Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering
RFC 5623

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Network Working Group                                             E. Oki
Request for Comments: 5623          University of Electro-Communications
Category: Informational                                        T. Takeda
                                                                     NTT
                                                             JL. Le Roux
                                                          France Telecom
                                                               A. Farrel
                                                      Old Dog Consulting
                                                          September 2009

 Framework for PCE-Based Inter-Layer MPLS and GMPLS Traffic Engineering

Abstract

   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).

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright and License Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect

Oki, et al.                  Informational                      [Page 1]
RFC 5623        PCE-Based Inter-Layer MPLS and GMPLS TE   September 2009

   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.

Table of Contents

   1. Introduction ....................................................3
      1.1. Terminology ................................................3
   2. Inter-Layer Path Computation ....................................4
   3. Inter-Layer Path Computation Models .............................7
      3.1. Single PCE Inter-Layer Path Computation ....................7
      3.2. Multiple PCE Inter-Layer Path Computation ..................7
      3.3. General Observations ......................................10
   4. Inter-Layer Path Control .......................................10
      4.1. VNT Management ............................................10
      4.2. Inter-Layer Path Control Models ...........................11
           4.2.1. PCE-VNTM Cooperation Model .........................11
           4.2.2. Higher-Layer Signaling Trigger Model ...............13
           4.2.3. NMS-VNTM Cooperation Model .........................16
           4.2.4. Possible Combinations of Inter-Layer Path
                  Computation and Inter-Layer Path Control Models ....21
   5. Choosing between Inter-Layer Path Control Models ...............22
      5.1. VNTM Functions ............................................22
      5.2. Border LSR Functions ......................................23
      5.3. Complete Inter-Layer LSP Setup Time .......................24
      5.4. Network Complexity ........................................24
      5.5. Separation of Layer Management ............................25
   6. Stability Considerations .......................................25
   7. Manageability Considerations ...................................26
      7.1. Control of Function and Policy ............................27
           7.1.1. Control of Inter-Layer Computation Function ........27
           7.1.2. Control of Per-Layer Policy ........................27
           7.1.3. Control of Inter-Layer Policy ......................27
      7.2. Information and Data Models ...............................28
      7.3. Liveness Detection and Monitoring .........................28
      7.4. Verifying Correct Operation ...............................29
      7.5. Requirements on Other Protocols and Functional
           Components ................................................29