18 January 2006 Copenhagen ERO - TISPAN WG4 meeting ENUM Doc 8_003 ENUM Ad-hoc Group "Carrier DNS" Proposal Kim Fullbrook, Chair ENUM Ad-hoc Group 18 January 2006 Copenhagen ERO - TISPAN WG4 meeting *Restricted – GSMA Members *Restricted – GSMA Associate Members Restricted Confidential - Information Access to and distribution of this document is restricted to the persons listed under the heading Security Classification Category*. This document is confidential to the Association and is subject to copyright protection. This document is to be used only for the purposes for which it has been supplied and information contained in it must not be disclosed or in any other way made available, in whole or in part, to persons other than those listed under Security Classification Category* without the prior written approval of the Association. The GSM MoU Association (“Association”) makes no representation, warranty or undertaking (express or implied) with respect to and does not accept any responsibility for, and hereby disclaims liability for the accuracy or completeness or timeliness of the information contained in this document. The information contained in this document may be subject to change without prior notice. © Copyright of the GSM Association 2004

Introduction ENUM resolves an E.164 number to a URI for specific services such as MMS or SIP/IMS DNS is the technology used to implement ENUM functionality “Infrastructure ENUM” is sometimes used to describe a DNS accessed only by telecomm carriers, not by end users The term “Carrier DNS” was created by the author because much more DNS information is required to be shared between telecomm carriers than just ENUM information.

Carrier DNS “Carrier DNS” carries information for use by telecomms companies relating to E.164 numbers and available services such as MMS, SIP/IMS etc. The DNS should be located on the same IP network which carries the (for example) MMS or SIP/IMS traffic DNS structure and ENUM details impact all operators globally, not just GSM operators ENUM proposals and DNS Principles & structure need to be discussed and agreed with non-GSM operators

ENUM Data Visibility Background: “Public ENUM” has been accepted in most countries to be “opt in” i.e. data is only added to the ENUM database for a particular E.164 number if the end user of this number agrees to put their data in it. Carrier ENUM cannot work like Public ENUM: All E.164 numbers must be added, otherwise you cannot route calls and other services (e.g. MMS messages) to every number This applies to services between countries (international calls) as well as within a country. A country’s Carrier DNS information must be visible to other carriers in every country globally, otherwise international calls into that country will fail

Hierarchy for "Carrier DNS" DNS is a hierarchical structure, like a large tree One Master Root (Tier 0) Master Root Server (Tier 0) Multiple Slave Roots (Tier 0) per network Slave Root Server (Tier 0) Slave Root Server (Tier 0) Slave Root Server (Tier 0) (Tier 1) Master & Slaves typically per country DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) (Tier 2) Master & Slaves typically per operator or centralised and shared DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2)

Multiple DNS Trees (also known as multiple root and “no root”) If there are multiple DNS trees existing for Carrier DNS, the querying becomes complex because you might have to make a query to each of these different DNS trees. The proposed solution involves one tree only: “Lookup the query in the Carrier DNS tree”. Multiple trees would significantly increase complexity: “Lookup the E.164 in Carrier DNS tree A operated by GSM carriers, then if it’s not there go to Carrier DNS tree B operated by Fixed carriers in Country X, and if it’s not there go to Carrier DNS tree C in the Internet. Then, if it’s not there go to the private DNS tree operated by Internet company Z etc…" Multiple trees would be difficult to maintain, increase call setup times and cause failed calls

Multiple DNS Hierarchies Where to find my E.164 number ??? ANO Master Root Server (Tier 0) IPX Master Root Server (Tier 0) A.N.O. Network Slave Root Server (Tier 0) Master Root Server (Tier 0) Slave Root Server (Tier 0) IPX Networks Public Internet DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) DNS Server (Tier 1) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) DNS (Tier 2) It is undesirable to have multiple DNS hierarchies because of the inefficiency and confusion caused

Where is Carrier DNS ? Potentially Carrier DNS could be on the Internet or a private Network For best efficiency and maintainability we want only one carrier DNS tree Do not want e.g. one in the GSM operators’ IPX network, one in CDMA operators’ CRX network, one in Fixed networks’ IP network plus one in the Internet etc. Many telecomms carriers have not made their views public DNS should be on the same network as the MMS & SIP/IMS etc traffic Potentially could use the enhanced GRX network (known as IPX) for a single Carrier DNS and transport for MMS, SIP/IMS etc

GRX and IPX GSM carriers already have access to the GRX networks (GPRS Roaming eXchange) The GRX network comprises multiple individual networks owned by various companies which are connected together at peering points effectively a private backbone for GSM operators Only GSM carriers can connect to the GRX today GRX is being enhanced to become the IPX

Proposed Solution for Carrier DNS Privacy and security concerns are addressed by: Putting Carrier DNS on a private controlled-access network Completely separate from the public Internet The controlled-access network is the IPX network (enhanced GRX) Telecomm information for every country globally that has launched these new services is added to the Carrier DNS Any organisation that wishes to connect to the IPX can do so provided that they adhere to the contractual terms of their chosen IPX provider There is competition between IPX providers

Proposed Solution (continued) The SIP/IMS calls, MMS messages etc run over the same IP network as the DNS traffic Other private telecomm networks (e.g. CDMA networks’ CRX) could be connected to the IPX An area for further study In those countries that require their telecomm information to be publicly available on the Internet: the telecomm information is made available in the Carrier DNS on both the Internet and the private network. Existing number portability arrangements can be integrated into the ENUM solution in "Carrier "DNS as desired Preferred design will vary by country

Summary “Carrier DNS” is needed for the next generation of telecomms services Data for all countries needs to be in this DNS The level of Security and Privacy concern for the Carrier DNS data will vary by country Security and Privacy concerns can be addressed by putting the DNS on the IPX network (enhanced GRX) Any organisation can connect to the IPX Carrier DNS can be built globally in the IPX with a single tree and one root In those countries where Carrier DNS data must be publicly accessible, carriers additionally place that data on the Internet in the e164.arpa domain

The End Any Questions ? (Optional supporting slides follow)