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Use of ENUM. Steven D. Lind AT&T 18 December 2000. ENUM From IP Perspective. Front End for Client Applications to Lookup Appropriate URI mailto:+19732366787 Interworking from IP-based Terminal to PSTN Phone
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Use of ENUM Steven D. LindAT&T18 December 2000
ENUM From IP Perspective • Front End for Client Applications to Lookup Appropriate URI • mailto:+19732366787 • Interworking from IP-based Terminal to PSTN Phone • Flexible Communication Client to Determine Best Method of Reaching Desired Destination
ENUM from PSTN Perspective • Allow Interworking with IP-based Networks • PSTN Users Can Dial Destinations on IP-based Networks without inventing new IP-address based dialing scheme • IP Users Can Reach PSTN Users through transparent dialing methods
PSTN PSTN Switch PSTN Switch Gateway Gateway IP Network LS DNS SIP Client SIP Client
+1-301-555-1234 2.PSTN Service Provider forwards toappropriate gateway Gateway(contains ENUM functionality) 3. Gateway formats URL (7.8.7.6.6.3.2.1.0.3.1.e164.arpa) and looks up name in dns 5. Gateway looks up A record of host for sip:jennyjones@sipservice.foo PSTN 1. Customer dials E.164 Number: 236-6787 7. Call gets routed to designated IP address. IP Network +1-301-236-6787 SIP Client 8. SIP Server routes call tospecified user. SIP Server PSTN Components 4. DNS returns NAPTR record(s) with: jennyjones@sipservice.foo 6. DNS returns IP Address of SIP Server for specified host DNS IP-based Network Components Voice Path Signaling Path
PSTN Components IP-based Network Components Voice Path Signaling Path +1-301-236-6787 SIP Client SIP Server 6. Location Server returns IP address of appropriate gateway (TRIP) IP Network 1. Customer dials E.164 Number: 1-301-555-1234 2. SIP Client formats URL (4.3.2.1.5.5.5.1.0.3.1.e164.arpa) and looks up name in dns 4. SIP Client initiates INVITEto SIP Server using “tel:” URL LS DNS 5. SIP Server looks up Gateway address from Location Server 7. Call gets routed to designated Gateway IP address 3. DNS returns service record telephone number(s) for end user as URI, e.g., tel:+13015551234 +1-301-555-1234 Gateway PSTN 8. Gateway completes callto PSTN