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Presentation to RIPE EOF. TIPHON Perspective on VoIP Numbering. John Horrocks (DTI) Tiphon WG4 Chair. Contents. Some basics Current work areas (SIP, ENUM, PINT, Tiphon) Tiphon issues Tiphon architecture and solution Future issues. Basics-1: Names and Addresses.
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Presentation to RIPE EOF TIPHON Perspective on VoIP Numbering John Horrocks (DTI) Tiphon WG4 Chair
Contents • Some basics • Current work areas (SIP, ENUM, PINT, Tiphon) • Tiphon issues • Tiphon architecture and solution • Future issues
Basics-1: Names and Addresses • Name: Unique identifier of communicating entity, used by network, may be structured for user and contain geographic information • Address: Location of entity in terms of network structure, therefore suitable for routing packets
Basics-2: Names and Addresses Acknowledgement: DGTP Netherlands
Where is .ovum.co.uk? Where is .co.uk? Where is .uk? IP address of server for .ovum.co.uk IP address of server for .co.uk IP address of server for .uk Basics - 3: DNS Resolution Stored IP address Root server One of 13 Calling host TLD server for .uk Time SLD server for .co.uk
Contents • Some basics • Current work areas (SIP, ENUM, PINT, Tiphon) • Tiphon issues • Tiphon architecture and solution • Future issues
Main current work areas • IETF: IPTEL general work based on SIP • ENUM selection of means to communicate with E.164 number, based on DNS, precursor to use of SIP for call • IETF: PINT Control connection between PSTN dial-up access and ISP • Tiphon: E.164 to IP resolution • ITU-T SG2: 14 issues Acknowledgement: DGTP Netherlands
IPTEL based on SIP Stage by stage set-up Proxy server Proxy server Location server Location server URL of next server SIP of called user Network Server Network Server URL of next UAS UAC UAS UAS UAC URL of current location of terminal Media packets sent to IP address of called UAS obtained from URL by DNS
ENUM Choosing the means of communication Query for 0.0.0.9.1.5.5.7.0.2.4.4.e164.int NAPTR records with services available Time Choice DNS Request SVR If needed SVR Now has domain name Start SIP procedure
PINT Internet PINTGateway IN Service Node Local Exchange Transit Exchange
Contents • Some basics • Current work areas (SIP, ENUM, PINT, Tiphon) • Tiphon issues • Tiphon architecture and solution • Future issues
Tiphon - The Problems • Choosing appropriate names (numbers) • Resolving names to IP addresses
Tiphon - Three Lessons 1 - Numbering relates to services not technology 2 - Regulation depends on services not technology (regulation for public telephony is already established) 3 - IP can support many different services Nonsense questions: - How do you number VoIP? - How do you regulate VoIP? Real question: What is the service? - Numbering and regulation follow
Tiphon Approach • Aiming primarily at needs of telcos/ISPs who provide telephony services over IP • Naming based on E.164 for public telephony (alternatives not excluded) • Expect telcos will want protected boundaries so design for step/step call set-up and media routing with migration to end-end • hacking • quality control • call related charging • culture (Can remove boundaries later) • Not dependent on public E.164-IP resolution system for starting
Where Tiphon fits in E.164 Why start from E.164? (Search engines) Choice ENUM Services Services Tiphon E.164 E.164 E.164 URL E.164 SIP IPTEL User@host Step-by-step Public resolution service not essential Public resolution service IP address Acknowledgement: DGTP Netherlands
Switched IP circuit networks networks Different service concepts Common service model Different service model ETSI Tiphon H.323 IETF SIP Voice telephony service SCN telephony IP telephony E.164 E.164 User@host + E.164 Interworking Switched IP circuit networks networks Acknowledgement: DGTP Netherlands
