Label Switched Path (LSP) Self-Ping
RFC 7746

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Internet Engineering Task Force (IETF)                         R. Bonica
Request for Comments: 7746                              Juniper Networks
Category: Standards Track                                       I. Minei
ISSN: 2070-1721                                             Google, Inc.
                                                                 M. Conn
                                                              D. Pacella
                                                             L. Tomotaki
                                                                 Verizon
                                                            January 2016

                  Label Switched Path (LSP) Self-Ping

Abstract

   When certain RSVP-TE optimizations are implemented, ingress Label
   Switching Router (LSRs) can receive RSVP RESV messages before
   forwarding state has been installed on all downstream nodes.
   According to the RSVP-TE specification, the ingress LSR can forward
   traffic through a Label Switched Path (LSP) as soon as it receives a
   RESV message.  However, if the ingress LSR forwards traffic through
   the LSP before forwarding state has been installed on all downstream
   nodes, traffic can be lost.

   This document describes LSP Self-ping.  When an ingress LSR receives
   an RESV message, it can invoke LSP Self-ping procedures to ensure
   that forwarding state has been installed on all downstream nodes.

   LSP Self-ping is a new protocol.  It is not an extension of LSP Ping.
   Although LSP Ping and LSP Self-ping are named similarly, each is
   designed for a unique purpose.  Each protocol listens on its own UDP
   port and executes its own procedures.

   LSP Self-ping is an extremely lightweight mechanism.  It does not
   consume control-plane resources on transit or egress LSRs.

Bonica, et al.               Standards Track                    [Page 1]
RFC 7746                      LSP Self-Ping                 January 2016

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.
   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7746.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Applicability . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The LSP Self-ping Message . . . . . . . . . . . . . . . . . .   6
   4.  LSP Self-Ping Procedures  . . . . . . . . . . . . . . . . . .   7
   5.  Bidirectional LSP Procedures  . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Appendix A.  Rejected Approaches  . . . . . . . . . . . . . . . .  11
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  11
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

Bonica, et al.               Standards Track                    [Page 2]
RFC 7746                      LSP Self-Ping                 January 2016

1.  Introduction

   Ingress Label Switching Routers (LSRs) use RSVP-TE [RFC3209] to
   establish MPLS Label Switched Paths (LSPs).  The following paragraphs
   describe RSVP-TE procedures.

   The ingress LSR calculates a path between itself and an egress LSR.
   The calculated path can be either strictly or loosely routed.  Having
   calculated a path, the ingress LSR constructs an RSVP PATH message.
   The PATH message includes an Explicit Route Object (ERO) that