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VoIP, Portability, and the Evolution of Addressing

VoIP, Portability, and the Evolution of Addressing



LNPA & Future of Numbering Working Groups

LNPA & Future of Numbering Working Groups



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  • Number must be in full E.164 format including Country Code

VoIP, Portability, and the Evolution of Addressing VoIP, Portability, and the Evolution of Addressing Presentation Transcript

  • VoIP, Portability, and the Evolution of Addressing LNPA & Future of Numbering Working Groups April 14, 2005 Presented by Penn Pfautz
    • In a pre-LNP environment, call routing based on 6-digit (NPA-NXX) translation of destination number from LERG.
    • In an LNP environment, call routing based on 6-digit (NPA-NXX) translation of a Location Routing Number (LRN).
    PSTN Routing Regional NPAC SMS Carrier LSMS LNP SCP Porting Carrier Switch NPA-NXX Routing tables Dialed Number LRN Telcordia LERG™ industry broadcast record update Carrier OSS NPA-NXX CLLI Assoc. Trunk Selection Trunking data
  • Problem Statement & Solution Path
    • As carrier networks evolve to IP how should routing (including portability) be handled?
      • SIP is signaling protocol of choice; URIs which can be resolved to IP addresses are the elements of address specification
      • Unification of routing functions for all numbers (including portability) should be the objective so as to minimize service provider costs
    • Evolution of voice networks to IP and IP interconnection argues for an IP-based solution – e.g. some form of ENUM which was specifically designed to map E.164 numbers into URIs
      • Current ATIS PTSC NI-NI document envisions ENUM as target
      • Supports evolution away from code-based routing and associated limitations on numbering resource optimization
  • What is ENUM?
    • Provides mapping from E.164 numbers to IP resources
      • Defined by IETF in RFC 3761
      • Telephone number as domain name
      • Built on top of DNS
      • Look up returns URI
      • Example: +1-973-236-6797
    DNS Lookup sip:sfisher@att.net sip: sfisher@verizon.com mailto:sfisher1@att.com mailto:steve_fisher@yahoo.com
  • The Public ENUM Infrastructure $ORIGIN e164.arpa. IN NS nsnanp.enum.com . 4.4 IN NS sweden_enum.com . … $ORIGIN IN NS e164.att.net . IN NS e164.xyz.com . … $ORIGIN IN NAPTR 100 10 "u" "E2U+SIP" "!^.*$!sip:19732366797@att.net!" . e164.arpa Tier 0 (Country Code Registry) Tier 1 (Telephone Number Registry) Tier 2 (Application Information) International Implementation worked in IETF and ITU-T National Implementation worked in CC1 ENUM LLC and ENUM Forum (US) … nsnanp.enum.com ( e164.att.net sweden_enum.com (4.4.e164.arpa)
  • ENUM Call Flow Internet 794-867-5309 sip:7948675309@carrierc.net mms:7948675309@carrierc.net DNS MSC Carrier C MMSC Carrier A
  • Why ENUM?
    • Built on fundamental IP technology – not legacy foundation
      • Queries for URIs will come from IP network elements
      • No plans exist to update existing NP architecture (e.g. TRQ1-3) to make use of URIs
    • Distributed database, not SMS download
    • ENUM operates at a 10-digit level obviating the need for a separate portability correction
    • ENUM can support both end user and carrier provision of IP routing info
      • Many VoIP providers do not directly obtain numbering resources and so, not being code or block holders, cannot provision the NPAC or LERG
      • These are the carriers most likely to desire VoIP interconnection so their exclusion significantly limits scope of solution
        • FCC SBCIS decision could alter this but may not given the uncertainties surrounding its implementation (terms & costs of interconnection; qualification for the ESP exemption
    • ENUM can support both carrier specific interconnection and general “Internet” interconnection
  • ENUM Status
    • Country Code 1 ENUM LLC planning RFP for Tier 1 Registry operator to be in service mid 2006
    • Country Code 1 ENUM LLC members include AT&T, GoDaddy.com, MCI, SBC Laboratories, Sprint, Verizon, and BellSouth
    • ENUM in a domain other than e164.arpa can be rapidly implemented by a group of carriers should the public ENUM effort encounter difficulties
    • Some wireless carriers use private ENUM for message center identification today.
    • Other private ENUM implementations also exist
  • Alternatives to ENUM
    • As long as code-based routing remains, more efficient to tie specification of IP Point-of-Interface to CO code or switch CLLI and let LNP function normally to identify CO Code to be used in routing
    • This could be done as enhancement of LERG or via other processes