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Why ENUM ?

ENUM --- A Mechanism for Personalized IP Services Management Using E.164 Number 周勝鄰 博士 工研院電通所 E-mail: slchou@itri.org.tw Tel: 03-5915616 2003. 07. Why ENUM ?. How do network elements (gateways, SIP servers etc) find services on the Internet if you only have a telephone (E.164) number?

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Why ENUM ?

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  1. ENUM --- A Mechanism forPersonalized IP Services ManagementUsing E.164 Number周勝鄰 博士工研院電通所E-mail: slchou@itri.org.twTel: 03-59156162003. 07

  2. Why ENUM ? • How do network elements (gateways, SIP servers etc) find services on the Internet if you only have a telephone (E.164) number? • How can subscribers define their preferences for incoming communications? • Many Number & Addressing Mechanism Used • With ENUM  Only One Number

  3. ENUM 101 • What is ENUM (RFC 2916)? • Make Telephone Number Become a Domain Name in Internet • Any Telephone Number can Register As Domain Name in IP World • Importance of ENUM • New Addressing Mechanism in IP World • Mechanism for IP/PSTN Convergence • Global ENUM Activities • IETF, ITU-T, US ENUM Form, Europe, … • ENUM Trials: More Than 10 Countries • Different Kinds of ENUM • Public (Personalized) ENUM: Future Vision • Carrier ENUM: Enhance MMS/SMS Services • Enterprise ENUM: Enhance Enterprise Telecomm Service

  4. What is ENUM ? Problem: How to Address (or Locate) a User in IP World from IP/PSTN Network ? ENUM is a Mechanism to Translate an E.164 Number into A List of URI (Service@Host) So that An IP User Can be Accessed by E.164 Number. ENUM Mechanism E.164 Number URI(Service@Host) Domain Name System (DNS)

  5. ENUM Domain

  6. Tier-0 Top Level Domain (TLD) • The Choice of Common Designated Domain fir ENUM Tier-0 is Undecided and is Proving Controversial • ARPA as ENUM TLD is Controlled by IETF and Operated by RIPE-NCC • US and some other countries, ISOC/IAB/IETF Support IETF Conclusion • European Union, France and Germany Proposed ITU-TSB as the Operator for ENUM • China, France, Germany, Syria and Spain Objected to ARPA as TLD for political reason  to reinforce the infrastructure of Internet governance • E.A-ENUM Recommendation • “Principle and procedures for the administration of E.164 Country codes for registration into the Domain Name System” • TLD is open • ITU-TSB is the ENUM Tier-0 Administrator

  7. ENUM in a Nutshell • take phone number +46-8-6859131 • turn into domain name 1.3.1.9.5.8.6.8.6.4.e164.arpa. • ask the DNS mailto:paf@cisco.com • return list of URI’s sip:paf@cisco.com Source: IETF

  8. DNS-Server Gateway Sip server ENUM in More Detail Query 1.3.1.9.5.8.6.8.6.4.e164.arpa.? Response sip:paf@cisco.com “Call setup” Dial +4686859131 Sip sip:paf@cisco.com Source: IETF

  9. .arpa ENUM DNS Hierarchy . Tier 0 (RIPE) 6.8.8.e164.arpa -> ns1.t1.com ns2.t1.com ns1.t1.com/ns2.t1.com 2.6.8.8.e164.arpa -> ns1.t1a.com; ns2.t1a.com 6.6.8.8.e164.arpa -> ns1.t1b.com; ns2.t1b.com Tier 1 ns1.t1a.com/ns2.t1a.com ns1.t1b.com/ns2.t1b.com ... ... 4.3.2.1.4.9.3.2.2.6.8.8.e164.arpa -> ns1.t2.biz; ns2.t2.biz 4.3.2.1.8.9.2.6.6.8.8.e164.arpa -> ns1.t2.org; ns2.t2.org ns1.t2.biz/ns2.t2.biz Tier 2 (Designated by the end user) 4.3.2.1.4.9.3.2.2.6.8.8.e164.arpa -> NAPTR RRs (ldap URL) Tier 3 (Depending on the application) ldap URL LDAP DB Source: James Yum, Neustar

  10. SIP Proxy ENUM Scenario Enum Record $ORIGIN 6.1.6.5.1.9.5.3.6.8.8.e164.arpa. IN NAPTR 100 10 “u” “sip+E2U” “!^.*$!sip:slchou@itri-sip-proxy.org.tw!” IN NAPTR 102 10 “u” “tel+E2U” “!^.*$!tel:+886910961527!” IN NAPTR 102 10 “u” “mailto+E2U” “!^.*$!mailto:slchou@itri.org.tw!” E-Mail Server DNS ENUM Server 3 SIP Phone 3 IP Network 5 2 Signal Gateway Media Gateway IAD • User Dial Tel. No • ENUM Query, get 3 URIs • Make SIP Call, No Answer • Make Mobile Call, Fail • Connect to E-Mail Softswitch 4 1 Dial:03-5915616 0910961527

