review the MPLS-TP LSP relevant features of GMPLS, then identify how
specific requirements can be met using existing GMPLS functions and
will conclude with extensions that are anticipated to support MPLS-
TP.
4.1. GMPLS Functions and MPLS-TP LSPs
This section reviews how existing GMPLS functions can be applied to
MPLS-TP.
4.1.1. In-Band and Out-Of-Band Control and Management
GMPLS supports both in-band and out-of-band control. The terms in-
band and out-of-band typically refer to the relationship of the
management and control planes relative to the data plane. The terms
may be used to refer to the management plane independent of the
control plane, or to both of them in concert. There are multiple
uses of both terms in-band and out-of-band. The terms may relate to
a channel, a path or a network. Each of these can be used
independently or in combination. Briefly, some typical usage of the
terms are as follows:
o In-band
This term is used to refer to cases where management and/or
control plane traffic is sent using or embedded in the same
communication channel used to transport the associated data. IP,
MPLS, and Ethernet networks are all examples where control
traffic is typically sent in-band with the data traffic.
o Out-of-band, in-fiber
This term is used to refer to cases where management and/or
control plane traffic is sent using a different communication
channel from the associated data traffic, and the
control/management communication channel resides in the same
fiber as the data traffic. Optical transport networks typically
operate in an out-of-band in-fiber configuration.
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o Out-of-band, aligned topology
This term is used to refer to the cases where management and/or
control plane traffic is sent using a different communication
channel from the associated data traffic, and the
control/management communication must follow the same node-to-
node path as the data traffic. Such topologies are usually
supported using a parallel fiber or other configurations where
multiple data channels are available and one is (dynamically)
selected as the control channel.
o Out-of-band, independent topology
This term is used to refer to the cases where management and/or
control plane traffic is sent using a different communication
channel from the associated data traffic, and the
control/management communication may follow a path that is
completely independent of the data traffic. Such configurations
do not preclude the use of in-fiber or aligned topology links,
but alignment is not required.
In the context of MPLS-TP, requirement 14 (see Section 2 above) can
be met using out-of-band in-fiber or aligned topology types of
control. Requirement 15 can only be met by using Out-of-band,
independent topology. GMPLS routing and signaling can be used to
support in-band and all of the out-of-band forms of control, see
[RFC3945].
4.1.2. Addressing
MPLS-TP reuses and supports the addressing mechanisms supported by
MPLS. MPLS, and consequently, MPLS-TP uses the IPv4 and IPv6 address
families to identify MPLS-TP nodes by default for network management
and signaling purposes. The control, management and data planes used
in an MPLS-TP network may be completely separated or combined at the
discretion of an MPLS-TP operator and based on the equipment
capabilities of a vendor. The separation of the control and
management planes from the data plane allows each plane to be
independently addressable. Each plane may use addresses that are not
mutually reachable, e.g., it is likely that the data plane will not
be able to reach an address from the management or control planes and
vice versa. Each plane may also use a different address family. It
is even possible to reuse addresses in each plane, but this is not
recommended as it may lead to operational confusion.
4.1.3. Routing
Routing support for MPLS-TP LSPs is based on GMPLS routing. GMPLS
routing builds on TE routing and has been extended to support
multiple switching technologies per [RFC3945] and [RFC4202] as well
as multiple levels of packet switching (PSC) within a single network.
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IS-IS extensions for GMPLS are defined in [RFC5307] and [RFC5316],
which build on the TE extensions to IS-IS defined in [RFC5305]. OSPF
extensions for GMPLS are defined in [RFC4203] and [RFC5392], which
build on the TE extensions to OSPF defined in [RFC3630]. The listed
RFCs should be viewed as a starting point rather than an
comprehensive list as there are other IS-IS and OSPF extensions, as
defined in IETF RFCs, that can be used within an MPLS-TP network.
4.1.4. TE LSPs and Constraint-Based Path Computation
Both MPLS and GMPLS allow for traffic engineering and constraint-
based path computation. MPLS path computation provides paths for
MPLS TE unidirectional P2P and P2MP LSPs. GMPLS path computation
adds bidirectional LSPs, explicit recovery path computation as well
as support for the other functions discussed in this section.
Both MPLS and GMPLS path computation allow for the restriction of
path selection based on the use of Explicit Route Objects (EROs) and
other LSP attributes, see [RFC3209] and [RFC3473]. In all cases, no
specific algorithm is standardized by the IETF. This is anticipated
to continue to be the case for MPLS-TP LSPs.
4.1.4.1. Relation to PCE
Path Computation Element (PCE) Based approaches, see [RFC4655], may
be used for path computation of a GMPLS LSP, and consequently an
MPLS-TP LSP, across domains and in a single domain. In cases where
the architecture is used, the PCE Communication Protocol (PCECP), see
[RFC5440], will be used to communicate PCE requests and responses.
MPLS-TP specific extensions to PCECP are currently out of scope of
the MPLS-TP project and this document.
4.1.5. Signaling
GMPLS signaling is defined in [RFC3471] and [RFC3473], and is based
on RSVP-TE [RFC3209]. CR-LDP based GMPLS, [RFC3472] is no longer
under active development within the IETF, i.e., is deprecated, and
must not be used for MPLS-TP. In general, all RSVP-TE extensions
that apply to MPLS may also be used for GMPLS and consequently MPLS-
TP. Most notably this includes support for P2MP signaling as defined
in [RFC4875].
GMPLS signaling includes a number of MPLS-TP required functions.
Notably support for out-of-band control, bidirectional LSPs, and
independent control and data plane fault management. There are also
numerous other GMPLS and MPLS extensions that can be used to provide
specific functions in MPLS-TP networks. Specific references are
provided below.
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4.1.6. Unnumbered Links
Support for unnumbered links (i.e., links that do not have IP
addresses) is permitted in MPLS-TP and its usage is at the discretion
of the network operator. Support for unnumbered links is included
for routing in [RFC4203] for OSPF and [RFC5307] for IS-IS, and for
signaling in [RFC3477].
