1January 2006Richard Stastny Developments around Infrastucture ENUM and their relevance on NGNs Workshop on NGN Interconnection and Numbering TRIS – TISPAN WG4 Copenhagen, 18. January 2006 Richard Stastny, ÖFEG* * The opinions expressed here may or may not be that of my company

January 2006Richard Stastny2 Content NGN/IP Interconnect – VoIP Peering –Some definitions What is ENUM? What kind of ENUM? –Infrastructure ENUM Recent IETF developments –ENUM WG –SPEERMINT WG Benefits in a nutshell

January 2006Richard Stastny3 Definitions What are NGNs? –IP-based “networks” –“Service provider” “networks” offering real-time or near realtime IP communications –“Enterprise networks” –etc. –  Administrative Domains What is Interconnection between NGNs? –a user registered in one administrative domain is able to contact (establish a session to) an user registered in a different administrative domain by using a Public User Identity (Address-of-Record, E.164 Number) –preferably via IP

January 2006Richard Stastny4 NGN/IP Interconnect (VoIP Peering) If we take the All-IP paradigm seriously, we have two basic requirements: –Any real-time communication originating on IP and terminating on IP MUST stay on IP end-to-end –This implies, it MUST NOT use the PSTN/ISDN to interconnect. Benefits are: –improved end-to-end functionality (BB codecs, IM, video, conferencing, presence, …) –Improved end-to-end QoS –No additional cost beside of IP-access –convergence possible at the end-user’s device

January 2006Richard Stastny5 Example IMS (TS ) Public User Identities –something one may put on a business card  a SIP URI or a TEL URI (in E.164 format) Routing* within IMS shall use SIP URIs –(converted via DNS to IP addresses – RFC3263) –TEL URIs will require conversion to SIP URIs (via ENUM)  Interconnection between IMS must be possible by using SIP URIs only * Routing = finding the next hop

January 2006Richard Stastny6 Possible Public User Identities E.164 numbers SIP URIs defined by provider: SIP URIs with self-provided domains:

January 2006Richard Stastny7 Electronic or E.164 NUMber mapping is defined by the Internet Engineering Task Force (IETF) in RFC3761 as: the mapping of „Telephone Numbers“ to Uniform Resource Identifiers (URIs) using the Domain Name System (DNS) in the domain e164.arpa –URIs are used to identify resources on the Internet (e.g. ) The purpose of ENUM is to enable the convergence between the PSTN and the Internet ENUM is defined by the IETF

January 2006Richard Stastny8 ENUM in a nutshell take an E.164 phone number turn it into a FQDN e164.arpa. returns list of URIs query the DNS (for NAPTR) sms tel: IN NAPTR "u" “E2U+sip“

January 2006Richard Stastny9 The basic idea of ENUM (RFC3671) The basic idea of ENUM was –to allow end-users –to opt-in with their EXISTING phone- numbers on the PSTN –into e164.arpa –to provide OTHER end-users with the capability –to look up contact URIs on the Internet the above end-user wants to link to this number This kind of ENUM is called User ENUM

January 2006Richard Stastny10 SIP Session establishment SIP server SIP server session DNS SRV lookup providerB.net IP –based network If this does not work, forget ENUM DNS

January 2006Richard Stastny11

January 2006Richard Stastny12 E.164 Session establishment SIP server SIP server tel: session DNS SRV lookup providerB.net DNS IN NAPTR e164.arpa. ?... NAPTR... What is ENUM adding? ENUM DNS

January 2006Richard Stastny13 What are the Benefits of ENUM? ENUM is using the DNS –it’s there, it works, it’s global, it scales, it’s reliable, it’s open, anyone can use it… –saving CAPEX Enables the originating administrative domain to do an All Call Query (ACQ) to find the destination network –Ultimate solution in Number Portability Provisioning is done only by the destination (recipient) administrative domain for the E.164 numbers this domain is hosting –Saving OPEX Enables all multimedia (MM) services for E.164 numbers for all sessions on IP end-to-end –Enables convergence (whatever that means)

