BGP BFD Strict-Mode
draft-merciaz-idr-bgp-bfd-strict-mode-02

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IDR WorkGroup                                                   M. Zheng
Internet-Draft                                                 A. Lindem
Intended status: Standards Track                           Cisco Systems
Expires: January 8, 2020                                         J. Haas
                                                  Juniper Networks, Inc.
                                                            July 7, 2019

                          BGP BFD Strict-Mode
                draft-merciaz-idr-bgp-bfd-strict-mode-02

Abstract

   This document specifies extensions to RFC4271 BGP-4 that enable a BGP
   speaker to negotiate additional Bidirectional Forwarding Detection
   (BFD) extensions using a BGP capability.  This BFD capability enables
   a BGP speaker to prevent a BGP session from being established until a
   BFD session is established.  It is referred to as BGP BFD "strict-
   mode".  BGP BFD strict-mode will be supported when both the local
   speaker and its remote peer are BFD strict-mode capable.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on January 8, 2020.

Copyright Notice

   Copyright (c) 2019 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
   (https://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

Zheng, et al.            Expires January 8, 2020                [Page 1]
Internet-Draft             BGP BFD Strict-Mode                 July 2019

   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
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  BFD Capability  . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Manageability Considerations  . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   5
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Bidirectional Forwarding Detection BFD [RFC5882] enables routers to
   monitor data plane connectivity and to detect faults in the
   bidirectional forwarding path between them.  This capability is
   leveraged by routing protocols such as BGP [RFC4271] to rapidly react
   to topology changes in the face of path failures.

   The BFD interaction with BGP is specified in Section 10.2 of
   [RFC5882].  When BFD is enabled for a BGP neighbor, faults in the
   bidirectional forwarding detected by BFD result in session
   termination.  It is possible in some failure scenarios for the
   network to be in a state such that a BGP session may be established
   but a BFD session cannot be established.  In some other scenarios, it
   may be possible to establish a BGP session, but a degraded or poor-
   quality link may result in the corresponding BFD session going up and
   down frequently.

   To avoid situations which result in routing churn and to minimize the
   impact of network interruptions, it will be beneficial to disallow
   BGP to establish a session until BFD session is successfully
   established and has stabilized.  We refer to this mode of operation
   as BGP BFD "strict-mode".  However, always using "strict-mode" would
   preclude BGP operation in an environment where not all routers
   support BFD strict-mode or have BFD enabled.  This document defines
   BGP "strict-mode" operation as preventing BGP session establishment
   until both the local and remove speakers have a stable BFD session.
   The document also specifies the BGP protocol extensions for BGP
   capability [RFC5492] for announcing BFD parameters including a BGP