ENUM and VoIP Peering Introduction and Overview - PowerPoint by ojf14405

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									    ENUM and VoIP Peering
       Introduction and Overview
                        marcusevans
                 Berlin, 5. June 2007


                Richard Stastny, ÖFEG*

  * The opinions expressed here may or may not be that of my company



June 2007                   Richard Stastny                     1
VoIP

• Most service providers (telco„s and others, also
  enterprises) are currently looking to implement
  VoIP in their networks and to migrate from PSTN
  to VoIP
• in 2009 VoIP will account for 90% of the market
• between 2010 and 2015 most telcos are planning
  to switch off their PSTN

     – but it is one thing to provide a VoIP solution within the
       own network (administrative domain)
     – and another to interconnect with other service providers
• using the PSTN is not an option

June 2007                   Richard Stastny                        2
VoIP Peering aka IP Interconnect


   • IP based Interconnection between
     different Administrative Domains
        – Carriers, Service Providers, Enterprises
   • including Realtime Multimedia Services
   • on behalf of end-users
   • using Public User Identities
        – dial strings
        – E.164 Numbers
        – SIP Address-of-Records (kind of SIP URI)




June 2007                Richard Stastny             3
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



June 2007                     Richard Stastny                        4
  A Simple Solution on the Internet

  RFC 3261                           DNS Server                   Location
                                                                   Server
  RFC 3263
                                   domainB.com                    user_B
                                   DNS


      domainA.com                                                  domainB.com
                 Outbound                                           Inbound
                Proxy Server                                      Proxy Server
                                              SIP



                             SIP         IETF SIP           SIP

                                         Trapezoid
                                               SIP

                                           Media (RTP)

              User Agent A                                        User Agent B

sip:user_B@domainB.com

  June 2007                               Richard Stastny                        5
RFC3263


   • RFC 3263: Locating SIP Servers
   • As an example, consider a client that wishes to resolve
     sip:user_B@domainB.com.
   • The client performs a NAPTR query for that domain, and the
     following NAPTR records are returned:
   •        ; order pref flags service regexp replacement
     IN NAPTR 50 50 "s" "SIPS+D2T" "" _sips._tcp.domainB.com.
     IN NAPTR 80 50 "s" "SIP+D2T" "" _sip._tcp.domainB.com
     IN NAPTR 90 50 "s" "SIP+D2U" "" _sip._udp.domainB.com.
   • This indicates that the server supports TLS over TCP, TCP, and
     UDP, in that order of preference.
   • Since the client supports TCP and UDP, TCP will be used,
     targeted to a host determined by an SRV lookup of
     _sip._tcp.domainB.com.
   • That lookup would return:
          ; Priority Weight Port Target
     IN SRV 0          1    5060 server1.domainB.com
     IN SRV 0          2    5060 server2.domainB.com



June 2007                    Richard Stastny                          6
Service Providers do not like this


   • This is the e-mail solution:
        – It is assuming that the server will accept any
          communication from anybody
   • Some real problems: SPIT, Identity, DoS, …
   • Service Providers need agreements
        – They will accept calls only from known partners:
            •   SLAs
            •   termination rates
            •   known customers
            •   Etc
   • One possibility: use always TLS



June 2007                       Richard Stastny              7
Some Questions to be answered


   • Does domainB accept all invites?
   • What is required by domainA and by
     domainB to establish trust?
   • Is there IP connectivity at all?
   • Do both domains use the same SIP?
   • What about termination charges?
   • Is the media stream also traversing the
     domains -> networks?



June 2007           Richard Stastny            8
What are the other options?


