Internet Draft Loa Andersson, Ed. (Acreo AB) Category: Informational Lou Berger, Ed. (LabN) Expiration Date: August 22, 2010 Luyuan Fang, Ed. (Cisco) Nabil Bitar, Ed. (Verizon) February 22, 2010 MPLS-TP Control Plane Framework draft-abfb-mpls-tp-control-plane-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. The control plane for Pseudowires (PWs) is also covered by this document. Management plane functions such as manual configuration and the initiation of LSP setup are out of scope of this document. 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Table of Contents 1 Introduction ........................................... 3 1.1 Conventions Used In This Document ...................... 3 1.2 Scope .................................................. 3 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 .............................. 31 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 ............................................ 32 Andersson, et al Informational [Page 2] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 5.1 General reuse of existing PW control plane mechanisms .. 35 5.2 Signaling .............................................. 35 5.3 Recovery (Redundancy) .................................. 35 6 Network Managment Considerations ....................... 35 7 Security Considerations ................................ 35 8 IANA Considerations .................................... 36 9 Acknowledgments ........................................ 36 10 References ............................................. 36 10.1 Normative References ................................... 36 10.2 Informative References ................................. 38 11 Authors' Addresses ..................................... 43 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 functionalities 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]. 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 Andersson, et al Informational [Page 3] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 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 signaling that is used to provision PWs as specified in [RFC4447]. This document also discusses the impact of the MPLS-TP requirements on the GMPLS signaling and routing protocols that is used to provision MPLS-TP LSPs. 1.3. Basic Approach The basic approach taken in defining the MPLS-TP Control Plane framework is: 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 Andersson, et al Informational [Page 4] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 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 LDP for PW signaling. In both cases, OSPF-TE or ISIS-TE with GMPLS extensions is used for dynamic routing. 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. It shows the control plane protocols used by MPLS-TP, as well as the UNI and NNI reference points. Andersson, et al Informational [Page 5] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 |< ---- 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 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], and 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 end-points. Note that segement MEPs end- points are collocated with MIPs of the next higher-layer (e.g., end- to-end) LSPs. Andersson, et al Informational [Page 6] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 |< ------- 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. Andersson, et al Informational [Page 7] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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], [TP-OAM-REQ], [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 that interworking 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]. Andersson, et al Informational [Page 8] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 10. Edge nodes (i.e., ingress and egress) must be aware about 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 about 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]. Andersson, et al Informational [Page 9] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 support 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]. Andersson, et al Informational [Page 10] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. 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]. Andersson, et al Informational [Page 11] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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]. Andersson, et al Informational [Page 12] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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]. Andersson, et al Informational [Page 13] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 may 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]. Andersson, et al Informational [Page 14] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 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]. Andersson, et al Informational [Page 15] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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). 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 and relative end-to-end bandwidth guarantees [RFC5654, requirement 111]. [Editor's note: add reference to definition of hard and relative guarantees] 93. The MPLS-TP control plane must support the provisioning of services which are sensitive to jitter and delay [RFC5654, requirement 112]. Andersson, et al Informational [Page 16] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 2.2. MPLS-TP Framework Derived Requirements The following additional requirements are based on [TP-FWK]: [Editor's note: Need to update section (on document) to match split of P2P and P2MP now in [TP-FWK] and [TP-P2MP-FWK].) 