"Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering", Eiji Oki, Tomonori Takeda, Jean-Louis Le Roux, Adrian Farrel, 26-Mar-09. ( bytes)

A network may comprise multiple layers. It is important to globally optimize network resource utilization, taking into account all layers, rather than optimizing resource utilization at each layer independently. This allows better network efficiency to be achieved through a process that we call inter-layer traffic engineering. The Path Computation Element (PCE) can be a powerful tool to achieve inter-layer traffic engineering. This document describes a framework for applying the PCE-based architecture to inter-layer Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) traffic engineering. It provides suggestions for the deployment of PCE in support of multi-layer networks. This document also describes network models where PCE performs inter-layer traffic engineering, and the relationship between PCE and a functional component called the Virtual Network Topology Manager (VNTM).

"Definitions of Textual Conventions for Path Computation Element", Emile Stephan, 4-Mar-09. ( bytes)

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it defines Textual Conventions to represent commonly used Path Computation Element (PCE) management information. The intent is that these TEXTUAL CONVENTIONS (TCs) will be imported and used in PCE related MIB modules to avoid duplicating conventions.

"Inclusion of Manageability Sections in PCE Working Group Drafts", Adrian Farrel, 27-Jul-09. ( bytes)

It has often been the case that manageability considerations have been retrofitted to protocols after they have been specified, standardized, implemented, or deployed. This is sub-optimal. Similarly, new protocols or protocol extensions are frequently designed without due consideration of manageability requirements. This document specifies the recommendation for all new Internet-Drafts in the PCE Working Group to include a "Manageability Considerations" section, and gives guidance on what that section should contain.

"A set of monitoring tools for Path Computation Element based Architecture", JP Vasseur, Jean-Louis Le Roux, Yuichi Ikejiri, 12-Jun-09. ( bytes)

A Path Computation Element (PCE) based architecture has been specified for the computation of Traffic Engineering (TE) Label Switched Paths (LSPs) in Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks in the context of single or multiple domains (where a domain refers to a collection of network elements within a common sphere of address management or path computational responsibility such as IGP areas and Autonomous Systems). Path Computation Clients (PCCs) send computation requests to PCEs, and these may forward the requests to and cooperate with other PCEs forming a "path computation chain". In PCE-based environments, it is thus critical to monitor the state of the path computation chain for troubleshooting and performance monitoring purposes: liveness of each element (PCE) involved in the PCE chain, detection of potential resource contention states and statistics in term of path computation times are examples of such metrics of interest. This document specifies procedures and extensions to the Path Computation Element Protocol (PCEP) in order to gather such information.

"Applicability of the Path Computation Element (PCE) to Point-to-Multipoint (P2MP) Multiprotocol Label Switching (MPLS)and Generalized MPLS (GMPLS) Traffic Engineering (TE)", Seisho Yasukawa, Adrian Farrel, 13-Feb-09. ( bytes)

The Path Computation Element (PCE) provides path computation functions in support of traffic engineering in Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. Extensions to the MPLS and GMPLS signaling and routing protocols have been made in support of point-to-multipoint (P2MP) Traffic Engineered (TE) Label Switched Paths (LSPs). This document examines the applicability of PCE to path computation for P2MP TE LSPs in MPLS and GMPLS networks. It describes the motivation for using a PCE to compute these paths, and examines which of the PCE architectural models are appropriate.

"PCC-PCE Communication Requirements for Point to Multipoint Multiprotocol Label Switching Traffic Engineering (MPLS-TE)", Seisho Yasukawa, Adrian Farrel, 13-Feb-09. ( bytes)

The Path Computation Element (PCE) provides path computation functions in support of traffic engineering in Multi-Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. Extensions to the MPLS and GMPLS signaling and routing protocols have been made in support of point-to-multipoint (P2MP) Traffic Engineered (TE) Label Switched Paths (LSPs). The use of PCE in MPLS networks is already established, and since P2MP TE LSP routes are sometimes complex to compute, it is likely that PCE will be used for P2MP LSPs. Generic requirements for a communication protocol between Path Computation Clients (PCCs) and PCEs are presented in "Path Computation Element (PCE) Communication Protocol Generic Requirements". This document complements the generic requirements and presents a detailed set of PCC-PCE communication protocol requirements for point-to-multipoint MPLS/GMPLS traffic engineering.

"Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths", Quintin Zhao, Daniel King, Fabien Verhaeghe, Tomonori Takeda, Zafar Ali, Julien Meuric, Jean-Louis Le Roux, Mohamad Chaitou, 13-Jul-09. ( bytes)

Point-to-point Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering Label Switched Paths (TE LSPs) may be established using signaling techniques, but their paths may first be determined. The Path Computation Element (PCE) has been identified as an appropriate technology for the determination of the paths of P2MP TE LSPs. This document describes extensions to the PCE communication Protocol (PCEP) to handle requests and responses for the computation of paths for P2MP TE LSPs.

"Document: draft-ietf-pce-gmpls-aps-req-01.txt", Tomohiro Otani, Kenichi Ogaki, Diego Caviglia, Fatai Zhang, 8-Jul-09. ( bytes)

The initial effort of PCE WG is specifically focused on MPLS (Multi- protocol label switching). As a next step, this draft describes functional requirements for GMPLS (Generalized MPLS) application of PCE (Path computation element).

"The use of SVEC (Synchronization VECtor) list for Synchronized dependent path computations", Itaru Nishioka, Daniel King, 9-Mar-09. ( bytes)

A Path Computation Element (PCE) performing dependent path computations, for instance calculating a diverse working and protected path do not share common network points, would need to synchronize the computations in order to increase the probability of meeting the working and protected path disjoint objective and network resource optimization objective. When a PCE computes multiple sets of dependent path computation requests concurrently, it is required to use Synchronization VECtor (SVEC) list for association among the sets of dependent path computation requests. SVEC is also applicable to end-to-end diverse path computation across multiple domains. This document describes the usage of SVECs in the SVEC list and diverse path computation guideline, for the synchronized computation of dependent paths.

"PCC-PCE Communication Requirements for VPNs", Seisho Yasukawa, Adrian Farrel, 24-Mar-09. ( bytes)

The Path Computation Element (PCE) provides path computation functions in support of traffic engineering in Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. An important application of MPLS and GMPLS networks is Virtual Private Networks (VPNs) that may be constructed using Label Switched Paths (LSPs) in the MPLS and GMPLS networks as VPN tunnels. PCE may be applied as a tool to compute the paths of such tunnels in order to achieve better use of the network resources and to provide better levels of service to the VPN customers. Generic requirements for a communication protocol between Path Computation Clients (PCCs) and PCEs are presented in "Path Computation Element (PCE) Communication Protocol Generic Requirements". This document complements the generic requirements and presents a detailed set of PCC-PCE communication protocol requirements that are specific to the application of PCE to VPNs.

"Conveying Vendor-Specific Constraints in the Path Computation Element Protocol", Adrian Farrel, Greg Bernstein, 27-Jul-09. ( bytes)

The Path Computation Element Protocol (PCEP) is used to convey path computation requests and responses between Path Computation Clients (PCCs) and Path Computation Elements (PCEs), and also between cooperating PCEs. In PCEP the path computation requests carry details of the constraints and objective functions that the PCC wishes the PCE to apply in its computation. The mechanisms defined for indicating objective functions include the capability to convey vendor-specific objective functions. This document defines a facility to carry vendor-specific constraints in PCEP.

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