4.1.7. Link Bundling
Link bundling provides a local construct that can be used to improve
scaling of TE routing when multiple data links are shared between
node pairs. Link bundling for MPLS and GMPLS networks is defined in
[RFC4201]. Link bundling may be used in MPLS-TP networks and its use
is at the discretion of the network operator.
4.1.8. Hierarchical LSPs
This section reuses text from [HIERARCHY-BIS].
[RFC3031] describes how MPLS labels may be stacked so that LSPs may
be nested with one LSP running through another. This concept of
Hierarchical LSPs is formalized in [RFC4206] with a set of protocol
mechanisms for the establishment of a hierarchical LSP that can carry
one or more other LSPs.
[RFC4206] goes on to explain that a hierarchical LSP may carry other
LSPs only according to their switching types. This is a function of
the way labels are carried. In a packet switch capable (PSC) network,
the hierarchical LSP can carry other PSC LSPs using the MPLS label
stack.
Signaling mechanisms defined in [RFC4206] allow a hierarchical LSP to
be treated as a single hop in the path of another LSP. This mechanism
is known as "non-adjacent signaling."
A Forwarding Adjacency (FA) is defined in [RFC4206] as a data link
created from an LSP and advertised in the same instance of the
control plane that advertises the TE links from which the LSP is
constructed. The LSP itself is called an FA-LSP.
Thus, a hierarchical LSP may form an FA such that it is advertised as
a TE link in the same instance of the routing protocol as was used to
advertise the TE links that the LSP traverses.
As observed in [RFC4206] the nodes at the ends of an FA would not
usually have a routing adjacency.
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4.1.9. LSP Recovery
GMPLS defines RSVP-TE extensions in support for end-to-end GMPLS LSPs
recovery in [RFC4872], and segment recovery in [RFC4873] . GMPLS
segment recovery provides a superset of the function in end-to-end
recovery. End-to-end recovery can be viewed as a special case of
segment recovery where there is a single recovery domain whose
borders coincide with the ingress and egress of the LSP, although
specific procedures are defined.
The five defined types of recovery defined in MPLS-TP are:
- 1+1 bidirectional protection for P2P LSPs
- 1+1 unidirectional protection for P2MP LSPs
- 1:n (including 1:1) protection with or without extra traffic
- Rerouting without extra traffic (sometimes known as soft
rerouting), including shared mesh restoration
- Full LSP rerouting
Recovery for MPLS-TP LSPs is signaled using the mechanism defined in
[RFC4872] and [RFC4873]. Note that when MEPs are required for the
OAM CC function and the MEPs exists at LSP transit nodes, each MEP is
instantiated at a hierarchical LSP end point, and protection is
provided end-to-end for the hierarchical LSP. (Protection can be
signaled using either [RFC4872] and [RFC4873] defined procedures.)
The use of Notify messages to trigger protection switching and
recovery is not required in MPLS-TP as this function is expected to
be supported via OAM. However, it's use is not precluded.
4.1.10. Control Plane Reference Points (E-NNI, I-NNI, UNI)
The majority of GMPLS control plane related RFCs define the control
plane from the context of an internal network-to-network interface
(I-NNI). In the MPLS-TP context, some operators may choose to deploy
signaled interfaces across user-to-network (UNI) interfaces and
across inter-provider, external network-to-network (E-NNI),
interfaces. Such support is embodied in [RFC4208] for UNIs and
[RFC5787] for routing areas in support of E-NNIs. This work may
require extensions in order to meet the specific needs of an MPLS-TP
UNI and E-NNI.
4.2. OAM, MEP (Hierarchy) Configuration and Control
MPLS-TP is being defined to support a comprehensive set of MPLS-TP
OAM functions. Specific OAM requirements for MPLS-TP are documented
in [RFC5860]. In addition to the actual OAM requirements, it is also
required that the control plane be able to configure and control OAM
entities. This requirement is not yet addressed by the existing RFCs,
but such work is now underway, e.g., [CCAMP-OAM-FWK] and [CCAMP-OAM-
EXT].
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Many OAM functions occur on a per-LSP basis, are typically in-band,
and are initiated immediately after LSP establishment. Hence, it is
desirable that OAM is setup together with the establishment of the
data path (i.e., with the same signaling). This way OAM setup is
bound to connection establishment signaling, avoiding two separate
management/configuration steps (connection setup followed by OAM
configuration) which would increases delay, processing and more
importantly may be prune to misconfiguration errors.
It must be noted that although the control plane is used to establish
OAM maintenance entities, OAM messaging and functions occur
independently from the control plane. That is, in MPLS-TP OAM
mechanisms are responsible for monitoring and initiating recovery
actions (driving switches between primary and backup paths).
4.2.1. Management Plane Support
There is no MPLS-TP requirement for a standardized management
interface to the MPLS-TP control plane. That said, MPLS and GMPLS
support a number of standardized management functions. These include
the MPLS-TE/GMPLS TE Database Management Information Base (MIB), [TE-
MIB]; the MPLS TE MIB, [RFC3812]; the MPLS LSR MIB, [RFC3813]; the
GMPLS TE MIB [RFC4802]; and the GMPLS LSR MIB, [RFC4803]. These MIBs
may be used in MPLS-TP networks.
4.2.1.1. Recovery Triggers
The GMPLS control plane allows for management plane recovery triggers
and directly supports control plane recovery triggers. Support for
control plane recovery triggers is defined in [RFC4872] which refers
to the triggers as "Recovery Commands". These commands can be used
with both end-to-end and segment recovery, but are always controlled
on an end-to-end basis. The recovery triggers/commands defined in
[RFC4872] are:
a. Lockout of recovery LSP
b. Lockout of normal traffic
c. Forced switch for normal traffic
d. Requested switch for normal traffic
e. Requested switch for recovery LSP
Note that control plane triggers are typically invoked in response to
a management plane request at the ingress.
