Bidirectional Forwarding Detection (BFD) Directed Return Path
draft-ietf-mpls-bfd-directed-07
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draft-mirsky-mpls-bfd-directed
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"Martin Vigoureux" <martin.vigoureux@nokia.com>, loa@pi.nu, "Nicolai Leymann" <n.leymann@telekom.de>
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MPLS Working Group G. Mirsky
Internet-Draft ZTE
Intended status: Standards Track J. Tantsura
Expires: December 15, 2017 Individual
I. Varlashkin
Google
M. Chen
Huawei
June 13, 2017
Bidirectional Forwarding Detection (BFD) Directed Return Path
draft-ietf-mpls-bfd-directed-07
Abstract
Bidirectional Forwarding Detection (BFD) is expected to be able to
monitor wide variety of encapsulations of paths between systems.
When a BFD session monitors an explicitly routed unidirectional path
there may be a need to direct egress BFD peer to use a specific path
for the reverse direction of the BFD session.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 15, 2017.
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
Mirsky, et al. Expires December 15, 2017 [Page 1]
Internet-Draft BFD Directed Return Path June 2017
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 . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 3
1.1.1. Requirements Language . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. Control of the Reverse BFD Path . . . . . . . . . . . . . . . 3
3.1. BFD Reverse Path TLV . . . . . . . . . . . . . . . . . . 3
3.2. Static and RSVP-TE sub-TLVs . . . . . . . . . . . . . . . 4
3.3. Return Codes . . . . . . . . . . . . . . . . . . . . . . 5
4. Use Case Scenario . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. BFD Reverse Path TLV . . . . . . . . . . . . . . . . . . 5
5.2. Return Code . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Normative References . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[RFC5880], [RFC5881], and [RFC5883] established the BFD protocol for
IP networks. [RFC5884] and [RFC7726] set rules of using BFD
asynchronous mode over IP/MPLS LSPs. These standards implicitly
assume that the egress BFD peer will use the shortest path route
regardless of route being used to send BFD control packets towards
it.
For the case where a LSP is explicitly routed it is likely that the
shortest return path to the ingress BFD peer would not follow the
same path as the LSP in the forward direction. The fact that BFD
control packets are not guaranteed to follow the same links and nodes
in both forward and reverse directions is a significant factor in
producing false positive defect notifications, i.e. false alarms, if
used by the ingress BFD peer to deduce the state of the forward
direction.
This document defines the BFD Reverse Path TLV as an extension to LSP
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