Signaling RSVP-TE tunnels on a shared MPLS forwarding plane
draft-sitaraman-mpls-rsvp-shared-labels-02

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MPLS Working Group                                          H. Sitaraman
Internet-Draft                                                 V. Beeram
Intended status: Standards Track                        Juniper Networks
Expires: March 10, 2018                                        T. Parikh
                                                                 Verizon
                                                                 T. Saad
                                                           Cisco Systems
                                                       September 6, 2017

      Signaling RSVP-TE tunnels on a shared MPLS forwarding plane
             draft-sitaraman-mpls-rsvp-shared-labels-02.txt

Abstract

   As the scale of MPLS RSVP-TE networks has grown, so the number of
   Label Switched Paths (LSPs) supported by individual network elements
   has increased.  Various implementation recommendations have been
   proposed to manage the resulting increase in control plane state.

   However, those changes have had no effect on the number of labels
   that a transit Label Switching Router (LSR) has to support in the
   forwarding plane.  That number is governed by the number of LSPs
   transiting or terminated at the LSR and is directly related to the
   total LSP state in the control plane.

   This document defines a mechanism to prevent the maximum size of the
   label space limit on an LSR from being a constraint to control plane
   scaling on that node.  That is, it allows many more LSPs to be
   supported than there are forwarding plane labels available.

   This work introduces the notion of pre-installed 'pop labels' that
   are applied per Traffic Engineering link and that can be shared by
   MPLS RSVP-TE LSPs that traverse these links.  This approach
   significantly reduces the forwarding plane state required to support
   a large number of LSPs.  This couples the feature benefits of the
   RSVP-TE control plane with the simplicity of the Segment Routing MPLS
   forwarding plane.

   This document also introduces the ability to mix different types of
   label operations along the path of an LSP, thereby allowing the
   ingress router or an external controller to influence how to
   optimally place a LSP in the network.

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Requirements Language

   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].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on March 10, 2018.

Copyright Notice

   Copyright (c) 2017 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Allocation of Pop Labels  . . . . . . . . . . . . . . . . . .   5
   4.  RSVP-TE Pop and Forward Tunnel Setup  . . . . . . . . . . . .   5
   5.  Delegating Label Stack Imposition . . . . . . . . . . . . . .   7
     5.1.  Stacking at the Ingress . . . . . . . . . . . . . . . . .   8
       5.1.1.  Stack to Reach Delegation Hop . . . . . . . . . . . .   8
       5.1.2.  Stack to Reach Egress . . . . . . . . . . . . . . . .   9

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