4.2.1.2. Management Plane / Control Plane Ownership Transfer
In networks where both control plane and management plane are
provided, LSP provisioning can be bone either by control plane or
management plane. As mentioned in the requirements section above, it
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must be possible to transfer, or handover, management plane created
LSP to the control plane domain and vice versa. [RFC5493] defines the
specific requirements for an LSP ownership handover procedure. It
must be possible for the control plane to notify, in a reliable
manner, the management plane about the status/result of either
synchronous or asynchronous, with respect to the management plane,
operation performed. Moreover it must be possible to monitor, via
query or spontaneous notify, the status of the control plane object
such as the TE Link status, the available resources, etc. A mechanism
must be made available by the control plane to the management plane
to log control plane LSP related operation, that is, it must be
possible from the NMS to have a clear view of the life, (traffic hit,
action performed, signaling etc.) of a given LSP. The LSP handover
procedure for MPLS-TP LSPs is supported via [RFC5852].
4.3. GMPLS and MPLS-TP Requirements Table
The following table shows how the MPLS-TP control plane requirements
can be met using existing the GMPLS control plane (which builds on
top of the MPLS control plane). 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 section 2.
+=======+===========================================================+
| Req # | References |
+-------+-----------------------------------------------------------+
| 1 | Generic requirement met by using Standards Track RFCs |
| 2 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 3 | [RFC5145] + Formal Definition (See Section 4.4.1) |
| 4 | Generic requirement met by using Standards Track RFCs |
| 5 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 6 | [RFC3471], [RFC3473], [RFC4875] |
| 7 | [RFC3471], [RFC3473] + |
| | Associated bidirectional LSPs (See Section 4.4.2) |
| 8 | [RFC4875] |
| 9 | [RFC3473] |
| 10 | Associated bidirectional LSPs (See Section 4.4.2) |
| 11 | Associated bidirectional LSPs (See Section 4.4.2) |
| 12 | [RFC3473] |
| 13 | [RFC5467] (Currently Experimental, See Section 4.4.3) |
| 14 | [RFC3945], [RFC3473], [RFC4202], [RFC4203], [RFC5307] |
| 15 | [RFC3945], [RFC3473], [RFC4202], [RFC4203], [RFC5307] |
| 16 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 17 | [RFC3945], [RFC4202] + proper vendor implementation |
| 18 | [RFC3945], [RFC4202] + proper vendor implementation |
| 19 | [RFC3945], [RFC4202] |
| 20 | [RFC3473] |
| 21 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307], |
| | [RFC5151] |
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| 22 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307], |
| | [RFC5151] |
| 23 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 24 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 25 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307], |
| | [HIERARCHY-BIS] |
| 26 | [RFC3473], [RFC4875] |
| 27 | [RFC3473], [RFC4875] |
| 28 | [RFC3945], [RFC3471], [RFC4202] |
| 29 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 30 | [RFC3945], [RFC3471], [RFC4202] |
| 31 | [RFC3945], [RFC3471], [RFC4202] |
| 32 | [RFC4208], [RFC4974], [RFC5787], [GMPLS-MLN] |
| 33 | [RFC3473], [RFC4875] |
| 34 | [RFC4875] |
| 35 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 36 | [RFC3473], [RFC3209] (Make-before-break) |
| 37 | [RFC3473], [RFC3209] (Make-before-break) |
| 38 | [RFC3945], [RFC4202], [RFC5718] |
| 39 | [RFC4139], [RFC4258], [RFC5787] |
| 40 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 41 | [RFC3473], [RFC5063] |
| 42 | [RFC3945], [RFC3471], [RFC4202], [RFC4208] |
| 43 | [RFC3945], [RFC3471], [RFC4202] |
| 44 | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 45 | [HIERARCHY-BIS], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 46 | [RFC3473], [RFC4203], [RFC5307], [RFC5063] |
| 47 | [RFC5493] |
| 48 | [RFC4872], [RFC4873] |
| 49 | [RFC3945], [RFC3471], [RFC4202] |
| 50 | [RFC4872], [RFC4873] + Recovery for P2MP (see Sec. 4.4.4) |
| 51 | [RFC4872], [RFC4873] |
| 52 | [RFC4872], [RFC4873] + proper vendor implementation |
| 53 | [RFC4872], [RFC4873], [GMPLS-PS] |
| 54 | [RFC4872], [RFC4873] |
| 55 | [RFC3473], [RFC4872], [RFC4873], [GMPLS-PS] |
| | Timers are a local implementation matter |
| 56 | [RFC4872], [RFC4873, [GMPLS-PS] + |
| | implementation of timers |
| 57 | [RFC4872], [RFC4873], [GMPLS-PS] |
| 58 | [RFC4872], [RFC4873] |
| 59 | [RFC4872], [RFC4873] |
| 60 | [RFC4872], [RFC4873] |
| 61 | [RFC4872], [RFC4873], [HIERARCHY-BIS] |
| 62 | [RFC4872], [RFC4873] |
| 63 | [RFC4872], [RFC4873] + Recovery for P2MP (see Sec. 4.4.4) |
| 64 | [RFC4872], [RFC4873] |
| 65 | [RFC4872], [RFC4873] |
| 66 | [RFC4872], [RFC4873] |
| 67 | [RFC4872], [RFC4873], [HIERARCHY-BIS] |
| 68 | [RFC4872], [RFC4873] |
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| 69 | [RFC3473], [RFC4872], [RFC4873] |
| 70 | [RFC3473] |
| 71 | [RFC3473], [RFC4872], [GMPLS-PS] |
| 72 | [RFC3473], [RFC4872] |
| 73 | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 74 | [RFC4426], [RFC4872], [RFC4873] |
| 75 | [RFC4426], [RFC4872], [RFC4873] |
| 76 | [RFC4426], [RFC4872], [RFC4873] |
| 77 | [RFC4426], [RFC4872], [RFC4873] |
| 78 | [RFC4426], [RFC4872], [RFC4873] |
| 79 | [RFC4426], [RFC4872], [RFC4873] + vendor implementation |
| 80 | [RFC4426], [RFC4872], [RFC4873] |
| 81 | [RFC4426], [RFC4872], [RFC4873] |
| 82 | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5) |
| 83 | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5) |