Public DNS based resolution systemCommon service numbering Needed for public E.164 - IP resolution service No updating from users or IP based operators without allocation from NRA Customers of IP operators allocated E.164 numbers under this system Acknowledgement: DGTP Netherlands
Contents • Some basics • Current work areas (SIP, ENUM, PINT, Tiphon) • Tiphon issues • Tiphon architecture and solution • Future issues
Service resolution (may be repeated) Service information could also be accessed by later gatekeepers Service information E.164 - IP routing resolution (may be repeated) E.164 - IP routing resolution (may be repeated) E.164 - IP local endpoint resolution (may be repeated) Search resolution E.164-IP Resolver E.164-IP Resolver E.164-IP Resolver Address book Search engine or Directory Called or Routing E.164 Called or Routing E.164 Called or Routing E.164 Next hop information Next hop information Terminal information E.164 number (directory number) Home Gatekeeper Any information on called party Gatekeeper Gatekeeper IP address for media Called E.164 Routing E.164 IP address for media H.225 signalling Media Calling terminal There are various options for this signalling Route on called E.164 Route on routing E.164 Tiphon: Incoming call Service information may be accessed either from SCN or IP If present SCN switch Ingress IP gateway Routing mostly uses tables in SCN switches. One switch may use IN for service information SCN technology IP technology
E.164 - IP Routing Resolution E.164 - IP Local Endpoint Resolution SC SC 1a - Cd R(E.164) or Cd (E.164) 4a - Cd R(E.164) 2a - S2i 5a - STi 6 - Set-up contains S2o may contain M2o 3 - Set-up contains S1o may contain M1o When 2a +2b received STi S2i Start CC CC CC Signalling 10 - Connect may contain MTi 12 - Connect may contain M2i S1o S2o 1b - Reserve media 4b - Reserve media 7 - Reserve media 8 - MTi Reserved 2b - M1o reserved 5b - M2i, M20 reserved 11 - Connect pairs (M2i,MTi), (M2o, M1o) 9 - Activate media 13 - Activate media M2o M1o BC BC BC MTi M2i 1b - Reserve media 4b - Reserve media 7 - Reserve media 5b - M2i, M2o reserved 2b - M1o reserved 8 - MTi Reserved 11 - Connect pairs (M2i,MTi), (M2o, M1o) 9 - Activate media 13 - Activate media M2i MTi MC MC MC Bearer M1o M2o Tiphon: Intermediate network Ingress Gateway Home Gateway Terminal Call set-up direction
SC SC 4a - Cd R(E.164) 2a - S2i 5a - S3i 1a - Cd R(E.164) 3 - Set-up contains S1o may contain M1o When 2a +2b received 6 - Set-up contains S2o, M2o S2i Start CC CC 9 - Connect may contain M2i S1o 7 - Connect S2o 1b - Reserve media 4b - Reserve media 2b - M1i, M1o reserved 5b - M2i, M20 reserved 8 - Connect pairs (M2i,M3i), (M2o, M1o) 10 - Connect pairs (M1i,M2i), (M1o, M0o) M1o BC BC M2i 1b - Reserve media 4b - Reserve media 5b - M2i, M2o reserved 2b - M1i, M1o reserved 10 - Connect pairs (M1i,M2i), (M1o, M0o) 8 - Connect pairs (M2i,M3i), (M2o, M1o) M2i MC MC M1o M2o Tiphon: Intermediate network M1i Network 1 Gateway Network 2 Gateway Call set-up direction
Contents • Some basics • Current work areas (SIP, ENUM, PINT, Tiphon) • Tiphon issues • Tiphon architecture and solution • Future issues
Multiple Users (different roles, different persons, distinctive alerting) Multiple terminals Multiple accesses (eg fixed, mobile 1, mobile 2) Multiple service providers Multiple services (eg telephony, fax data, video) The Future: Multi-Everything
Future solutions • Avoid a wholly new system allow smooth market-led migration • Grow E.164 for different roles/labels • Hide E.164 with better terminals and search engines • Work needed on privacy vs exchange of information to facilitate search engines
Tiphon welcomes you! • Next meeting: 13-17 March near Nice • All documents on web • Secretary: Laurent Vreck • +33 4 92 94 4373 www.etsi.org