TLS ALPN usage in the Session Initiation Protocol (SIP)
draft-johansson-sip-alpn-02

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

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   This Internet-Draft will expire on 25 February 2022.

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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]

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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,
              <https://www.rfc-editor.org/info/rfc3261>.

   [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, <https://www.rfc-editor.org/info/rfc7301>.

Author's Address

   Olle E. Johansson (editor)
   Edvina AB
   Sollentuna
   Sweden

   Phone: +46 8 5000 1625
   Email: oej@edvina.net

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