| 84 | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5) |
| 85 | [RFC4872], [RFC4873] + Testing control (See Sec. 4.4.5) |
| 86 | [RFC4872], [RFC4873], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 87 | [RFC4872], [RFC4873] |
| 88 | [RFC4872], [RFC4873] |
| 89 | [RFC4872], [RFC4873], [TP-RING] |
| 90 | [RFC4872], [RFC4873], [TP-RING] |
| 91 | [RFC3270], [RFC3473], [RFC4124] + GMPLS Usage (See 4.4.6) |
| 92 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] |
| 93 | [RFC3945], [RFC3473], [RFC2210], [RFC2211], [RFC2212] |
| 94 | Generic requirement on data plane (correct implementation)|
| 95 | [RFC3473], [NO-PHP] |
| 96 | [RFC3270], [RFC3473], [RFC4124] + GMPLS Usage (See 4.4.6) |
| 97 | PW only requirement, see PW Requirements Table (5.2) |
| 98 | PW only requirement, see PW Requirements Table (5.2) |
| 99 | [RFC3945], [RFC3473], [HIERARCHY-BIS] |
| 100 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] + |
| | [RFC5392] and [RFC5316] |
| 101 | PW only requirement, see PW Requirements Table (5.2) |
| 102 | (Requirement intentionally blank.) |
| 103 | [RFC3473], [RFC4203], [RFC5307], [RFC5063] |
| 104 | [RFC4872], [RFC4873], [TP-RING] |
| 105 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 106 | [RFC3473], [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 107 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 108 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5) |
| 109 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 110 | [RFC3473], [RFC4872], [RFC4873] |
| 111 | [RFC3473], [RFC4872], [RFC4873] |
| 112 | [RFC3473], [RFC4783] |
| 113 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 114 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5) |
| 115 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5) |
| 116 | [RFC3473] |
| 117 | [RFC4426], [RFC4872], [RFC4873] |
| 118 | [RFC3473], [RFC4872], [RFC4873] |
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| 119 | [RFC3473], [RFC4783] |
| 120 | [RFC3473] |
| 121 | [RFC3473], [RFC4783] |
| 122 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5) |
| 123 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] + (See Sec. 4.4.5) |
| 124 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT], [HIERARCHY-BIS] |
| 125 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
| 126 | [CCAMP-OAM-FWK], [CCAMP-OAM-EXT] |
+=======+===========================================================+
4.4. Anticipated MPLS-TP Related Extensions and Definitions
This section identifies the extensions and other documents that have
been identified as likely to be needed to support the full set of
MPLS-TP control plane requirements.
4.4.1. MPLS to MPLS-TP Interworking
[RFC5145] identifies a set of solutions that are aimed to aid in the
interworking of MPLS-TE and GMPLS control planes. This work will
serve as the foundation for a formal definition of MPLS to MPLS-TP
control plane interworking.
4.4.2. Associated Bidirectional LSPs
GMPLS signaling, [RFC3473], supports unidirectional, and co-routed
bidirectional point-to-point LSPs. MPLS-TP also requires support for
associated bidirectional point-to-point LSPs. Such support will
require an extension or a formal definition of how the LSP endpoints
supporting an associated bidirectional service will coordinate the
two LSPs used to provide such a service. Per requirement 11, transit
nodes that support an associated bidirectional service should be
aware of the association of the LSPs used to support the service.
There are several existing protocol mechanisms on which to base such
support, including, but not limited to:
o GMPLS calls, [RFC4974].
o The ASSOCIATION object, [RFC4872].
o The LSP_TUNNEL_INTERFACE_ID object, [HIERARCHY-BIS].
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4.4.3. Asymmetric Bandwidth LSPs
[RFC5467] defines support for bidirectional LSPs which have different
(asymmetric) bandwidth requirements for each direction. This RFC can
be used to meet the related MPLS-TP technical requirement, but this
RFC is currently an Experimental RFC. To fully satisfy MPLS-TP
requirement this document will need to become a Standards Track RFC.
4.4.4. Recovery for P2MP LSPs
The definitions of P2MP, [RFC4875], and GMPLS recovery, [RFC4872] and
[RFC4873], do not explicitly cover their interactions. MPLS-TP
requires a formal definition of recovery techniques for P2MP LSPs.
Such a formal definition will be based on existing RFCs and may not
require any new protocol mechanisms, but nonetheless, must be
documented.
4.4.5. Test Traffic Control and other OAM functions
[CCAMP-OAM-FWK] and [CCAMP-OAM-EXT] are works in progress that extend
the OAM related control capabilities of GMPLS. These extensions
cover a portion, but not all OAM related control functions that have
been identified in the context of MPLS-TP. As discussed above, the
MPLS-TP control plane must support the selection of which (if any)
OAM function(s) to use (including support to select experimental OAM
functions) and what OAM functionality to run, including, continuity
check (CC), connectivity verification (CV), packet loss and delay
quantification, and diagnostic testing of a service. As OAM
configuration is directly linked to data plane OAM, it is expected
that [CCAMP-OAM-EXT] will evolve in parallel with the specification
of data plane OAM functions.
4.4.6. DiffServ Object usage in GMPLS
[RFC3270] and [RFC4124] defines support for DiffServ enabled MPLS
LSPs. While the document references GMPLS signaling, there is no
explicit discussion on the use of the DiffServ related objects in
GMPLS signaling. A (possibly Information) document on how GMPLS
supports DiffServ LSPs is likely to prove useful in the context of
MPLS-TP.
