1 ENUM’s Role in VoIP IP Telephony Conference & Expo Miami February 12, 2004 Sheri Jenkinson VeriSign Communication Services Product Manager - ENUM (913)

2 ENUM Overview  What does ENUM mean to the service provider?  How does it enhance the User experience?  What does a typical call flow look like?  Where does the industry stand on ENUM deployment?

3 What ENUM Means to VoIP Providers  An efficient method of interconnecting packet switched services with traditional circuit switched services.  A “light weight” means of formatting queries to enable query/response access to IN databases.  Less expensive IP infrastructure to access IN data (LRN, 800, CNAM, LIDB) using TCP/IP for traditional voice services.  ENUM is designed to work with the proven DNS infrastructure.  Enables Least Cost/Most Efficient Routing  Revenue $$$ - ENUM facilitates creation of enhanced services which use TNs and URL based addresses.

4 What ENUM Means to Subscribers and Users and of VoIP Services  Users only need one number to access multiple modes of communication (fax, unified messaging, , multiple phone numbers)  Easier to key phone numbers instead of longer addresses for sending text.  Subscribers can easily manage their personal contact information.  Availability of enhanced services.

5 User Directory for Multiple Registered Services A requesting computer can deliver information to several devices just by knowing a phone number. This could be a number from a business card. Now the user can send information to a business associate based on the options returned by the query. ENUM CLIENT Tier 2 Name Server Tier 1 Registry User enters the known 10 digit TN and receives the full NAPTR record to select a registered service and send the message.

6 Behind the Scenes Requestor Requestor types into their browser a E.164 number: The requestor’s software converts the phone number With country code into a ENUM ready number e164.arpa Tier 0 database will direct the request to the North American Tier I databases based on the country code of 1 and the NPA. The Tier II database will return to the requesting computer the list of service specific addresses (URIs) associated with the queried number e164.arpa Tier e164.arpa Tier I TN looked up & URI returned Tier II. The Root Node Tier I resolves the fully qualified 10 digit number. It then directs the DNS query to the customer’s Tier II provider. The NS record is provided for the subscriber’s telephone number. The root node is the root server that directs queries to.arpa for public ENUM.

7 ENUM ENABLES PSTN to SIP CALLS ENUM Server Media Gateway STP Signaling Gateway MGC SSP Proxy Server A Proxy Server B 1 SIP: User B ENUM e164.arpa 5 4 Invite 3 2 Invite 6 Invite 7 User A Invite: From: Invite: SIP: From: In this example, User A attempts to contact User B who is on a VoIP network and uses a SIP phone. 1.User A dials the global E.164 number for User B. 2.The SSP sends an IAM message via SS7 to a SG (which is part of the Media Gateway Controller / Media Gateway). 3.The Media Gateway Controller sends an invite message to the nearest Proxy Server. 4.Proxy Server A does not know User B address; therefore it contacts an ENUM Server. 5.The ENUM Server returns the address of User B. 6.Proxy A sends invite message to User B’s Proxy Server B 7.Proxy Server B passes the invite to User B 8.If User B accepts the call, there is a two-way RTP path established between User B and the Media Gateway controller. A two-way path is also established between the Media Gateway and User A. At this point User A is able to communicate with User B. 8 SCP LRN CNAM 800 LIDB Other

8 STATUS OF ENUM  The NTIA has seen an increased interest in ENUM from the industry.  The LLC is the NTIA and FCC preferred method for a contracting agency on ENUM.  Multiple Tier 1 approach for the US is favored due to the fact that it provides multiple business opportunities, business redundancy in case of a business failure, and technical reliability. –Getting the NANP members to agree on a single Tier 1 for the NANP or a Skinny Tier 1 would be timely and difficult at first glance. –Considering migrating to use of a Skinny Tier 1 for better control of NPA distribution within a country code.  Move the ENUM efforts forward at a steady pace with a possible ENUM deployment for the US at the end of the year or at least some form of trial.  Globally – Several countries have implemented ENUM trials that are to be reviewed at the ETSI Working Group Meeting at the end of February.

9 OPEN ISSUES  Non-Geographic Numbers have not been addressed. This is an issue for the ITU as well as for the ENUM Forum.  Toll Free - 800, 888, 880, 500, etc.  Other – 900, 456, 700  Multiple Tier I Entities for the US is favored by the NTIA and FCC  Selection process for Tier 1 providers and governing rules for LLC.  Administration of NPA distribution to the selected Tier 1 entities  Carrier interoperability – secure access to required network element mailto addresses.  Use of WhoIs and privacy concerns  VeriSign has developed an alternative for discovery and query of distributed ENUM registration data among ENUM registries (EREG) using IRIS.

10 Additional Links for ENUM Information  rfc2916bis-07.txt rfc2916bis-07.txt 

11 ACRONYMS A Record(A host Address) ARPA(Address and Routing Parameters Area) CNAME(Canonical Name Record) DNAME(DNS Non-Terminal Name Redirection) DNS(Domain Name Server) E.164(ITU telephone numbering plan) IETF(Internet Engineering Task Force) IRIS(Internet Registry Information Service) ITU(International Telecommunication Union) MGC(Media Gateway Controller) NAPTR(Naming Authority Pointer Record in a DNS) NS(Authoritative Name Server, DNS record) RTP(Real-Time Transport Protocol) SG(Signaling Gateway) SGA(Study Group A of the International Telecommunication Advisory Committee, US policy and regulatory aspects telecommunications services.) SIP(Session Initiation Protocol) URI(Uniform Resource Identifiers)