VoIP and ENUM Short Introduction AK-TK Workshop ÖFEG, March 11th, 2004 Richard STASTNY ÖFEG, Postbox 147, 1103-Vienna tel:

Richard Stastny 2  Some basic definitions  The pieces  Naming and addressing on the Internet, URIs  The Domain Name System (DNS)  VoIP and SIP  DDDS and ENUM  Putting all pieces together  ENUM History  Administration of ENUM Content

Richard Stastny 3  (User) Identification (and authentication)  identification of the user to the service provider (registration)  userID/PW, IMSI, …  always provider specific, not portable  Address  current network access point of the user terminal device  e.g. IP address, …  network specific, not portable  Name  mapped (dynamically) to the current address of the terminal, where the user has registered himself  mostly service related, sometimes portable  Terminology not consistent:  address, address-of-record are names What is required to establish a communication?

Richard Stastny 4  always numeric (with some exceptions)  used as identifiers, addresses and names  started as addresses and identifiers  now with number portability and service numbers also used as names  Types of phone numbers  private, local, national, international  E.164 numbers or International Public Telephone Numbers  Structure of E.164 numbering plan  CC N(S)N e.g. CC NDC SN  max 15 digits including 1-3 digit CC  no prefixes or access codes -> part of dialing plans What is a phone number?

Richard Stastny 5  Addresses: IPv4 and IPv6  Names: Uniform Resource Identifier (URIs)  alphanumeric character strings that identify abstract or physical resources on the Internet (RFC2396)  different formats, need to be defined in an RFC and registered with IANA  Examples:      tel:  URI's may contain IP addresses or domain names  Domain names need to be resolved with the Domain Name System (DNS) Naming and addressing on the Internet

Richard Stastny 6  The DNS is a distributed lookup system arranged hierarchically  It consists of 4 components  the name space  the name servers making that name space available  the resolvers (clients) querying that name space  a protocol  Domains, zones and delegation  a domain is a set of host names consisting of a single domain and all the domain names below it  a zone is any domain name delegated by an ancestor zone, ie a point of delegation  it contains all descendant domain names not been delegated  delegation means that somebody else is responsible for the subdomain  Resource Record (RR) is a unit of data  it defines some attribute for the domain  eg. an IP address, a mail route, a VoIP signaling route, a delegation  What the DNS is doing: I have "x", give me "y" Domain Name System (DNS)

Richard Stastny 7 Name Space und Name Server „root“ com orginfo biz net de int gov mil edu atseuk Top Level Domains stastnymicrosoftcooefeg atc Second Level Domains gTLDsccTLDs oefeg.co.at. xxx.stastny.com point of delegation Label

Richard Stastny 8 SIP “Trapezoid” Outbound Proxy Server User Agent B Inbound Proxy Server User Agent A SIP Media (RTP) DNS Server DNS Location Server SIP REGISTER INVITE DNS QUERY SRV iptel.org details next slide

Richard Stastny 9 Basic SIP Call-Flow (Proxy Mode) Location Database Proxy INVITE From: To: sip: Call-ID: #4 DNS SRV Query ? iptel.org #0 Reply: IP Address of iptel.org SIP Server INVITE From: To: sip: Call-ID: #1 #3 jiri #2 OK 200 From: To: sip: Call-ID: #5 OK 200 From: To: sip: Call-ID: #6 ACK #7 Media streams #8

Richard Stastny 10  The Dynamic Delegation Discovery System (DDDS) is a generic system to implement a binding of strings to data stored in a database and is defined in RFCs  The generic algorithm is defined in RFC3402  RFC3403 defines the usage of DNS as database and therefore also defines the DNS Resource Record to be used:  Naming Authority Pointer or NAPTR  it also defines the fields of a NAPTR and how to process a NAPTR  ENUM is a DDDS application  RFC2916bis defines therefore  the algorithm: how to map a E.164 number to a domain name  the service_field = "E2U" 1*(servicespec)  how to register servicespecs with IANA (template) ENUM and DDDS