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5. Pseudowires
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)
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 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 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-PW) [RFC3985], and (2) Multi-segment Pseudowires (MS-PW)
[RFC5659]. An MPLS-TP domain may transparently transport a PW whose
endpoints 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 which is then transported in an LSP
over an MPLS-TP domain. 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. The MPLS-TP domain may also contain Switching PEs
(S-PEs) for a multi-segment PW whereby the T-PEs may be at the edge
of the MPLS-TP domain or in a client network. In this latter case, a
T-PE in a client network is a T-PE performing the adaptation of the
native service to MPLS and the MPLS-TP domain performs Pseudo-wire
switching.
SS-PW signaling control plane is based on LDP with specific
procedures defined in [RFC4447]. [RFC5659], [SEGMENTED-PW] and [MS-
PW-DYNAMIC] allow for static switching of multi-segment Pseudowires
in data and control plane and for dynamic routing and placement of an
MS-PW whereby signaling is still based on Targeted LDP (T-LDP). The
MPLS-TP domain 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 segment that is
switched across the MPLS-TP domain.
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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 section 2.
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 pseudo-
wires. 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.
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+=======+===========================================================+
| Req # | References |
+-------+-----------------------------------------------------------+
| 1 | Generic requirement met by using Standards Track RFCs |
| 2 | [RFC3985], [RFC4447], Together with TP-LSPs (Sec. 4.3) |
| 3 | [RFC3985], [RFC4447] |
| 4 | Generic requirement met by using Standards Track RFCs |
| 5 | [RFC3985], [RFC4447], Together with TP-LSPs |
| 6 | [RFC3985], [RFC4447], [PW-P2MPR], [PW-P2MPE] + TP-LSPs |
| 7 | [RFC3985], [RFC4447], + TP-LSPs |
| 8 | [PW-P2MPR], [PW-P2MPE] |
| 9 | [RFC3985], end-node only involvement for PW |
| 10 | [RFC3985], proper vendor implementation |
| 11 | [RFC3985], end-node only involvement for PW |
| 12-13 | [RFC3985], [RFC4447], See Section 5.3.4 |
| 14 | [RFC3985], [RFC4447] |
| 15 | [RFC4447], [RFC3478], proper vendor implementation |
| 16 | [RFC3985], [RFC4447] |
| 17-18 | [RFC3985], proper vendor implementation |
| 19-26 | [RFC3985], [RFC4447], [RFC5659], implementation |
| 27 | [RFC4448], [RFC4816], [RFC4618], [RFC4619], [RFC4553] |
| | [RFC4842], [RFC5287] |
| 28 | [RFC3985] |
| 29-31 | [RFC3985], [RFC4447] |
| 32 | [RFC3985], [RFC4447], [RFC5659], See Section 5.3.6. |
| 33 | [RFC4385], [RFC4447], [RFC5586] |
| 34 | [PW-P2MPR], [PW-P2MPE] |
| 35 | [RFC4863] |
| 36-37 | [RFC3985], [RFC4447], See Section 5.3.4 |
| 38 | [RFC5586] |
| 39 | Provided by TP-LSPs |
| 40 | [RFC3985], [RFC4447], + TP-LSPs |
| 41 | [RFC3478] |
| 42-43 | [RFC3985], [RFC4447] |
| 44-45 | [RFC3985], [RFC4447], + TP-LSPs - See Section 5.3.5 |
| 46 | [RFC3985], [RFC4447], [RFC5659] + TP-LSPs |
| 47 | [RFC3985], [RFC4447], + TP-LSPs - See Section 5.3.3 |
| 48 | [PW-RED], [PW-REDB] |
| 49-50 | [RFC3985], [RFC4447], + TP-LSPs, implementation |
| 51-53 | Provided by TP-LSPs, and Section 5.3.5 |
| 54-56 | [RFC3985], [RFC4447], See Section 5.3.5 |
| 57 | [PW-RED], [PW-REDB] |
| | revertive/non-revertive behavior is a local matter for PW |
| 58-59 | [PW-RED], [PW-REDB] |
| 60-82 | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5 |
| 83-84 | [RFC5085], [RFC5586], [RFC5885] |
| 85-90 | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5 |
| 91-96 | [RFC3985], [RFC4447], + TP-LSPs, implementation |
| 97 | [RFC4447], [MS-PW-DYNAMIC] |
| 98 | [RFC4447] |
| 99 - | |
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| 100 | Not Applicable to PW |
| 101 | [RFC4447] |
| 102 | (Requirement intentionally blank.) |
| 103 | [RFC3478] |
| 104 | [RFC3985], + TP-LSPs |
| 105 | [PW-OAM] |
| 106 | [PW-OAM] |
| 107 - | |
| 109 | [RFC5085], [RFC5586], [RFC5885] |
| 110 | [RFC5085], [RFC5586], [RFC5885] |
| | fault reporting and protection triggering is a local |
| | matter for PW |
| 111 | [RFC5085], [RFC5586], [RFC5885] |
| | fault reporting and protection triggering is a local |
| | matter for PW |
| 112 | [RFC4447] |
| 113 | [RFC4447], [RFC5085], [RFC5586], [RFC5885] |
| 114 | [RFC5085], [RFC5586], [RFC5885] |
| 115 | [RFC5085], [RFC5586], [RFC5885] |
| 116 | path traversed by PW is determined by LSP path, see |
| | GMPLS and MPLS-TP Requirements Table, 4.3 |
| 117 | [PW-RED], [PW-REDB], administrative control of redundant |
| | PW is a local matter at the PW head-end |
| 118 | [PW-RED], [PW-REDB], [RFC5085], [RFC5586], [RFC5885] |
| 119 | [RFC3985], [RFC4447], [PW-RED], [PW-REDB], Section 5.3.5 |
| 120 | [RFC4447] |
| 121 - | |
| 126 | [RFC5085], [RFC5586], [RFC5885] |
+=======+===========================================================+
5.3. Anticipated MPLS-TP Related Extensions
The same control protocol and procedures will be reused as much as
possible. However, when using PWs in MPLS-TP, a set of new
requirements are defined which may require extensions of the existing
control mechanisms. This section clarifies the areas where extensions
are needed based on the PW Control Plane related requirements
documented in [RFC5654].
