Network Time Protocol I-Do Extension Field
draft-stenn-ntp-i-do-06

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Internet Engineering Task Force                                 H. Stenn
Internet-Draft                                   Network Time Foundation
Intended status: Standards Track                          March 25, 2019
Expires: September 26, 2019

               Network Time Protocol I-Do Extension Field
                        draft-stenn-ntp-i-do-06

Abstract

   This proposal defines and describes a mechanism by which cooperating
   NTP instances may communicate any optional features they are willing
   to admit they support.

   RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH BEFORE PUBLISHING:

   The source code and issues list for this draft can be found in
   https://github.com/hstenn/ietf-ntp-i-do

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
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   Drafts is at https://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 September 26, 2019.

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
   to this document.  Code Components extracted from this document must

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   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.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  The I-Do Extension Field  . . . . . . . . . . . . . . . . . .   2
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  I-DO Packet Format  . . . . . . . . . . . . . . . . . . .   4
     2.3.  Behavior  . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The first implementation of NTPv4 was released in 2003, and was
   defined by RFC 5905 [RFC5905].  It contains an optional and now
   obsolete public-key security protocol, Autokey, which is defined by
   RFC 5906 [RFC5906].  Until very recently, Autokey has been the only
   implemented use of NTP packet Extension Fields.  New proposals for
   extension fields are being written and there is currently no
   convenient way to learn if a remote instance of NTP supports any
   extension fields or not.  This proposal contains a method to tell a
   remote instance of NTP what we (are willing to admit we) support, and
   ask what they (are willing to admit they) support.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  The I-Do Extension Field

2.1.  Overview

   The purpose of the I-DO EF is to provide information to the remote
   side about our capabilities.

   If an incoming packet contains an unrecognized extension field, one
   of several things will happen.  While that unrecognized extension

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   field SHOULD be ignored, an implementation MAY choose to drop the
   entire packet.

   If any extension field is present there ordinarily SHOULD be a MAC
   following the extension field.  However, an older conforming NTP
   implementation will require that any EF MUST be followed by a MAC.

   Some extension fields are unable to be "signed" by a MAC, regardless