94. Per-packet equal cost multi-path (ECMP) load balancing is not applicable to MPLS-TP [TP-FWK, section 3.3.2, paragraph 9]. 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 general providing packet transport services will be clarified in a future version. [TP-FWK, section 3.3.2, paragraph 10] 96. The MPLS-TP control plane must support both E-LSP and L-LSP MPLS DiffServ modes as specified in [RFC3270] [TP-FWK, section 3.3.2, paragraph 11]. 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 3.4.2.]. 98. The MPLS-TP control plane must support the control of PWs and their associated labels [TP-FWK, section 3.4.2.]. 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 3.4.3.]. a. The MPLS-TP control plane must support the use of network layer protocol-specific LSPs and labels. [TP-FWK, section 3.4.3.] b. The MPLS-TP control plane must support the use of a client service-specific LSPs and labels. [TP-FWK, section 3.4.3.] 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 3.8.]. 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 3.8, paragraph 6]. Andersson, et al Informational [Page 17] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 102. The MPLS-TP LSP control plane must allow for interoperation with the MPLS-TE LSP control plane [TP-FWK, section 3.8.2., paragraph 5]. 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-06, section 3.8., paragraph 12]. 104. The MPLS-TP control plane must support linear, ring and meshed protection schemes [TP-FWK-06, section 3.10., paragraph 8]. 2.3. OAM Framework Derived Requirements The following additional requirements are based on [TP-OAM-REQ] and [TP-OAM]: 105. The MPLS-TP control plane must support the capability to enable/disable OAM functions as part of service establishment [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [BFD-MPLS], VCCV [RFC5085] and VCCV-BFD [VCCV-BFD]) [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, section 2.2.1., paragraph 1]. 111. The MPLS-TP control plane must allow 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 [TP-OAM-REQ, section 2.2.1., paragraph 2]. Andersson, et al Informational [Page 18] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 [TP-OAM- REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP- OAM-REQ, section 2.2.6., paragraph 1]. (This requirement duplicates a requirement stated above but is listed again to maintain alignment with [TP-OAM].) 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, 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 [TP-OAM-REQ, section 2.2.9., Andersson, et al Informational [Page 19] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 paragraph 1]. 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 [TP-OAM- REQ, 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 [TP-OAM-REQ, 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 [TP- OAM-REQ, section 2.2.12., paragraph 1]. 124. The MPLS-TP control plane must support the configuration of MEPs. [Editor's note: this set of requirements needs to be aligned with the current terminology in [TP-OAM].] 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 a sub-layer (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 [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]. 127. [NOTE: Need to review NM frawework for derived requirments] Andersson, et al Informational [Page 20] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. As this coordination occurs within a single node, this coordination is a local matter and is out of scope of this document. 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 LSP layer. PW based recovery is under development at this time and Andersson, et al Informational [Page 21] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. Andersson, et al Informational [Page 22] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. Andersson, et al Informational [Page 23] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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, 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), 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. Andersson, et al Informational [Page 24] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. Andersson, et al Informational [Page 25] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. The former 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 each MEP (other than the ones co-resident with the ingress and egress) are instantiated via a hierarchical LSP and protection is always end-to-end. (Which 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 interprovider, external network-to-network (E-NNI), interfaces. Such support is embodied in [RFC4208] for UNIs and [GMPLS-ASON] 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 [TP-OAM-REQ]. 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]. Andersson, et al Informational [Page 26] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 Many OAM functions occur on a per-LSP, and even in-band, basis 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 mis-configuration 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 Andersson, et al Informational [Page 27] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 [PC-SCP]. 