See the table in the section above for a list of how requirements
defined in [RFC5654] are expected to be addressed.
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], [SEGMENTED-PW] and [MS-PW-DYNAMIC].
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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 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 networks
elements 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 signal initiation
end to inform the targeted LSR (at the signal termination end) which
LSP the resulting PW is to be bound to, 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.
If the control plane is physically separated from the forwarder, the
control plane must be able to program the forwarders with necessary
information.
For transport services, it may be required that bidirectional traffic
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, 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
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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 same S-PEs in both directions.
MPLS-TP imposes new requirements on the PW Control Plane, in
requiring that PW or PW segment 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.
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-guaranteed LSP.
In conjunction with explicit PW-to-LSP binding, existing mechanisms
may be sufficient, however this needs to be verified in detailed
evaluation.
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5.3.5. Support for PW Protection and PW OAM Configuration
The PW control plane must be able to establish and configure all of
the available features manageable for the PW, including protection
and OAM entities and mechanisms. There is ongoing work on PW
protection and MPLS-TP OAM.
5.3.6. Client Layer Interfaces to Pseudowire Control
Additional work is likely to be required to define consistent access
by a client layer network to control information available to the
client layer 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.
5.4. Pseudowire OAM and Recovery (Redundancy)
Many of the requirements listed in section 2 are intended to support
connectivity and performance monitoring (grouped together as OAM) and
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 drafts [PW-RED] and [PW-
REDB] that define - respectively - how to establish redundant
Pseudowires and how to indicate which is in use. Additional work may
be required.
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 but one of the functions that a
transport service requires OAM for. 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
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period of time - when explicitly enabled (for diagnostics, for
example).
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
functions.
6. Security Considerations
This document primarily describes how exiting 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 [MPLS-SEC].
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.
7. IANA Considerations
There are no new IANA considerations introduced by this document.
8. Acknowledgments
The authors would like to acknowledge the contributions of Yannick
Brehon, Diego Caviglia, Nic Neate, and Dave Mcdysan to this work.
9. References
9.1. Normative References
[RFC2210] Wroclawski, J., "The Use of RSVP with Integrated
Services", RFC 2210, September 1997.
[RFC2211] Wroclawski, J., "Specification of the Controlled Load
Quality of Service", RFC 2211, September 1997.
[RFC2212] Shenker, S., Partridge, C., and R Guerin, "Specification
of Guaranteed Quality of Service", RFC 2212, September
1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels," RFC 2119.
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[RFC3031] Rosen, E., Viswanathan, A., Callon, R.,
"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., "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, January 2003.
[RFC3478] Leelanivas, M, et al, "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 2003.
[RFC4124] Le Faucheur, F., Ed. "Protocol Extensions for Support of
Diffserv-aware MPLS Traffic Engineering", RFC 4124, June
2005.
[RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in
Support of Generalized Multi-Protocol Label
Switching(GMPLS)", RFC 4202, October 2005.
[RFC4203] Kompella, K. and Y. Rekhter, "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., et al, "Pseudowire Emulation Edge-to-Edge
(PWE3) Control Word for Use over an MPLS PSN", RFC
4385, February 2006.
[RFC4447] Martini, L., Ed., "Pseudowire Setup and Maintenance
Using the Label Distribution Protocol (LDP)", RFC
4447, April 2006.
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[RFC4448] Martini, L., Ed., "Encapsulation Methods for
Transport Ethernet over MPLS Network", RFC 4448,
April 2006.
[RFC4842] Malis, A., et al, "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., Rekhter, Y., and Papadimitriou, D.,
"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., Farrel, A.,
"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC4929] Andersson, L. and A. Farrel, "Change Process for
Multiprotocol Label Switching (MPLS) and Generalized
MPLS (GMPLS) Protocols and Procedures", BCP 129, RFC
4929, June 2007.
[RFC4974] Papadimitriou, D., Farrel, A., "Generalized MPLS (GMPLS)
RSVP-TE Signaling Extensions in Support of Calls", RFC
4974, August 2007.
[RFC5063] Satyanarayana, A., Ed., "Extensions to GMPLS Resource
Reservation Protocol (RSVP) Graceful Restart", RFC 5063,
September 2007.
[RFC5287] Vainshtein, A. and Y. Stein, "Control Protocol Extensions
for the Setup of Time-Division Multiplexing (TDM)
Pseudowires in MPLS Networks", RFC 5287, August 2008.
[RFC5305] Smit, H. and T. Li, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC5307] Kompella, K. and Rekhter, Y., "IS-IS Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, October 2008.
[RFC5316] Chen, M., Zhang, R., and Duan, X., "ISIS Extensions
in Support of Inter-Autonomous System (AS) MPLS and
GMPLS Traffic Engineering", RFC 5316, December 2008.
[RFC5392] Chen, M., Zhang, R., and Duan, X., "OSPF Extensions
in Support of Inter-Autonomous System (AS) MPLS and
GMPLS Traffic Engineering", RFC 5392, January 2009.
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[RFC5151] Farrel, A., Ed., "Inter-Domain MPLS and GMPLS Traffic
Engineering -- Resource Reservation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 5151, February 2008.
[RFC5654] Niven-Jenkins, B., et al, "Requirements of an MPLS
Transport Profile", RFC 5654, September 2009.
[RFC5467] Berger, L., et al, "GMPLS Asymmetric Bandwidth
Bidirectional Label Switched Paths (LSPs)", RFC 5467, March
2009.
[RFC5586] Bocci, M., et al, "MPLS Generic Associated Channel", RFC
5586, June 2009.
[RFC5860] Vigoureux, M., Ward, D., Betts, M.,
"Requirements for Operations, Administration, and
Maintenance
(OAM) in MPLS Transport Networks", RFC 5860, May 2010.
