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  1. 1. ENUM Advantages and Disadvantages VoIP World Congress 2006 Vienna, November 14th, 2006 Richard Stastny, ÖFEG* * The opinions expressed here may or may not be that of my company
  2. 2. Is ENUM Going a Full Circle? User ENUM Private ENUM Infrastructure ENUM Infrastructure ENUM User ENUM Private ENUM Private ENUM Private ENUM Private ENUM
  3. 3. <ul><li>Electronic or E.164 NUMber mapping is defined by the Internet Engineering Task Force (IETF) in RFC3761 as: </li></ul><ul><li>the mapping of „Telephone Numbers“ to Uniform Resource Identifiers (URIs) using the Domain Name System (DNS) in the domain e164.arpa </li></ul><ul><ul><li>URIs are used to identify resources on the Internet (e.g. http:// enum.nic.at ) </li></ul></ul><ul><li>The purpose of ENUM is to enable the convergence between the PSTN and the Internet </li></ul>ENUM is defined by the IETF
  4. 4. ENUM in a nutshell <ul><li>take an E.164 phone number </li></ul>+43 720 203 211 <ul><li>turn it into a FQDN </li></ul> <ul><li>returns list of URIs </li></ul>sip:richard@iphone.at <ul><li>query the DNS (for NAPTR) </li></ul>mailto:richard.stastny@oefeg.at sms tel:+436644204100 IN NAPTR 100 100 &quot;u&quot; “E2U+sip“ !^.*$!SIP:richard@iphone.at! .
  5. 5. The basic idea of ENUM (RFC3671) <ul><li>The basic idea of ENUM was </li></ul><ul><ul><li>to allow end-users </li></ul></ul><ul><ul><li>to opt-in with their EXISTING phone-numbers on the PSTN </li></ul></ul><ul><ul><li>into e164.arpa </li></ul></ul><ul><ul><li>to provide OTHER end-users with the capability </li></ul></ul><ul><ul><li>to look up contact URIs on the Internet the above end-user wants to link to this number </li></ul></ul><ul><li>This kind of ENUM is called User ENUM </li></ul>
  6. 6. ENUM Implementations <ul><li>30 Greece </li></ul><ul><li>31 Netherlands </li></ul><ul><li>33 France Trial closed </li></ul><ul><li>350 Gibraltar </li></ul><ul><li>353 Ireland Trial </li></ul><ul><li>354 Iceland </li></ul><ul><li>358 Finland </li></ul><ul><li>359 Bulgaria </li></ul><ul><li>36 Hungary </li></ul><ul><li>374 Armenia </li></ul><ul><li>386 Slovenia requested </li></ul><ul><li>39 Italy </li></ul><ul><li>40 Romania </li></ul><ul><li>41 Switzerland Trial </li></ul><ul><li>420 Czech Republic Trial </li></ul><ul><li>421 Slovakia Trial </li></ul><ul><li>423 Liechtenstein Trial </li></ul><ul><li>43 Austria </li></ul><ul><li>44 UK Trial </li></ul><ul><li>46 Sweden Trial </li></ul><ul><li>47 Norway </li></ul><ul><li>48 Poland </li></ul><ul><li>49 Germany </li></ul><ul><li>246 Diego Garcia </li></ul><ul><li>247 Ascension </li></ul><ul><li>262 Reunion (fr) </li></ul><ul><li>290 Saint Helena </li></ul><ul><li>508 St. Pierre and Miquelon (fr) </li></ul><ul><li>52 Mexico requested </li></ul><ul><li>55 Brazil </li></ul><ul><li>590 Guadeloupe (fr) </li></ul><ul><li>594 French Guiana </li></ul><ul><li>596 Martinique </li></ul><ul><li>61 Australia Trial </li></ul><ul><li>62 Indonesia requested </li></ul><ul><li>63 Philippines Trial </li></ul><ul><li>66 Thailand </li></ul><ul><li>65 Singapore Trial </li></ul><ul><li>81 Japan Trial </li></ul><ul><li>82 Korea Trial </li></ul><ul><li>84 Vietnam </li></ul><ul><li>86 China Trial </li></ul><ul><li>88234 Global Networks ? </li></ul><ul><li>87810 VISIONng UPT </li></ul><ul><li>971 UAE </li></ul>http:// www.ripe.net/enum/request -archives/ Delegations in e164.arpa as of Oct 24th, 2006 <ul><li>1 North America (US, CA, Jamaika) </li></ul><ul><li>additional Asian countries (Taiwan…) have trials, but not in .arpa </li></ul>
  7. 7. The draw-backs of the original approach <ul><li>Privacy concerns reduced the usability of ENUM basically to VoIP </li></ul><ul><li>Most VoIP providers do not provide end-users with SIP URIs to be reached on the Internet without termination fees </li></ul><ul><li>Why should an end-user pay for the benefit of other users? </li></ul><ul><li>How to overcome Metcalfe’s Law? </li></ul><ul><li>Nobody understands ENUM </li></ul>
