Internet Engineering Task Force H. Stenn Internet-Draft Network Time Foundation Intended status: Standards Track February 21, 2018 Expires: August 25, 2018 Network Time Protocol Extended Information Extension Field draft-stenn-ntp-extended-information-02 Abstract The network packet format used by NTP has changed very little between NTPv1, defined by RFC 958 [RFC0958] in 1985, and NTPv4, defined by RFC 5905 [RFC5905]. The core network packet used by NTP has no spare bits available for reporting additional state information and no larger data areas available for larger amounts of information. This proposal offers a new extension field that would contains this additional information. 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 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 August 25, 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 (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 Stenn Expires August 25, 2018 [Page 1] Internet-Draft Network Time Protocol Extended Information February 2018 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 Extended Information Extension Field . . . . . . . . . . 2 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Normative References . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction The core NTP packet format has changed little since RFC 958 [RFC0958] was published in 1985. Since then, there has been demonstrated need to convey additional information about NTP's state in an NTP packet, but no backward-compatible way to usurp the few otherwise potentially available bits has been found, and no larger data areas are available in the core packet structure. This proposal offers a new extension field that would contain this additional information. 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 Extended Information Extension Field The Field Type of the Extended Information EF includes a version specification, to make it easier to evolve this specification. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +---------------+---------------+-------------------------------+ | Field Type | Field Length | +-------------------------------+-------------------------------+ | Content Descriptor 1 | Content Data 1 | +---------------------------------------------------------------+ NTP Extension Field: Extended Information Field Type: TBD (Recommendation for IANA: 0x0009 (Extended- Information), 0x0109 (Extended-Information Version 1) Stenn Expires August 25, 2018 [Page 2] Internet-Draft Network Time Protocol Extended Information February 2018 Field Length: as needed Payload: For Version 1, a two octet Content Descriptor field and a two octet Content Data field, as described below. Version 1 Content fields. Content Descriptor 1 Content Data 1 0x0001 TAI offset in the low-order 8 bits, 24-31 0x0002 Interleave Mode indicator in Bit 23 0xFFFD Reserved (Zeroes) Interleave Mode: 1 if the sender is in interleave mode, 0 otherwise NTP Extension Field: Extended Information Version 1 Content Fields Example: A system that wants to convey an offset to TAI of 36 seconds, and show it is in interleave mode. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +---------------+---------------+-------------------------------+ | Field Type (0x0109) | Field Length (0x0008) | +-------------------------------+-------------------------------+ | 0x0003 | 0x0124 | +-------------------------------+-------------------------------+ NTP Extension Field: Extended Information V1, Example 3. Acknowledgements The author wishes to acknowledge the contributions of Martin Burnicki. 4. IANA Considerations This memo requests IANA to allocate NTP Extension Field Types 0x0009 (Extended-Information) 0x0109 (Extended-Information Version 1) for this proposal. Stenn Expires August 25, 2018 [Page 3] Internet-Draft Network Time Protocol Extended Information February 2018 5. Security Considerations Additional information TBD 6. Normative References [RFC0958] Mills, D., "Network Time Protocol (NTP)", RFC 958, DOI 10.17487/RFC0958, September 1985, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, . Author's Address Harlan Stenn Network Time Foundation P.O. Box 918 Talent, OR 97540 US Email: stenn@nwtime.org Stenn Expires August 25, 2018 [Page 4]