[TP-DATA] Frost, D., Bryant, S., Bocci, M.,
"MPLS Transport Profile Data Plane Architecture", work in
progress, draft-ietf-mpls-tp-data-plane.
[TP-FWK] Bocci, M., Ed., et al, "A Framework for MPLS in
Transport Networks", work in progress,
draft-ietf-mpls-tp-framework.
[TP-OAM] Busi, I., Ed., Niven-Jenkins, B., Ed., "MPLS-TP OAM
Framework and Overview", work in progress,
draft-ietf-mpls-tp-oam-framework.
[TP-SURVIVE] Sprecher, N., et al., "Multiprotocol Label
Switching Transport Profile Survivability
Framework", work in progress,
draft-ietf-mpls-tp-survive-fwk.
9.2. Informative References
[CCAMP-OAM-FWK] A. Takacs, D. Fedyk, and J. He, "OAM Configuration
Framework and Requirements for GMPLS RSVP-TE", work
in progress, draft-ietf-ccamp-oam-configuration-fwk.
[CCAMP-OAM-EXT] Bellagamba, E., et.al., "RSVP-TE Extensions for
MPLS-TP OAM Configuration", work in progress,
draft-bellagamba-ccamp-rsvp-te-mpls-tp-oam-ext.
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[GMPLS-MLN] Papadimitriou, D., et al, "Generalized Multi-Protocol
Label Switching (GMPLS) Protocol Extensions for
Multi-Layer and Multi-Region Networks (MLN/MRN)", work
in progress, draft-ietf-ccamp-gmpls-mln-extensions.
[GMPLS-PS] Takacs, A., et al, "GMPLS RSVP-TE Recovery Extension
for data plane initiated reversion and protection timer
signalling", work in progress,
draft-takacs-ccamp-revertive-ps.
[HIERARCHY-BIS] Shiomoto, K, Ed., Farrel, A, Ed., "Procedures for
Dynamically Signaled Hierarchical Label Switched
Paths", work in progress,
draft-ietf-ccamp-lsp-hierarchy-bis.
[TE-MIB] T Otani, et.al., "Traffic Engineering Database Management
Information Base in support of MPLS-TE/GMPLS", work in
progress, draft-ietf-ccamp-gmpls-ted-mib.
[MS-PW-DYNAMIC] L. Martini, M Bocci, and F Balus "Dynamic
Placement of Multi Segment Pseudo Wires",
work in progress, draft-ietf-pwe3-dynamic-ms-pw.
[ITU.G8080.2006] International Telecommunications Union,
"Architecture for the automatically switched
optical network (ASON)", ITU- T Recommendation
G.8080, June 2006.
[ITU.G8080.2008] International Telecommunications Union,
"Architecture for the automatically switched
optical network (ASON) Amendment 1", ITU-T
Recommendation G.8080 Amendment 1, March 2008.
[MPLS-SEC] Fang, L., et al, "Security Framework for MPLS and
GMPLS Networks", work in progress,
draft-ietf-mpls-mpls-and-gmpls-security-framework.
[NO-PHP] Ali, z., et al, "Non PHP Behavior and out-of-band mapping
for RSVP-TE LSPs", work in progress,
draft-ietf-mpls-rsvp-te-no-php-oob-mapping
[SEGMENTED-PW] Martini, L., Nadeau, T., and Duckett M.,
"Segmented Pseaudowire", work in progress,
draft-ietf-pwe3-segmented-pw.
[TP-P2MP-FWK] D. Frost, M. Bocci, and L. Berger, "A Framework for
Point-to-Multipoint MPLS in Transport Networks",
draft-fbb-mpls-tp-p2mp-framework.
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[RFC3270] Le Faucheur, F., et al, "Multi-Protocol Label
Switching (MPLS) Support of Differentiated
Services", RFC 3270, May 2002.
[RFC3472] Ashwood-Smith, P., Ed, Berger, L. Ed., "Generalized
Multi-Protocol Label Switching (GMPLS) Signaling
Constraint-based Routed Label Distribution Protocol
(CR-LDP) Extensions", RFC 3472, January 2003.
[RFC3477] Kompella, K., Rekhter, Y., "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003.
[RFC3478] Leelanivas, M., Rekhter, Y., Aggarwal, R., "Graceful
Restart Mechanism for Label Distribution Protocol", RFC
3478, February 2003.
[RFC3812] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Traffic
Engineering (TE) Management Information Base (MIB)", RFC
3812, June 2004.
[RFC3813] Srinivasan, C., Viswanathan, A., and T. Nadeau,
"Multiprotocol Label Switching (MPLS) Label Switching
(LSR) Router Management Information Base (MIB)", RFC
3813, June 2004.
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October
2004.
[RFC3985] Bryant, S. and P. Pate, "Pseudowire Emulation Edge-
to-Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC4139] Papadimitriou, D., et al, "Requirements for
Generalized MPLS (GMPLS) Signaling Usage and
Extensions for Automatically Switched Optical
Network (ASON)", RFC4139, July 2005.
[RFC4201] Kompella, K., Rekhter, Y., Berger, L.,
"Link Bundling in MPLS Traffic Engineering (TE)", RFC 4201,
October 2005.
[RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Rekhter,
Y., "Generalized Multi-Protocol Label Switching
(GMPLS) User-Network Interface (UNI) : Resource
ReserVation Protocol-Traffic Engineering (RSVP-TE)
Support for the Overlay Model", RFC 4208, October
2005.
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[RFC4258] Brungard, D., et al, "Requirements for Generalized
Multi-Protocol Label Switching (GMPLS) Routing for
the Automatically Switched Optical Network (ASON)",
RFC4258, November 2005.
[RFC4379] Kompella, K. and G. Swallow, "Detecting
Multi-Protocol Label Switched (MPLS) Data Plane
Failures", RFC 4379, February 2006.
[RFC4426] Lang, J., Rajagopalan B., and D.Papadimitriou, Editors,
"Generalized Multiprotocol Label Switching (GMPLS)
Recovery Functional Specification", RFC 4426, March 2006.