   • Bilateral agreements as in PSTN
        – scaling problem
        – how to interconnect to the rest?
   • Federations
        – this is what is used now
        – public and private federations
        – problem: How to interconnect between
          different federations
   • Global Interconnect
        – public or private?
        – no solution yet

June 2007                Richard Stastny         9
SPEERMINT Federations


   • I-ENUM Federations:
        – which I-ENUM DB to use to find what
          service provider (SIP URI) is hosting a
          number?
   • SPEERMINT Federations:
        – am I able to interconnect (reach) the SIP
          URI and if yes, am I not rejected?
   • Proposal to indicate the federation(s) in
     DNS NAPTRs in the domain name
     draft-lendl-speermint-federations



June 2007                Richard Stastny              10
Overall ETSI TISPAN IMS Architecture – all subsystems
                                                                                        Rf/Ro
                                Ut
                                                                                                      Rf/Ro
                      Ut                                Application Servers                                                 Charging
                                                                                                                            Functions
                                           Sh                                                                 Rf/Ro
                                                       ISC             Dh
                                UPSF                                                                                                                Iw
                                                Cx                     Dx
                                                                             SLF                                                     IWF
                                                                                                           P3                  Ib

PSTN                       IMS /
                                      Mw
Emulation (R2)             PSTN                                             Mw/Mk/Mm
                                         I/S-CSCF                                                                               IBCF           Ic
                           Simulation
                                                                  Mi                            Mk
          AGCF                   P2
                                                                         BGCF             Mk
                                           Mw




                                                                                                                                                              Other IP Networks
                                                             Mr                    Mj                                                 Gq'
                           e2                                               Mg
                                     P-CSCF                                             MGCF              SGF
                                                                  MRFC                               Ie

          P1




                                                                                                                PSTN/ISDN
                                     Gq'
                       Gq'
 Network         Gm
Attachment                            SPDF                                                                                          SPDF
                                                     Resource &        Mp                       Mn                                             Resource &
Subsystem                                            Admission                                                                                 Admission
                 e4    A-RACF
                                                     Control                                                                                   Control
          MG
                       Re             Ia
                                                                  MRFP                     T-MGF

     UE                                                                                                                             I-BGF
                      RCEF            BGF
                                                     IP Transport (Access and Core)
    CNG

   June 2007                                                  Richard Stastny                                                                            11
                                                                                                                                           -
The SPEERMINT Generalized View

            +-------------+-------------------------------------+------------+
            |              \                Assisted Domain                            /        |
            |                \                                                       /          |
            |                  \          +------+ +---+--+                        /            |
            |                    \        + A-LS + + A-SM |                      /              |
            |                      \      +------+ +-----++                     /               |
            |                        \    +------+ +------+                   /                 |
            |           +------+ \        | A-SBE| | A-DBE|                  /+------+          |
            |     +-----+ O-LS + \ +------+ +------+ / + T-LS +-----+                           |
            |     |     +------+       \                                    / +------+     |    |
            |     |                     \                                 /                |    |
            |     |                       \                             /                  |    |
            |     |     +------+            \                         /       +------+     |    |
            |     |     | O-SBE+              \                     /         + T-SBE|     |    |
            |     |     +---+--+                \                 /           +------+     |    |
            |     |         |                     \             /                          |    |
            |     |         |                       \         /                            |    |
            |     |     +---+--+                      \     /                 +------+     |    |
            |     +-----+ O-SM |                        \ /                   | T-SM +-----+    |
            |           +-----++                         +                    ++-----+          |
            | +----+             |                       |                     |         +----+ |
            | |O-UE+---------+                           |                     +---------+T-UE| |
            | +----+             +------+                |           +------+            +----+ |
            |                   | O-DBE|==============| T-DBE|                                  |
            |                   +------+                 |           +------+                   |
            |     Originating Domain                     |               Terminating Domain     |
            +----------------------------------------------------------------+


June 2007                                 Richard Stastny                                           12
Private Federations

   • GSMAs IPX is potentially a large federation,
     but still in planning stage (3GPP Rel7
     onwards)
   • Others: XConnect, SPIDER, CableLabs
   • National private federations
        – UK, Netherlands, US, …
   • TISPAN has not decided yet:
        – make an own federation
        – use global I-ENUM
        – join IPX (especially now after 3GPP/TISPAN merger)
   • Global I-ENUM
        – public or private?


June 2007                      Richard Stastny                 13
A (large, private) Federation




June 2007        Richard Stastny   14
What are the proposals?


