Network Working Group H. Kaplan Internet Draft Acme Packet Intended status: Informational R. Walter Expires: April 24, 2012 NetNumber P. Gorman Sprint Nextel M. Maharishi TNS October 24, 2011 EDNS Option Code for SIP and PSTN Source Reference Info draft-kaplan-dnsext-enum-sip-source-ref-opt-code-03 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 24, 2012. Copyright and License Notice Copyright (c) 2010 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 (http://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 Kaplan Expires April 2011 [Page 1] Internet-Draft EDNS Option Code for SIP Source October 2011 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 BSD License. Abstract This document requests an IANA allocation for an EDNS0 Option-Code, per [RFC2671], for a UTF-8 encoded string field containing a URI for private use. The intended use of this field is for providing SIP and PSTN-type source information for ENUM-resolution DNS queries, in private DNS server environments such as Private ENUM. Table of Contents 1. Introduction..................................................2 2. Terminology...................................................3 3. Applicability.................................................3 4. OPTION-DATA Format............................................3 5. Security Considerations.......................................3 6. IANA Considerations...........................................4 7. Acknowledgments...............................................4 8. References....................................................4 8.1. Normative References.....................................4 8.2. Informative References...................................4 Authors' Addresses................................................4 1. Introduction In many VoIP domains, private DNS servers are used to provide ENUM resolution for SIP request routing purposes. Devices in such domains, such as SIP Proxies and PSTN Gateways, which are the DNS clients set to use the private DNS servers for ENUM resolution, need to provide the server(s) with some additional private meta-data concerning the source of the SIP request that triggered the DNS query, which may aid the server(s) in providing an answer. The additional data is in the form of a URI-formatted UTF-8 string, which needs to be provided in the DNS query request. The Extension Mechanism for DNS (EDNS) defined in [RFC2671] provides a suitable means by which to encode such a string into the DNS request, using the OPT RR and a new EDNS0 Option-Code indicating this field use. This document requests IANA for assignment of such an Option-Code, for providing SIP and PSTN-type source reference information in DNS requests used for ENUM, in private, controlled environments only. This is neither applicable to, nor appropriate for, the general public Internet DNS; the only reason this document exists is to Kaplan, et al Expires - April 2011 [Page 2] Internet-Draft EDNS Option Code for SIP Source October 2011 obtain a reserved option code number, for interoperability among vendors within private, restricted environments. 2. Terminology 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. The terminology in this document conforms to RFC 2828, "Internet Security Glossary". Private DNS server: a DNS server which does not use the IANA-base tree, nor the "e164.arpa" suffix, and is deployed for specific name resolution purposes in a controlled, restricted environment. 3. Applicability This draft requests a new Option code value based on [EDNS0]. 4. OPTION-DATA Format The format of the OPTION-DATA contents is a UTF-8 [RFC2279] text string, with no character termination (the OPTION-LENGTH field identifies the length). For the private use defined for this option code, the contents of the UTF-8 string are a URI, typically a SIP or TEL URI, including the "sip:" or "tel:" schemes. Non-UTF-8 characters, or characters not allowed in the ABNF rules for a SIP-URI or TEL-URI format per [RFC3261] or [RFC3966] MUST be escaped per those formats. The usage and source of the URI content is outside the scope of this document, and are documented in [draft-enum-sip-routing]. The query option is of a multi-hop, transitive nature. As such, this mechanism will only work in restricted DNS server use cases where all the DNS servers (and intermediate caches) are known to support the extension. The primary use-case for this is in Private ENUM deployments. 5. Security Considerations There are privacy concerns with regard to passing SIP/PSTN source reference information in a DNS query. The intent of this option is for a purely private use, in a controlled environment. Clients MUST NOT use this option mechanism if they do not know the DNS query will only be processed by private DNS servers in a controlled environment, for example through explicit configuration that such is the case. Kaplan, et al Expires - April 2011 [Page 3] Internet-Draft EDNS Option Code for SIP Source October 2011 6. IANA Considerations This document requests that IANA register in the "Domain Name System (DNS) Parameters" registry at http://www.iana.org/assignments/dns- parameters in sub-registry "DNS EDNS0 Options", a new option named "SIP/PSTN Source Reference Info". 7. Acknowledgments Thanks to Tom Creighton (Comcast), James Yu (Neustar), Nick Russell (Vodafone), Colin Pons (KPN), and Raja Gopal (Nominum) for their input and support. Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). 8. References 8.1. Normative References [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998. [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC 2671, August 1999. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966, December 2004. 8.2. Informative References [draft-enum-sip-routing] Kaplan, H., Pons, C., Gorman, P., "Routing SIP Requests with ENUM", draft-kaplan-enum-sip-routing-04, October 24, 2011. Authors' Addresses Hadriel Kaplan Acme Packet 100 Crosby Dr. Bedford, MA 01730 USA Email: hkaplan@acmepacket.com Robert H. Walter NetNumber, Inc. Kaplan, et al Expires - April 2011 [Page 4] Internet-Draft EDNS Option Code for SIP Source October 2011 650 Suffolk Street, Suite 307 Lowell, MA 01854 USA Email: rwalter@netnumber.com Pierce Gorman Sprint Nextel Corporation 6220 Sprint Parkway MS: KSOPHD0504 - 5D208 Overland Park, KS 66251 Email: pierce.gorman@sprint.com Manjul Maharishi TNS Inc. 1939 Roland Clarke Place Reston, VA 20191 USA Email: mmaharishi@tnsi.com Kaplan, et al Expires - April 2011 [Page 5]