One document matched: draft-livingood-shockey-enum-npd-00.txt

ENUM Working Group                                         J. Livingood 
Internet-Draft                             Comcast Cable Communications 
Expires: January 8, 2006                                     R. Shockey 
                                                                NeuStar 
                                                              July 2005 
    
    
                   IANA Registration for an Enumservice 
       Containing Number Portability and PSTN Signaling Information 
                    draft-livingood-shockey-enum-npd-00 
    
    
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Copyright Notice 
    
   Copyright (C) The Internet Society (2005). 
    
    
Abstract 
    
   This document registers the Enumservice ônpdö and subtype ôtelö using 
   the URI scheme ætel:Æ as per the IANA registration process defined in 
   the ENUM specification, RFC 3761.  This data is used to facilitate 
   the routing of telephone calls in those countries where Number 
   Portability exists. 
 
 
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Table of Contents 
    
   1. Terminology....................................................2 
   2. Introduction...................................................2 
   3. ENUM Service Registration for NPD..............................3 
   4. Examples.......................................................4 
      4.1 Example of a Ported Telephone Number.......................4 
      4.2 Example of a Non-Ported Telephone Number...................4 
   5. Security Considerations........................................5 
   6. IANA Considerations............................................5 
   7. Acknowledgements...............................................5 
   8. References.....................................................6 
      8.1 Normative References.......................................6 
      8.2 Informative References.....................................6 
   AuthorsÆ Addresses................................................7 
   Intellectual Property and Copyright Statements....................7 
    
    
1. 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 BCP 14, RFC-2119 [1]. 
    
2. Introduction 
    
   ENUM (E.164 Number Mapping, RFC 3761 [1]) is a system that transforms 
   E.164 numbers (The International Public Telecommunication Number 
   Plan, ITU-T Recommendation E.164 [2]) into domain names and then uses 
   DNS (Domain Name Service, RFC 1034 [3]) delegation through NS records 
   and NAPTR records (Dynamic Delegation Discovery System (DDDS) Part 
   Three: The Domain Name System (DNS) Database, RFC 3403 [4]) to look 
   up what services are available for a specific domain name. 
    
   This document registers Enumservices according to the guidelines 
   given in RFC 3761 [1] to be used for provisioning in the services 
   field of a NAPTR [4] resource record to indicate the type of 
   functionality associated with an end point and/or telephone number.  
   The registration is defined within the DDDS (Dynamic Delegation 
   Discovery System [4][5][6][7][8]) hierarchy, for use with the "E2U" 
   DDDS Application defined in RFC 3761. 
    
   Number portability (NP) allows telephone subscribers to keep their 
   telephone numbers when they change service provider, move to a new 
   location, or change the subscribed services [14].  In many counties, 
   such as the United States and Canada, the functions of naming and 
   addressing on the PSTN have been abstracted.  The dialed directory 
 
 
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   number is not routable on the PSTN and must be translated into a 
   routing number for call completion. 
    
   The following Enumservice is registered with this document: "npd" to 
   indicate number portability data.  The purpose of this Enumservice is 
   to describe information about telephone numbers which cannot be used 
   on the public Internet or a private/peered Internet Protocol (IP) 
   network.  Thus, these are numbers which are only reachable via the 
   traditional Public Switched Telephone Network (PSTN). 
    
   This Enumservice could enable carriers, as well as other service 
   providers and users, to place ported, pooled, and blocks of numbers 
   and their associated PSTN contact information, into ENUM databases, 
   using standardized, non-proprietary methods.  This, in turn, could 
   enable such parties to consolidate all telephone number lookups in 
   their networks into a single ENUM lookup, thereby simplifying call 
   routing and network operations, which would then result in either an 
   on-net, or IP-based response, or off-net, or PSTN-based response.  It 
   is conceivable that being able to query for this information in ENUM 
   could significantly reduce or eliminate the need for these parties to 
   maintain traditional, SS7/TCAP/SIGTRAN-based query gateways, 
   applications, and protocols in their networks. 
    
