BFD Encapsulated in Large Packets
draft-haas-bfd-large-packets-01

Document Type Active Internet-Draft (candidate for bfd WG)
Last updated 2018-10-18 (latest revision 2018-10-16)
Stream IETF
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream WG state Call For Adoption By WG Issued
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                            J. Haas
Internet-Draft                                    Juniper Networks, Inc.
Intended status: Standards Track                                   A. Fu
Expires: April 19, 2019                                        Bloomberg
                                                        October 16, 2018

                   BFD Encapsulated in Large Packets
                    draft-haas-bfd-large-packets-01

Abstract

   The Bidirectional Forwarding Detection (BFD) protocol is commonly
   used to verify connectivity between two systems.  BFD packets are
   typically very small.  It is desirable in some circumstances to know
   that not only is the path between two systems reachable, but also
   that it is capable of carrying a payload of a particular size.  This
   document discusses thoughts on how to implement such a mechanism
   using BFD in Asynchronous mode.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
   be interpreted as described in [RFC2119] only when they appear in all
   upper case.  They may also appear in lower or mixed case as English
   words, without normative meaning.

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 April 19, 2019.

Haas & Fu                Expires April 19, 2019                 [Page 1]
Internet-Draft      BFD Encapsulated in Large Packets       October 2018

Copyright Notice

   Copyright (c) 2018 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  BFD Encapsulated in Large Packets . . . . . . . . . . . . . .   3
   3.  Implementation and Deployment Considerations  . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The Bidirectional Forwarding Detection (BFD) [RFC5880] protocol is
   commonly used to verify connectivity between two systems.  However,
   some applications may require that the Path MTU [RFC1191] between
   those two systems meets a certain minimum criteria.  When the Path
   MTU decreases below the minimum threshold, those applications may
   wish to consider the path unusable.

   BFD may be encapsulated in a number of transport protocols.  An
   example of this is single-hop BFD [RFC5881].  In that case, the link
   MTU configuration is typically enough to guarantee communication
   between the two systems for that size MTU.  BFD Echo mode
   (Section 6.4 of [RFC5880]) is sufficient to permit verification of
   the Path MTU of such directly connected systems.  Previous proposals
   ([I-D.haas-xiao-bfd-echo-path-mtu]) have been made for testing Path
   MTU for such directly connected systems.  However, in the case of
   multi-hop BFD [RFC5883], this guarantee does not hold.

   The encapsulation of BFD in multi-hop sessions is a simple UDP
   packet.  The BFD elements of procedure (Section 6.8.6 of [RFC5880])

Haas & Fu                Expires April 19, 2019                 [Page 2]
Internet-Draft      BFD Encapsulated in Large Packets       October 2018

   covers validating the BFD payload.  However, the specification is
   silent on the length of the encapsulation that is carrying the BFD
   PDU.  While it is most common that the transport protocol payload
Show full document text