Bidirectional Forwarding Detection (BFD) for Virtual eXtensible Local Area Network (VXLAN)
RFC 8971

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Internet Engineering Task Force (IETF)                S. Pallagatti, Ed.
Request for Comments: 8971                                        VMware
Category: Informational                                   G. Mirsky, Ed.
ISSN: 2070-1721                                                ZTE Corp.
                                                             S. Paragiri
                                                  Individual Contributor
                                                             V. Govindan
                                                            M. Mudigonda
                                                                   Cisco
                                                           December 2020

 Bidirectional Forwarding Detection (BFD) for Virtual eXtensible Local
                          Area Network (VXLAN)

Abstract

   This document describes the use of the Bidirectional Forwarding
   Detection (BFD) protocol in point-to-point Virtual eXtensible Local
   Area Network (VXLAN) tunnels used to form an overlay network.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are candidates for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8971.

Copyright Notice

   Copyright (c) 2020 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
   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.  Conventions Used in This Document
     2.1.  Abbreviations
     2.2.  Requirements Language
   3.  Deployment
   4.  Use of the Management VNI
   5.  BFD Packet Transmission over VXLAN Tunnel
   6.  Reception of BFD Packet from VXLAN Tunnel
   7.  Echo BFD
   8.  IANA Considerations
   9.  Security Considerations
   10. References
     10.1.  Normative References
     10.2.  Informative References
   Acknowledgments
   Contributors
   Authors' Addresses

1.  Introduction

   "Virtual eXtensible Local Area Network (VXLAN)" [RFC7348] provides an
   encapsulation scheme that allows the building of an overlay network
   by decoupling the address space of the attached virtual hosts from
   that of the network.

   One use of VXLAN is in data centers interconnecting virtual machines
   (VMs) of a tenant.  VXLAN addresses the requirements of the Layer 2
   and Layer 3 data-center network infrastructure in the presence of VMs
   in a multi-tenant environment by providing a Layer 2 overlay scheme
   on a Layer 3 network [RFC7348].  Another use is as an encapsulation
   for Ethernet VPN [RFC8365].

   This document is written assuming the use of VXLAN for virtualized
   hosts and refers to VMs and VXLAN Tunnel End Points (VTEPs) in
   hypervisors.  However, the concepts are equally applicable to non-
   virtualized hosts attached to VTEPs in switches.

   In the absence of a router in the overlay, a VM can communicate with
   another VM only if they are on the same VXLAN segment.  VMs are
   unaware of VXLAN tunnels, because a VXLAN tunnel is terminated on a
   VTEP.  VTEPs are responsible for encapsulating and decapsulating
   frames exchanged among VMs.

   The ability to monitor path continuity -- i.e., perform proactive
   continuity check (CC) for point-to-point (p2p) VXLAN tunnels -- is
   important.  The asynchronous mode of BFD, as defined in [RFC5880], is
   used to monitor a p2p VXLAN tunnel.

   In the case where a Multicast Service Node (MSN) (as described in
   Section 3.3 of [RFC8293]) participates in VXLAN, the mechanisms
   described in this document apply and can, therefore, be used to test
   the continuity of the path between the source Network Virtualization
   Endpoint (NVE) and the MSN.

   This document describes the use of the Bidirectional Forwarding
   Detection (BFD) protocol to enable monitoring continuity of the path
   between VXLAN VTEPs that are performing as VNEs, and/or between the
   source NVE and a replicator MSN using a Management VXLAN Network