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] | Andersson, et al Informational [Page 28] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 | 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], [GMPLS-ASON], [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], [GMPLS-ASON] | | 40 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] | | 41 | [RFC3473] | | 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 | [PC-SCP] | | 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] | Andersson, et al Informational [Page 29] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 | 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] | | 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 implmentation) | | 95 | [RFC3473], [NO-PHP] | | 96 | [RFC3270], [RFC3473], [RFC4124] + GMPLS Usage (See 4.4.6) | | 97 | [RFC3473] (See Section 3) | | 98 | [RFC3473] (See Section 3) | | 99 | [RFC3945], [RFC3473], [HIERARCHY-BIS] | | 100 | [RFC3945], [RFC4202], [RFC3473], [RFC4203], [RFC5307] + | | | [RFC5392] and [RFC5316] | | 101 | PW only requirement | | 102 | [RFC5145] + Formal Definition (See Section 4.4.1) | | 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] | | 119 | [RFC3473], [RFC4783] | Andersson, et al Informational [Page 30] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 | 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] | | 127 | TBD | +=======+===========================================================+ 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. GMPLS calls, [RFC4974], may serve as the foundation for this support. 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. Andersson, et al Informational [Page 31] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 of 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. 5. Pseudowires [Editor's note: This section is preliminary and will be edited/replaced in future versions.] 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 Andersson, et al Informational [Page 32] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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 types of PWs: (1) Single-Segment pseudowires (SS-PW), and (2) Multi-segment pseudowires (MS-PW) [SEGMENTED-PW]. 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 for transport over an MPLS-TP domain, with a GMPLS LSP or a hierarchy of LSPs transporting the PW between the T-PEs. 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. The same control protocol and procedures are 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 identifies areas where extensions are needed based on the PW Control Plane related requirements documented in [RFC5654]. 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]. For MPLS-TP, it is required that the data and control planes are both logically and physically separated. That is, the PW Control Plane must be able to operate out-of-band (OOB). This separation ensures Andersson, et al Informational [Page 33] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 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. 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 FFS). The PW Label allocation and exchange mechanisms can be possibly reused unchanged (Detailed evaluation is FFS). Binding a PW to an LSP, or PW segments to LSPs can be 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. 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 applications, it is mandatory that bidirectional traffic is following congruent paths. Today, 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. The only requirement today is that a PW or a PW segment shares the same T-PEs in both directions, and same S-PEs in both directions. This poses a new requirement on the PW Control Plane, namely to ensure that both ends map the PW to the same transport path. 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 likely can be accomplished by adding a new TLV to PW signaling. This coincides with the gap identified for OOB support: a new mechanism may be needed to explicitly bind PWs to the supporting transport LSP. Alternatively, two unidirectional LSPs may be used to support the PW. However, to meet the congruency requirement, the LSPs must be placed so that they are forced to follow the same path (switches and links). This maybe accomplished by placing one unidirectional TE-LSP in one direction at one endpoint, and forcing the other endpoint to setup a TE-LSP with an ERO that has the nodes/links in the reverse order from the RRO seen in the path message of the LSP in the reverse direction. In this case, when one endpoint selects an LSP to bind the PW to, it must identify to the remote end which LSP to bind the other direction of the PW to. Transport applications require resource guarantees. In the case of transport LSPs, resource reservation mechanisms are provided via RSVP-TE and the use of DiffServ. If multiple PWs are multiplexed into Andersson, et al Informational [Page 34] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 the same transport LSP resources, contention may occur. However, local policy at PEs may 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. 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. To summarize, the main areas identified for potential PW Control Plane extensions to support MPLS-TP are the following. o Move PW Control Plane out-of-band o Explicit control of PW to LSP binding o PW QoS o PW protection o PW OAM configuration and control 5.1. General reuse of existing PW control plane mechanisms 5.2. Signaling 5.3. Recovery (Redundancy) 6. Network Managment Considerations [Editor's note: TBD] 7. Security Considerations This primarily document 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. Andersson, et al Informational [Page 35] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 8. IANA Considerations There are no new IANA considerations introduced by this document. 9. Acknowledgments The authors would like to acknowledge the contributions of Yannick Brehon, Diego Caviglia, Nic Neate, and Dave Mcdysan to this work. 10. References 10.1. 