  8. 8. But the real problem is: <ul><li>User ENUM requires </li></ul><ul><ul><li>country opt-in </li></ul></ul><ul><ul><li>end-user opt-in </li></ul></ul><ul><li>“ Service providers” have no say in User ENUM </li></ul><ul><li>So Service Providers using IP-based technology need other solutions to be able to Interconnect </li></ul><ul><ul><li>via IP-based technology and </li></ul></ul><ul><ul><li>using E.164 Numbers </li></ul></ul>
  9. 9. NGN/IP Interconnect (VoIP Peering) <ul><li>If we take the All-IP paradigm seriously, we have two basic requirements : </li></ul><ul><ul><li>Any real-time communication originating on IP and terminating on IP MUST stay on IP end-to-end </li></ul></ul><ul><ul><li>This implies, it MUST NOT use the PSTN/ISDN to interconnect. </li></ul></ul><ul><li>Benefits are: </li></ul><ul><ul><li>improved end-to-end functionality (BB codecs, IM, video, conferencing, presence, …) </li></ul></ul><ul><ul><li>Improved end-to-end QoS </li></ul></ul><ul><ul><li>No additional cost beside of IP-access </li></ul></ul><ul><ul><li>convergence possible at the end-user’s device </li></ul></ul>
  10. 10. Infrastructure ENUM – first try <ul><li>A tree for service providers is needed </li></ul><ul><li>ETSI created TR 102 055 „ENUM Scenarios for User and Infrastructure ENUM“ discussing the options and the problems: </li></ul><ul><ul><li>It should be a single global tree </li></ul></ul><ul><ul><li>Service provider opt-in </li></ul></ul><ul><ul><li>No regulatory involvement required </li></ul></ul><ul><li>But: </li></ul><ul><ul><li>Who is in charge? </li></ul></ul><ul><ul><li>Where to place the tree (public, private) </li></ul></ul><ul><ul><li>How to get ALL service providers to agree on this </li></ul></ul><ul><ul><li>etc., etc. </li></ul></ul>
  11. 11. Nevertheless, a solution was needed <ul><li>IP-based service providers wanted to peer (interconnect) their SIP traffic </li></ul><ul><ul><li>based on E.164 numbers </li></ul></ul><ul><li>So a number of VoIP peering federations including some kind of E.164 resolution where established: </li></ul><ul><li>XConnect, VPF, e164.info, SPIDER, … </li></ul><ul><li>Most of them based on ENUM technology </li></ul>
  12. 12. The ENUM Matrjoschkas
  13. 13. Private ENUMs <ul><li>Also called: </li></ul><ul><ul><li>Operator ENUM </li></ul></ul><ul><ul><li>Enterprise ENUM </li></ul></ul><ul><ul><li>Carrier ENUM </li></ul></ul><ul><li>This is currently how “service providers” interconnect: </li></ul><ul><li>Variants: </li></ul><ul><ul><li>Private ENUM in a “walled garden” extranet (GSMA) </li></ul></ul><ul><ul><li>SIP Exchange with restricted access on the Internet (Cable providers, XConnect, SIP-IX, …) </li></ul></ul><ul><ul><li>public tree not in „e164.arpa“ (e164.info) </li></ul></ul><ul><li>Advantages: </li></ul><ul><ul><li>No user opt-in, NO REGULATORS INVOLVED , intrinsic peering agreements, savings in CAPEX, OPEX, MM-services </li></ul></ul><ul><li>Disadvantages: </li></ul><ul><ul><li>limited reach, </li></ul></ul><ul><ul><li>no global solution, </li></ul></ul><ul><ul><li>how to peer with other federations? </li></ul></ul>
  14. 14. Infrastructure ENUM – second try <ul><li>All types of private ENUMs have serious d isadvantages: </li></ul><ul><ul><li>limited reach, </li></ul></ul><ul><ul><li>no global solution, </li></ul></ul><ul><ul><li>how to peer with other federations? </li></ul></ul><ul><li>Only numbers from providers participating in the given federation can be reached </li></ul><ul><li>To enable global reachability on IP, a single, common and global tree is required. </li></ul><ul><li>The first goal of Infrastructure ENUM is to create an anchor place where any E.164 number can be found and will: </li></ul><ul><ul><li>either be mapped directly to an ingress point of the destination network, </li></ul></ul><ul><ul><li>or at least hints can be found in which private E.164 resolution spaces the number can be resolved. </li></ul></ul>
