Internet Engineering Task Force O.E.J. Johansson, Ed. Internet-Draft Edvina AB Intended status: Standards Track 24 August 2021 Expires: 25 February 2022 TLS ALPN usage in the Session Initiation Protocol (SIP) draft-johansson-sip-alpn-02 Abstract Many SIP specifications use other protocols in addition to the core SIP protocol, like HTTP and MSRP. In order to be able to use multiple protocols on the same port with TLS, a TLS Application Protocol Negotiation Extension (ALPN) protocol ID is needed (RFC 7301 [RFC7301]). This document registers "sip/2" as the ALPN protocol ID for the SIP protocol version 2.0. 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 25 February 2022. Copyright Notice Copyright (c) 2021 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. Johansson Expires 25 February 2022 [Page 1] Internet-Draft ALPN usage for SIP August 2021 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. ALPN registration . . . . . . . . . . . . . . . . . . . . . . 2 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 2 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 2 5. Security Considerations . . . . . . . . . . . . . . . . . . . 2 6. Normative References . . . . . . . . . . . . . . . . . . . . 3 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction A modern SIP server not only supports the Session Initation Protocol v2.0 (RFC 3261 [RFC3261]), but also needs to support HTTP and possibly other related protocols, like MSRP. To reduce the number of ports used, a SIP server supporting Transport Layer Security (TLS) can support multiple protocols on the same port, provided the clients signal protocol usage with ALPN. 2. ALPN registration Registration following the specification in RFC 7301 [RFC7301] * Protocol: SIP * Identification Sequence: 0x73 0x69 0x70 0x2f 0x32 ("sip/2") * Reference: RFC 3261 3. Acknowledgements This document was inspired by registration feedback from Rich Salz. 4. IANA Considerations This document registres a new ALPN in the "Application-Layer Protocol Negotiation (ALPN) Protocol IDs" registry under the existing "Transport Layer Security (TLS) Extensions" heading. 5. Security Considerations This document modifies the behaviour of compliant SIP servers when being used by compliant SIP implementations (servers and clients). It does not add any known security issues to the protocol. For security considerations related to usage of ALPN in TLS, see RFC 7301 [RFC7301] Johansson Expires 25 February 2022 [Page 2] Internet-Draft ALPN usage for SIP August 2021 6. Normative References [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, June 2002, . [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, . Author's Address Olle E. Johansson (editor) Edvina AB Sollentuna Sweden Phone: +46 8 5000 1625 Email: oej@edvina.net Johansson Expires 25 February 2022 [Page 3]