   The service parameters defined in RFC 3761 dictate that a "type" and 
   a "subtype" should be specified.  Within this set of specifications 
   the convention is assumed that the "type" (being the more generic 
   term) defines the service and the "subtype" defines the URI scheme. 
    
   When only one URI scheme is associated with a given service, it 
   should be assumed that an additional URI scheme to be used with this 
   service may be added at a later time.  Thus, the subtype is needed to 
   identify the specific Enumservice intended. 
    
   In this document, there is one URI scheme specified, 'tel:', as 
   specified in RFC 3966 [9], and as further specified with number 
   portability data in draft-ietf-iptel-tel-np-06.txt [10] (Internet-
   Draft New Parameters for the "tel" URI to Support Number Portability, 
   draft-ietf-iptel-tel-np-06.txt [10]). 
    
3. ENUM Service Registration for NPD 
    
   Enumservice Name: "npd" 
    
   Enumservice Type: "npd" 
    
   Enumservice Subtype: "tel" 
    
   URI Scheme: 'tel:' 
    
 
 
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   Functional Specification: 
    
   This Enumservice indicates that the remote resource identified can be 
   addressed by the associated URI scheme in order to initiate a 
   telecommunication session, which may include two-way voice or other 
   communications, to the PSTN. 
    
   Security Considerations: See Section 5. 
    
   Intended Usage: COMMON 
    
   Authors: 
    
   Jason Livingood and Richard Shockey (for author contact detail see 
   Authors' Addresses section) 
    
   Any other information the author deems interesting: 
    
   None 
    
4. Examples 
 
   The following sub-sections document several examples for illustrative 
   purposes.  These examples shall in no way limit the various forms 
   that this Enumservice may take. 
    
4.1 Example of a Ported Telephone Number 
    
   $ORIGIN 3.1.8.7.1.8.9.5.1.2.1.e164.arpa. 
   NAPTR 10 100 "u" "E2U+npd:tel" 
   "!^.*$!tel:+1-215-981-7813;rn=+1-215-981-7600;npdi!" 
    
   In this example, a Routing Number (rn) and a Number Portability Dip 
   Indicator (npdi) are used as shown in draft-ietf-iptel-tel-np-06.txt 
   [10] (Internet-Draft New Parameters for the "tel" URI to Support 
   Number Portability, draft-ietf-iptel-tel-np-06.txt [10]).  The ænpdiÆ 
   field is included in order to prevent subsequent lookups in legacy-
   style PSTN databases. 
    
4.2 Example of a Non-Ported Telephone Number 
    
   $ORIGIN 3.1.8.7.1.8.9.5.1.2.1.e164.arpa. 
   NAPTR 10 100 "u" "E2U+npd:tel" 
   "!^.*$!tel:+1-215-981-7813;npdi!" 
    
   In this example, a Number Portability Dip Indicator (npdi) is used 
   [10].  The ænpdiÆ field is included in order to prevent subsequent 
   lookups in legacy-style PSTN databases. 
    
 
 
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5. Security Considerations 
    
   DNS, as used by ENUM, is a global, distributed database.  Thus any 
   information stored there is visible to anyone anonymously.  While 
   this is not qualitatively different from publication in a Telephone 
   Directory, it does open or ease access to such data without any 
   indication that such data has been accessed or by whom it has been 
   accessed. 
    
   Such data harvesting by third parties is often used to generate lists 
   of targets for unsolicited information.  Thus, a third party could 
   use this to generate a list that they can use to make unsolicited 
   "telemarketing" phone calls.  Many countries have do-not-call 
   registries or other legal or regulatory mechanisms in place to deal 
   with such abuses.   
    