  11. ENUM Scenario (cont.) • User Make Call to E.164 Number: 03-5915616 • Softswitch Translates the E.164 Number to Query Input to ENUM Server: • 6.1.6.5.1.9.5.3.6.8.8.e164.arpa and gets a list of URIs returned • The Softswitch Processes the 1st URI Record, • Query DNS to get the IP Address of Host: itri-sip-proxy.org.tw • Make SIP Call to SIP Phone of slchou through SIP Proxy • SIP Phone Does not Answer • The Softswitch Processes the 2nd URI Record, • Make PSTN Call Through Gateway to 0910961527 • 0910961527 Does not Answer • The Softswitch Processes the 3rd URI Record, • Query DNS to get the IP Address of Host: itri.org.tw • Connect the Caller E-Mail Server SMTP Protocol • Caller Leave the E-Mail Message

  12. Internet/ Data Network ENUM and MMS Service Step 3b ENUM Server Step 2 Query: 5.4.3.2.1.0.4.4.9.e164.apra Step 1 Step 3a To: 0944-012345 ‘SMS Based’ Gateway MMSC ‘B’ SGSN GGSN Response mms:0944012345@domainB Registry Server IP = 192.9.200.3 Network B MMS ‘A’ Network A

  13. ENUM Administrative Model

  14. Registry vs. Registrar • Registry • Runs the DNS server for a specific domain name • one domain -> one registry • Registrar • Provide ENUM Registration to ENUM Users • So that Users Need Not to Contact Registry • Registrar verify customer data, do billing, and send data to registry when delegation is to be done, changed or cancelled

  15. ITU-T ENUM Activities • ITU-T Study Group 2 • Interim Procedures for Use of the ARPA Domain • Approved in May, 2002 • Interim procedures for delegation of E.164 country codes into ARPA domain before Approval of E.A-NUM • RIPE-NCC is Authorized by ITU-TSB to Perform such Delegation at this Stage • http://www.ripe.net/enum/instructions.html

  16. IETF ENUM Activities • Telephone Number Mapping (ENUM) WG • RFC 2916, “E.164 number and DNS” • RFC 2915, “The naming authority pointer (NAPTR) DNS resource record”, August, 2000 • RIPE-NCC • Related ENUM Activities after RFC 2916 • Update RFC to reference the DDDS • RFC2916bis,”The E.164 to URI DDDS Application” • ENUM Administrative and Operational Prtocedures • Registration and Provisioning Procedures, Validation and Authentication of Data • Operational Privacy, Security Issues and Procedure • IETF Liaison with ITU-T SG2 • New Issues Being Considered: • Extent Same URI in RFC 2916 for Different Service • e.g., 2 SIP URIs but one for voice and one is instant messaging • SIP vs. ENUM Services, e.g., distinction the location provided by SIP and ENUM • Adding Presence as an ENUM service • Extension of ENUM service ‘tel’ URI • Location Number Portability, using DNS as the source • Extensible Provisioning Protocol (EPP) in PROVREG WG, IETF

  17. 886 Issue in IP World • Permanent Caching 6.8.8.e164.arpa pointing to Taiwan ENUM Tier-1 • in other Countries Tier-1 ENUM TLD 6.8.8.e164.arpa 6.8.8.e164.arpa US ENUM TIER 1 Taiwan ENUM TIER 1 JPN ENUM TIER 1 ENUM TIER 2 ENUM TIER 2 ENUM TIER 2 ENUM TIER 2 ENUM TIER 2

  18. ENUM Provisioning Issues • Privacy Issues • Need to obtain end-user agreement to enter number in DNS, depending on national data-protection laws • Hardening the ENUM zone data against data mining, especially for the purposes of spam? • But hard to stop ENUM name servers being harvested for resources bound to an E.164 number • Security Issue • Almost no security in normal DNS • Transaction Signatures (TSIG) provides simple form of DNS Security based on shared secret • Ultimately DNSSEC needs to be deployed • uses public key encryption to generate digital signatures for every resource record in a zone • public keys are also signed and included in the zone, allowing the signatures to be validated

  19. ENUM Provisioning Issues • Service Integrity • Unexpected Service Activated to the Caller • Service Provisioning and Management • E.164 Number Authentication • Service Validation on NAPTR Modifications ?

  20. More Than Number Translation • One E.164 Number to Multiple URIs • Multiple NAPTR  service: URI • Multiple IP Services Behind one ENUM • sip, tel, ifax, mms, ems, sip, e-mail, … • Service Realization Mechanism in IP World • Service Realization for ASP • Service Selection • Service Management for ENUM Users • Web-based Service Management for ENUM Users • Service Applied Dynamically

  21. Conclusions • ENUM is An Important Enabling Technology to Speed-up IP/PSTN Convergence • ENUM --- Let Users Use Telephone Number in IP Network • ENUM --- Make Users to Manage Different IP Services Uniformly • ENUM Will Bring Huge Impact to PSTN and IP Networks

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