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. [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", January 2003. [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. Andersson, et al Informational [Page 36] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [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. [RFC4447] Martini, L., Ed., "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC4448] Martini, L., Ed., "Encapsulation Methods for Transport Ethernet over MPLS Network", RFC 4448, April 2006. [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. [RFC5305] Smit, H. and T. Li, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008. Andersson, et al Informational [Page 37] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [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. [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. [TP-FWK] Bocci, M., Ed., Et al, "A Framework for MPLS in Transport Networks", work in Progress, draft-ietf-mpls-tp-framework-10, February 2010. [TP-OAM] Busi, I., Ed., Niven-Jenkins, B., Ed., "MPLS-TP OAM Framework and Overview", work in Progress, draft-ietf-mpls-tp-oam-framework-04 December 2009. [TP-OAM-REQ] Vigoureux, M., Ward, D, and Betts, M., "Requirements for OAM in MPLS Transport Networks", work in progress, draft-ietf-mpls-tp-oam-requirements. [TP-SURVIVE] Sprecher, N., et al., "Multiprotocol Label Switching Transport Profile Survivability Framework", work in Progress, draft-ietf-mpls-tp-survive-fwk. 10.2. Informative References [BFD-MPLS] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD For MPLS LSPs", draft-ietf-bfd-mpls, work in progress. [GMPLS-ASON] Papadimitriou, D., "OSPFv2 Routing Protocols Extensions for ASON Routing", work in progress, draft-ietf-ccamp-gmpls-ason-routing-ospf. Andersson, et al Informational [Page 38] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [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", draft-takacs-ccamp-revertive-ps, work in progress. [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. [RFC4655] A. Farrel, J.-P. Vasseur, and J. Ash, "A Path Computation Element (PCE) -Based Architecture", RFC4655, August 2006. [RFC5440] JP. Vasseur and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC5440, March 2009. [RFC4875] R. Aggarwal, D. Papadimitriou, and S. Yasukawa, "Extensions to Resource Reservation Protocol - Traffic Engineering (RSVP-TE) for Point-to-Multipoint TE Label Switched Paths (LSPs)", RFC4875, May 2007. [RFC3477] K. Kompella and Y. Rekhter, "Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)", RFC3477, January 2003. [RFC4201] K. Kompella and Y. Rekhter "Link Bundling in MPLS Traffic Engineering (TE)", RFC4201, October 2005. [RFC5145] K. Shiomoto, "Framework for MPLS-TE to GMPLS Migration" RFC5145, March 2008. [CCAMP-OAM-FWK] A. Takacs, D. Fedyk, and J. He, "OAM Configuration Framework and Requirements for GMPLS RSVP-TE" draft-ietf-ccamp-oam-configuration-fwk, work in progress. [CCAMP-OAM-EXT] Bellaganba, E., et.al., "RSVP-TE Extensions for MPLS-TP OAM Configuration", work in progress, draft-bellagamba-ccamp-rsvp-te-mpls-tp-oam-ext. Andersson, et al Informational [Page 39] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [HIERARCHY-BIS] Shiomoto, K, Ed., Farrel, A, Ed., "Procedures for Dynamically Signaled Hierarchical Label Switched Paths", draft-ietf-ccamp-lsp-hierarchy-bis, work in progress, October 2009. [TE-MIB] T Otani, et.al., "Traffic Engineering Database Management Information Base in support of MPLS-TE/GMPLS", draft-ietf-ccamp-gmpls-ted-mib, work in progress. [MS-PW-DYNAMIC] L. Martini, M Bocci, and F Balus "Dynamic Placement of Multi Segment Pseudo Wires", draft-ietf-pwe3-dynamic-ms-pw-10, work in progress, October 2009. [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 [PC-SCP] Caviglia, D, et al, "RSVP-TE Signaling Extension For The Conversion Between Permanent Connections And Soft Permanent Connections In A GMPLS Enabled Transport Network.", draft-ietf-ccamp-pc-spc-rsvpte-ext-07.txt, work in progress, February 2010. [SEGMENTED-PW] Martini, L., Nadeau, T., and Duckett M., "Segmented Pseaudowire", work in Progress, draft-ietf-pwe3-segmented-pw-13.txt, August 2009. [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. Andersson, et al Informational [Page 40] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [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. [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. [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. Andersson, et al Informational [Page 41] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [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. [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", RFC4802, Feb., 2007. [RFC4803] T. D. Nadeu and A. Farrel, "Generalized Multiprotocol Label Switching (GMPLS) Label Switching Router (LSR) Management Information Base", RFC4803, Feb., 2007. [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. [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV) : A Control Channel for Pseudowires", RFC 5085, December 2007. [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. [TP-RING] Weingarten, Y., Ed., "MPLS-TP Ring Protection", work in progress, draft-weingarten-mpls-tp-ring-protection. Andersson, et al Informational [Page 42] Internet-Draft draft-abfb-mpls-tp-control-plane-framework-02.txt February 22, 2010 [VCCV-BFD] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", draft-ietf-pwe3-vccv-bfd, work in progress. 11. 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 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 Andersson, et al Informational [Page 43] Generated on: Mon Feb 22 07:51:38 EST 2010