   Carriers, service providers, and other users may simply choose not to 
   publish such information in the public E164.ARPA tree, but may 
   instead simply publish this in their internal ENUM routing database 
   which is only able to be queried by trusted elements of their 
   network, such as softswitches and SIP proxy servers. 
    
   Although an E.164 telephone number does not appear to reveal as much 
   identity information about a user as a name in the format 
   username@hostname (e.g., an email or SIP address), the information is 
   still publicly available, thus there is still the risk of unwanted 
   communication. 
    
   An analysis of threats specific to the dependence of ENUM on the DNS 
   and the applicability of DNSSEC [12] to this is provided in RFC 3761 
   [1].  A thorough analysis of threats to the DNS itself is covered in 
   RFC 3833 [13]. 
    
   DNS does not make any policy decisions about the records that it 
   shares with an inquirer.  All DNS records must be assumed to be 
   available to all inquirers at all times.  The information provided 
   within an ENUM NAPTR resource record must therefore be considered to 
   be open to the public, unless otherwise secured through split-DNS or 
   some other method, which is a cause for some privacy considerations. 
    
6. IANA Considerations 
    
   This document registers the 'npd' Enumservice and the subtype ôtelö 
   under the Enumservice registry described in the IANA considerations 
   in RFC 3761.  Details of this registration are provided in sections 3 
   and 4 of this document. 
    
7. Acknowledgements 
    
 
 
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   The authors wish to thank Tom Creighton, Jason Gaedtke, Jaime 
   Jimenez, and Chris Kennedy from Comcast Cable, Jonathan Rosenberg 
   from Cisco, and James Yu from NeuStar, for their helpful discussion 
   on this topic. 
    
8. References 
    
8.1 Normative References 
    
   [1] Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource 
   Identifiers (URI) Dynamic Delegation Discovery System (DDDS) 
   Application (ENUM)", RFC 3761, April 2004. 
    
   [2] ITU-T, "The International Public Telecommunication Number Plan", 
   Recommendation E.164, May 1997. 
    
   [3] Mockapetris, P., "DOMAIN NAMES - CONCEPTS AND FACILITIES", RFC 
   1034, November 1987. 
    
   [4] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part 
   Three: The Domain Name System (DNS) Database", RFC 3403, October 
   2002. 
    
   [5] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part 
   One: The Comprehensive DDDS", RFC 3401, October 2002. 
    
   [6] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part 
   Two: The Algorithm", RFC 3402, October 2002. 
    
   [7] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part 
   Four: The Uniform Resource Identifiers (URI)", RFC 3404, October 
   2002. 
    
   [8] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part 
   Five: URI.ARPA Assignment Procedures", RFC 3405, October 2002. 
    
   [9] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966, 
   December 2004. 
    
   [10] Yu, J., "New Parameters for the "tel" URI to Support Number 
   Portability", draft-ietf-iptel-tel-np-06.txt, June 2005. 
    
    
8.2 Informative References 
    
   [11] Bradner, et al., "IANA Registration for Enumservices email, fax, 
   mms, ems and sms", draft-ietf-enum-msg-05.txt, May 2005. 
    

 
 
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   [12] Arends, R. and et al., "Protocol Modifications for the DNS 
   Security Extensions", RFC 4035, March 2005. 
    
   [13] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name 
   System (DNS)", RFC 3833, August 2004. 
    
   [14] M. Foster, T. McGarry and J. Yu, "Number Portability in the 
   GSTN: An Overview", RFC 3482, February 2003. 
    
AuthorsÆ Addresses 
    
   Jason Livingood 
   Comcast Cable Communications 
   1500 Market Street 
   Philadelphia, PA 19102 
   USA 
    
   Phone: +1-215-981-7813 
   Email: jason_livingood@cable.comcast.com 
    
    
   Richard Shockey 
   NeuStar 
   46000 Center Oak Plaza 
   Sterling, VA 20166 
   USA 
    
   Phone: +1-571-434-5651 
   Email: richard.shockey@neustar.biz 
    
     
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