Internet Engineering Task Force H. Stenn Internet-Draft D. Mills Intended status: Standards Track P. Prindeville Expires: January 3, 2019 Network Time Foundation July 2, 2018 Network Time Protocol: TCP Services draft-stenn-ntp-tcp-services-00 Abstract NTP was assigned port number 123 in 1985, in RFC 960. Traditionally, it has only used the UDP port as while UDP is useful for time synchronization, TCP is not suitable for time synchronization. UDP packet have length limits, and there are rate limits imposed by the protocol specification. Between the UDP packet length and rate limits, some other mechanism must be provided for efficient exchange of larger data packets. A TCP connection can be used for these uses. Additionally, we can perform better authentication and authorization checks using a TCP connection. 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 January 3, 2019. 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 Stenn, et al. Expires January 3, 2019 [Page 1] Internet-Draft Network Time Protocol TCP Services July 2018 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. NTP TCP Services . . . . . . . . . . . . . . . . . . . . . . 2 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 2 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. Normative References . . . . . . . . . . . . . . . . . . . . 3 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction NTP was assigned port number 123 in 1985, in RFC 960. The NTP protocol only uses UDP for its work, and UDP is an appropriate protocol for time synchronization. However, there are other needs for NTP, including monitoring and control, and ephemeral key exchange. For some of these cases, a TCP connection is much better. This specification describes a high-level framework for providing TCP services for NTP. 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. NTP TCP Services To provide NTP TCP Services, an NTP instance establishes communications with a TCP Listener. This could be a separate process or it could be part of the NTP daemon. Support STARTTLS. RFC 5705 [RFC5705] RFC 7301 [RFC7301] 3. IANA Considerations TBD Stenn, et al. Expires January 3, 2019 [Page 2] Internet-Draft Network Time Protocol TCP Services July 2018 4. Security Considerations Additional information TBD 5. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5705] Rescorla, E., "Keying Material Exporters for Transport Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705, March 2010, . [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, . [RFC5906] Haberman, B., Ed. and D. Mills, "Network Time Protocol Version 4: Autokey Specification", RFC 5906, DOI 10.17487/RFC5906, June 2010, . [RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan, "Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, July 2014, . Authors' Addresses Harlan Stenn Network Time Foundation P.O. Box 918 Talent, OR 97540 US Email: stenn@nwtime.org David L. Mills Network Time Foundation P.O. Box 918 Talent, OR 97540 US Email: mills@udel.edu Stenn, et al. Expires January 3, 2019 [Page 3] Internet-Draft Network Time Protocol TCP Services July 2018 Philip Prindeville Network Time Foundation P.O. Box 918 Talent, OR 97540 US Email: prindeville@ntp.org Stenn, et al. Expires January 3, 2019 [Page 4]