January 2006Richard Stastny14 So what ENUM should be used? The ENUM Babuschka‘s

January 2006Richard Stastny15 The “ENUMs” User ENUM Private ENUM Operator ENUM Enterprise ENUM Federation ENUM Carrier ENUM Infrastructure ENUM EMINEM

January 2006Richard Stastny16 User ENUM User ENUM requires –country opt-in –end-user opt-in “Service providers” have no say in User ENUM So Service Providers using IP-based technology need other solutions to be able to Interconnect –via IP-based technology and –using E.164 Numbers

January 2006Richard Stastny17 Private ENUM Also called: –Operator ENUM –Enterprise ENUM An administrative domain is setting up their own private ENUM DNS –May be used in addition to other solutions to route within own network But does not solve the Interconnect problem with other administrative domains AND –requires extensive provisioning

January 2006Richard Stastny18 Federation ENUM This is currently how “service providers” interconnect on IP: Variants: –Private ENUM in a “walled garden” extranet (GSMA) –SIP Exchange with restricted access on the Internet (Cable providers, XConnect, SIP-IX, …) –public tree not in „e164.arpa“ (e164.info) Advantages: –No user opt-in, NO REGULATORS INVOLVED, intrinsic peering agreements, savings in CAPEX, OPEX, MM-services Disadvantages: –limited reach, –no global solution, –how to peer with other federations?

January 2006Richard Stastny19 Public Infrastructure ENUM If Infrastructure ENUM is intended to allow the mapping of any E.164 number –that can be reached via IP –even if it terminates on the PSTN –to a SIP URI, Infrastructure ENUM must be in the public DNS. But this is useless, if the resulting SIP URI cannot be reached So for Infrastructure ENUM also a global IP Interconnect (VoIP Peering) regime is required. ENUM is an applet to VoIP Peering

January 2006Richard Stastny20 Standardisation in IETF Two recent major developments in IETF regarding (VoIP) Interconnect: –ENUM WG extended scope to include Infrastructure ENUM –Voipeer BoFs to create new SPEERMINT WG Session PEERing for Multimedia INTerconnect

January 2006Richard Stastny21 Separation of Scope The ENUM WG is primarily concerned with the acquisition of Call Routing Data (CRD) e.g. a SIP URI, while the SPEERMINT WG is focused on the use of such CRD. Importantly, the CRD can be derived from ENUM (i.e., an E.164 DNS entry), or via any other mechanism available to the user.

January 2006Richard Stastny22 Scope ENUM and SPEERMINT Infrastructure ENUM Policy Database Number SIP URI Routing Parameter ENUM Lookup Policy Lookup I-ENUM SPEERMINT

January 2006Richard Stastny23 Current I-Ds in ENUM WG Carrier/Infrastrucure ENUM Requirements –draft-lind-infrastructure-enum-reqs-01 Combined User and Carrier ENUM in the e164.arpa tree –draft-haberler-carrier-enum-01 IANA Registration for an Enumservice Containing PSTN Signaling Information –draft-ietf-enum-pstn-02

January 2006Richard Stastny24 Current I-Ds in SPEERMINT Terminology for Describing VoIP Peering and Interconnect –draft-meyer-voipeer-terminology-01 Publishing SIP Peering Policy –draft-lendl-sip-peering-policy-00 –This documents proposes the use of DNS entries to publish a SIP proxy's policy for accepting incoming calls. Such published policies can be used to selectively establish peering relationships between VoIP service providers.

January 2006Richard Stastny25 Benefits in a nutshell The major benefits of Infrastructure ENUM and SPEERMINT for (VoIP) carriers and (VoIP) service providers is to save costs: Minimal CAPEX for setting up the required infrastructure to provide the routing data Minimal OPEX for maintaining routing data: –Announce the E.164 numbers you host (in ENUM) –Announce the domains you host (in DNS) –(make bilateral or multilateral peering agreements) –Query ENUM and DNS to find any other destination provider

January 2006Richard Stastny26 The End Thank you Richard Stastny ÖFEG