Label Switched Path (LSP) Self-Ping
RFC 7746
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
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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
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