  15. 15. Public Infrastructure ENUM <ul><li>If Infrastructure ENUM is intended to allow the mapping of any E.164 number </li></ul><ul><ul><li>that can be reached via IP </li></ul></ul><ul><ul><li>even if it terminates on the PSTN </li></ul></ul><ul><ul><li>to a SIP URI, </li></ul></ul><ul><li>Infrastructure ENUM must be in the public DNS. </li></ul><ul><li>But this is useless, if the resulting SIP URI cannot be reached </li></ul><ul><li>So for Infrastructure ENUM also a global IP Interconnect (VoIP Peering) regime is required. </li></ul><ul><li>ENUM is an applet to VoIP Peering </li></ul>
  16. 16. Standardisation in IETF <ul><li>Two recent major developments in IETF regarding (VoIP) Interconnect: </li></ul><ul><ul><li>ENUM WG extended scope to include Infrastructure ENUM </li></ul></ul><ul><ul><li>Voipeer BoFs to create new SPEERMINT WG: </li></ul></ul><ul><li>Session PEERing for Multimedia INTerconnect </li></ul><ul><ul><li>WG established 8. February 2006 </li></ul></ul>
  17. 17. Separation of Scope <ul><li>The ENUM WG is primarily concerned with the acquisition of Call Routing Data (CRD) e.g. a SIP URI, </li></ul><ul><li>while the SPEERMINT WG is focused on the use of such CRD. </li></ul><ul><li>Importantly, the CRD can be derived from ENUM (i.e., an E.164 DNS entry), or via any other mechanism available to the user. </li></ul>
  18. 18. Scope ENUM and SPEERMINT Infrastructure ENUM Policy Database ENUM Lookup Policy Lookup I-ENUM SPEERMINT Number SIP URI Routing Parameter
  19. 19. Current I-Ds in ENUM <ul><li>Infrastructure ENUM Requirements </li></ul><ul><li>The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application for Infrastructure ENUM </li></ul><ul><li>Combined User and Carrier ENUM in the e164.arpa tree (interim solution) </li></ul><ul><li>The ENUM Branch Location Record (interim solution) </li></ul><ul><li>IANA Registration for an Enumservice to Hint to E.164 Resolution Namespaces (ERN) </li></ul>
  20. 20. SPEERMINT Interconnect <ul><li>Interconnection procedures: </li></ul><ul><ul><li>(Eventually take output of ENUM) </li></ul></ul><ul><ul><li>Analysis of target URI </li></ul></ul><ul><ul><li>Check routing and peering policy (e.g. federation and NNI detection) </li></ul></ul><ul><ul><li>Discovery of next hop </li></ul></ul><ul><ul><li>Routing of SIP messages </li></ul></ul><ul><ul><li>Session establishment </li></ul></ul><ul><ul><li>Media transfer </li></ul></ul>
  21. 21. Types of Peering <ul><li>Direct peering </li></ul><ul><ul><li>the originating provider may identify and interconnect directly with the terminating provider </li></ul></ul><ul><li>Assisted peering </li></ul><ul><ul><li>involves the deployment of centralized SIP elements on the Internet or by a federation </li></ul></ul><ul><li>Indirect peering </li></ul><ul><ul><li>involves transit SIP elements for the routing of SIP messages and eventually also for media </li></ul></ul>
  22. 22. Finding the „Policies“ <ul><li>Location </li></ul><ul><ul><li>of the terminating provider </li></ul></ul><ul><li>Interoperability </li></ul><ul><ul><li>compatibility with terminating provider (identifying the NNI/UNI) </li></ul></ul><ul><li>Security </li></ul><ul><ul><li>of message transport (TLS, IPSec, VPN, ..) </li></ul></ul><ul><li>Trust </li></ul><ul><ul><li>authentication, privacy, identity, SPIT prevention, … </li></ul></ul><ul><li>Routing </li></ul><ul><ul><li>of messages to next hop </li></ul></ul><ul><li>Cost </li></ul><ul><ul><li>Fees, type of charges, … </li></ul></ul>