[RFC4427] Mannie, E., Papadimitriou, D., "Recovery (Protection
and Restoration) Terminology for Generalized
Multi-Protocol Label Switching (GMPLS)", RFC4427,
March 2006.
[RFC4553] Vainshtein, A., Ed., and Stein, YJ., Ed.,"Structure-
Agnostic Time Division Multiplexing (TDM) over Packet
(SAToP)", RFC 4553, June 2006.
[RFC4618] Martini, L., Rosen, E., Heron, G., and Malis, A.,
"Encapsulation Methods for Transport of PPP/High-
Level Data Link Control (HDLC) over MPLS Networks",
RFC 4618, September 2006.
[RFC4619] Martini, L., Ed., Kawa, C., Ed., and Malis, A., Ed.,
"Encapsulation Methods for Transport of Frame Relay
over Multiprotocol Label Switching (MPLS) Networks",
September 2006.
[RFC4655] Farrel, A., Vasseur, J.-P., Ash, J.,
"A Path Computation Element (PCE)-Based Architecture", RFC
4655, August 2006.
[RFC4783] Berger, L.,Ed., "GMPLS - Communication of Alarm
Information", RFC 4763, December 2006.
[RFC4802] T. D. Nadeu and A. Farrel, "Generalized Multiprotocol
Label Switching (GMPLS) Traffic Engineering Management
Information Base", RFC 4802, February 2007.
[RFC4803] T. D. Nadeu and A. Farrel, "Generalized Multiprotocol
Label Switching (GMPLS) Label Switching Router (LSR)
Management Information Base", RFC 4803, February 2007.
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[RFC4816] Malis, A., Martini, L., Brayley, J., and Walsh, T.,
"Pseudowire Emulation Edge-to-Edge (PWE3)
Asynchronous Transfer Mode (ATM) Transparent Cell
Transport Service", RFC 4816, February 2007.
[RFC4875] Aggarwal, R., Papadimitriou, D., Yasukawa, S.,
"Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual
Circuit Connectivity Verification (VCCV) : A Control
Channel for Pseudowires", RFC 5085, December 2007.
[RFC5145] Shiomoto, K.,
"Framework for MPLS-TE to GMPLS Migration", RFC 5145, March
2008.
[RFC5440] Vasseur, JP., Le, JL.,
"Path Computation Element (PCE) Communication Protocol
(PCEP)", RFC 5440, March 2009.
[RFC5493] Caviglia, D., et al, "Requirements for the
Conversion between Permanent Connections and
Switched Connections in a Generalized Multiprotocol
Label Switching (GMPLS) Network", RFC 5493, April
2009.
[RFC5659] Bocci, M., and Bryant, B., "An Architecture for
Multi-Segment Pseudowire Emulation Edge-to-Edge",
RFC 5659, October 2009.
[RFC5718] Bellar, D., Farrel, A., "An In-Band Data Communication
Network For the MPLS Transport Profile", RFC 5718, January
2010.
[RFC5787] Papadimitriou, D., "OSPFv2 Routing Protocols
Extensions for ASON Routing", RFC 5787, March 2010.
[RFC5852] Caviglia, D., Ceccarelli, D., Bramanti, D., Li, D.,
Bardalai, S., "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.
Andersson, et al Informational [Page 47]
Internet-Draft draft-ietf-ccamp-mpls-tp-cp-framework-02.txt June 18, 2010
[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional
Forwarding Detection (BFD) for the Pseudowire
Virtual Circuit Connectivity Verification (VCCV)",
RFC 5885, June 2010.
[PW-RED] Muley, P., et al, "Pseudowire (PW) Redundancy", work in
progress, draft-ietf-pwe3-redundancy.
[PW-REDB] Muley, P., et al, "Preferential Forwarding Status bit
definition", work in progress,
draft-ietf-pwe3-redundancy-bit.
[PW-OAM] Zhang, F., et al, "LDP Extensions for MPLS-TP PW OAM
configuration", work in progress,
draft-zhang-mpls-tp-pw-oam-config.
[PW-P2MPE] Aggarwal, R. and F. Jounay, "Point-to-Multipoint
Pseudo-Wire Encapsulation", work in progress,
draft-raggarwa-pwe3-p2mp-pw-encaps.
[PW-P2MPR] Jounay, F., et al, "Requirements for
Point-to-Multipoint Pseudowire", work in progress,
draft-ietf-pwe3-p2mp-pw-requirements.
[TP-RING] Weingarten, Y., Ed., "MPLS-TP Ring Protection", work in
progress, draft-weingarten-mpls-tp-ring-protection.
10. Authors' Addresses
Loa Andersson (editor)
Ericsson
Phone: +46 10 717 52 13
Email: loa.andersson@ericsson.com
Lou Berger (editor)
LabN Consulting, L.L.C.
Phone: +1-301-468-9228
Email: lberger@labn.net
Luyuan Fang (editor)
Cisco Systems, Inc.
300 Beaver Brook Road
Boxborough, MA 01719
USA
Email: lufang@cisco.com
Andersson, et al Informational [Page 48]
Internet-Draft draft-ietf-ccamp-mpls-tp-cp-framework-02.txt June 18, 2010
Nabil Bitar (editor)
Verizon,
40 Sylvan Rd.,
Waltham, MA 02451
Email: nabil.n.bitar@verizon.com
Attila Takacs
Ericsson
1. Laborc u.
Budapest, HUNGARY 1037
Email: attila.takacs@ericsson.com
Martin Vigoureux
Alcatel-Lucent
Email: martin.vigoureux@alcatel-lucent.fr
Elisa Bellagamba
Ericsson
Farogatan, 6
164 40, Kista, Stockholm, SWEDEN
Email: elisa.bellagamba@ericsson.com
Eric Gray
Ericsson
900 Chelmsford Street
Lowell, MA, 01851
Phone: +1 978 275 7470
Email: Eric.Gray@Ericsson.com
Andersson, et al Informational [Page 49]
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