Richard Stastny 11 ENUM in a nutshell  take phone number  turn it into a FQDN e164.arpa.  returns list of URI’s  ask the DNS for NAPTR

Richard Stastny 12 How does ENUM work ? Telephone Number (TN): translates to: e164.arpa set up call Tier 1 resolution to NS of authority ( pointer only) Tier 2 resolution to NAPTR record and SIP URL controlled at the end office e164.arpa. IN NS ns1.iphone.at IN NAPTR "u" “E2U+sip“

Richard Stastny 13 So what is ENUM adding? ENUM DNS SIP server SIP server session IN NAPTR e164.arpa. ?... NAPTR... DNS SRV lookup fwd.pulver.com

Richard Stastny 14 Bridging Internet & PSTN with ENUM ENUM DNS Media Gateway InternetzPSTN

Richard Stastny 15 Options for Corporate Users ENUM TDM PBX GW GK Internet * GK oder SIP Server GW 32

Richard Stastny 16 So how can ENUM be used? 1.Business: with IP PBX or IP Centrex  with geographic and/or numbers for networks (opt-in)  linking IP islands together globally via the Internet 2.Residential: with my geographic number (opt-in)  either as secondary line or as primary line (ported out) 3.Residential: with my mobile number  terminate IP originated calls on IP, plus evenually forwarding or forking to my mobile  operators may provide forced ENUM access from the PSTN 4.Residential and Business: ENUM-only number  IP device can be reached from PSTN and IP  calls may be dumped to IP in the originating network

Richard Stastny 17  ENUM is tightly linked with numbering and therefore with the regulatory framework  Deployment of ENUM is also tightly linked with the deployment of VoIP  Deployment of VoIP causes a direct conflict between Telco's and ISP's  Deployment of ENUM involves NRA's and Registries (in Europe primarily the ccTLD's)  ENUM and VoIP therefore cause a lot of questions and issues to surface. ENUM and VoIP as a Trigger

Richard Stastny 18  Sept – IETF ENUM WG – RFC2916  2001 – Various Workshops (ITU-T, Europe, US, …)  2002 – ITU-T Interim Procedures (IAB, RIPE-NCC) – ETSI SPAN11 TS "ENUM Administration in Europe" – Austrian ENUM Trial in operation (Sept. 2002)  2003 – ETSI SPAN11 TS "Minimum Requirements for Interoperability of European ENUM Trials" – IETF RFC2916bis WGLC – Various national and international ENUM Trials – using different scenarios and numbering resources – and using different ENUM-enabled products  2004 – ETSI ENUM Plugtests and Workshop – ENUM ready for production A (very short) ENUM History

Richard Stastny 19 Name Space +.arpa root comorginfonetdeint gov mil edu atseuk stastnymicrosoft cooefeg atc gTLDsccTLDs oefeg.co.at xxx.stastny.com arpa in-addre e164.arpa Tier 0 Tier 1 Tier 2

Richard Stastny 20 The ENUM "Tiers" Tier-0 Tier-1 Tier-2 Tier-1 Directs the DNS query to the customer’s Tier-2 providers. An NS* record is provided for each subscriber’s telephone number * An NS record is an authoritative Name Server DNS record used to delegate to subordinates Stores a list of service specific internet addresses in the form of URI’s in a DNS resource record called NAPTR for each subscriber. Returns the full list of Internet addresses associated with the E.164 number being queried. Registry RegistryRegistry Provider International-RIPE-NCC and ITU-TSB National CC 43 CC 1

Richard Stastny 21 ENUM Delegations  31Netherlands  33France  358Finland  36Hungary  374 Armenia  40Romania  41 Switzerland  420Czech Republic  421 Slovakia  423Liechtenstein  43Austria  44UK  46Sweden  48Poland  49Germany  55Brazil  86China  246Diego Garcia  247Ascension  290Saint Helena  971UAE  Antarctica Mobile  VISIONng UPT Delegations in e164.arpa as of 11. March 2003 additional Asian countries (Korea, Japan, …) soon to come

Richard Stastny 22 The End Thank you for your attention Contact (not Content) is King Douglas Rushkoff