  23. 23. What are the Benefits of ENUM? <ul><li>ENUM is using the DNS </li></ul><ul><ul><li>it’s there, it works, it’s global, it scales, it’s reliable, it’s open, anyone can use it… </li></ul></ul><ul><ul><li>saving CAPEX </li></ul></ul><ul><li>Enables the originating administrative domain to do an All Call Query (ACQ) to find the destination network </li></ul><ul><ul><li>Ultimate solution in Number Portability </li></ul></ul><ul><li>Provisioning is done only by the destination (recipient) administrative domain for the E.164 numbers this domain is hosting </li></ul><ul><ul><li>saving OPEX </li></ul></ul><ul><li>Enables all multimedia (MM) services for E.164 numbers for all sessions on IP end-to-end </li></ul><ul><ul><li>enables convergence (whatever that means) </li></ul></ul>
  24. 24. What are the benefits of SPEERMINT? <ul><li>Enable interconnection in public and „private“ environments </li></ul><ul><li>Use the DNS also for policy functions </li></ul><ul><ul><li>saving CAPEX </li></ul></ul><ul><li>Provisioning done mainly by the destination administrative domain </li></ul><ul><ul><li>saving OPEX </li></ul></ul><ul><li>Enables multimedia (MM) services for any Public User Identifier for all sessions on IP end-to-end </li></ul>
  25. 25. Benefits in a nutshell <ul><li>The major benefits of Infrastructure ENUM and SPEERMINT for (VoIP) carriers and (VoIP) service providers is to save costs: </li></ul><ul><li>Minimal CAPEX for setting up the required infrastructure to provide the routing data </li></ul><ul><li>Minimal OPEX for maintaining routing data: </li></ul><ul><ul><li>Announce the E.164 numbers you host (in ENUM) </li></ul></ul><ul><ul><li>Announce the domains you host (in DNS) </li></ul></ul><ul><ul><li>(make bilateral or multilateral peering agreements) </li></ul></ul><ul><ul><li>Query ENUM and DNS to find any other destination provider </li></ul></ul>
  26. 26. What are the Open Issues? <ul><li>The Internet is based on end-to-end communication and best effort, no central intelligence </li></ul><ul><ul><li>this causes also a lot of problems (SPAM, DoS, spoofing, phishing, …) </li></ul></ul><ul><li>The PSTN has central control, QoS and a different business model, </li></ul><ul><ul><li>but it is a one trick pony </li></ul></ul><ul><li>The dream of the NGN </li></ul><ul><ul><li>take the benefits of the PSTN (especially the business model) and move it over to IP technology </li></ul></ul>The answer is money, what was the question?
  27. 27. Currently we have some options <ul><li>NGN, IMS? </li></ul><ul><ul><li>trying to rebuild the IN-silos on IP </li></ul></ul><ul><ul><li>keeping the central intelligence by adding service control </li></ul></ul><ul><ul><li>problems: contrary to the Internet Architecture </li></ul></ul><ul><ul><ul><li>getting to complex </li></ul></ul></ul><ul><ul><ul><li>loosing the innovation potential </li></ul></ul></ul><ul><li>Internet and P2P SIP? </li></ul><ul><ul><li>Back to: Keep it Simple, no administrative overhead, end-user control </li></ul></ul><ul><li>or – The Balkanization of the Internet? </li></ul>
  28. 28. What about User ENUM? <ul><li>User ENUM may finally co-exist with Infrastructure ENUM </li></ul><ul><li>Infrastructure ENUM will basically be used as a SS7 replacement for SIP- based services </li></ul><ul><li>User ENUM is an end-to-end Internet service usable for any kind of end user communication </li></ul><ul><li>End user will never host all their services with one provider </li></ul><ul><li>It may be used as an overlay for any type of services communities and enterprises. </li></ul>
  29. 29. From the IETF#67 last week in San Diego: <ul><li>Infrastructure ENUM: </li></ul><ul><ul><li>I-Ds in WGLC </li></ul></ul><ul><ul><li>No decision on ENUM root domain by IETF </li></ul></ul><ul><ul><li>RFCs will be forwarded to ITU-T </li></ul></ul><ul><ul><li>The ITU-T has to decide on the root </li></ul></ul><ul><li>Void draft revived: </li></ul><ul><ul><li>name changed to UNUSED for unallocated and unassigned numbers </li></ul></ul><ul><ul><li>URI changed to data: </li></ul></ul>
  30. 30. <ul><li>Thank you </li></ul>Richard Stastny ÖFEG +43 664 420 4100 [email_address] http://voipandenum.blogspot.com