   • Bi-lateral peering agreements
        – may be used for heavy traffic relations
        – may use direct links
        – does not scale
   • Federations
        – over the Internet or
        – in extranets
   • Transit providers
        – only for signalling
        – or also for media -> redoing the PSTN




June 2007                   Richard Stastny         15
Next complication


   • End users to not use SIP URIs
   • they use phone numbers
   • phone numbers are (target) names on
     the Internet
   • target names need to be translated
     (mapped) to target addresses
   • one possibility -> ENUM
   • E.164 to AoR translation using the DNS



June 2007           Richard Stastny           16
ENUM as defined by the IETF

   • 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. http://enum.nic.at )



June 2007                   Richard Stastny                     17
ENUM in a nutshell


• take an E.164 phone number          +43 720 203 211


• turn it into a FQDN    1.1.2.3.0.2.0.2.7.3.4.e164.arpa.

• query the DNS (for NAPTR)

• returns list of URIs              sip:richard@iphone.at
                               mailto:richard.stastny@oefeg.at
                               sms tel:+436644204100
  IN NAPTR 100 100 "u" “E2U+sip“ !^.*$!SIP:richard@iphone.at! .


June 2007                 Richard Stastny                        18
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
   • Implemented by RIPE NCC and ITU-T
        – via the Interim Procedures
June 2007               Richard Stastny              19
ENUM Implementations
          Delegations in e164.arpa as of May 31, 2007
•   30      Greece
                                                 •    246    Diego Garcia
•   31      Netherlands
                                                 •    247    Ascension
•   33      France            Trial closed
                                                 •    262    Reunion (fr)
•   350     Gibraltar
                                                 •    290    Saint Helena
•   353     Ireland
                                                 •    508    St. Pierre and Miquelon (fr)
•   354     Iceland
                                                 •    55     Brazil
•   358     Finland
                                                 •    590    Guadeloupe (fr)
•   359     Bulgaria
                                                 •    594    French Guyana
•   36      Hungary
                                                 •    596    Martinique
•   370     Lithuania
                                                 •    61     Australia                 Trial
•   374     Armenia
                                                 •    62     Indonesia                 Trial
•   386     Slovenia
                                                 •    63     Philippines               Trial
•   39      Italy
                                                 •    66     Thailand
•   40      Romania
                                                 •    65     Singapore                 Trial
•   41      Switzerland       Trial
                                                 •    81     Japan                     Trial
•   420     Czech Republic
                                                 •    82     Korea                     Trial
•   421     Slovakia          Trial
                                                 •    84     Vietnam
•   423     Liechtenstein     Trial
                                                 •    86     China                     Trial
•   43      Austria
                                                 •    88234 Global Networks Switzerland AG
•   44      UK                Trial
                                                 •    87810 VISIONng UPT
•   46      Sweden
                                                 •    971    UAE
•   47      Norway
•   48      Poland
•   49      Germany
                                             •       1   North America (US, CA, Jamaika)
                                             •       additional Asian countries (Taiwan…) have trials,
                                                     but not in .arpa

                             http://www.ripe.net/enum/request-archives/
June 2007                               Richard Stastny                                             20
Infrastructure 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
    Infrastructure ENUM
June 2007              Richard Stastny       21
I-ENUM is Solving Two Problems


   • Number Portability
        – provides the hosting (destination) service
          provider (administrative Domain)
   • IP Interconnect
        – provides the ingress point to the destination
          network
        – can also be derived from the hosting service
          provider




June 2007                Richard Stastny                  22
Number Portability


  • Different options implemented on PSTN
      – onward routing, drop back,
        query on release, all call query (ACQ)
  • Some countries use centralized databases
  • It is easy to use this data also for I-ENUM
    to provide NP also on IP




June 2007               Richard Stastny           23
NP in NGNs with I-ENUM


• In NGNs ACQ is the only valid option
• So what is required:
     – National administrative NP procedures remain the same
     – A centralized DB is set up, containing all number range
       holders (NRH) (LIDB)
       PLUS
       all ported numbers (LNP-DB)
• NGNs use direct routing based on ACQ
     – but must be able to support the national implementation
       (e.g. onward routing)
     – i.e. they may receive calls as donor network for ported
       out numbers
     – they query I-ENUM and route the call to the destination



June 2007                  Richard Stastny                       24
The Infrastructure ENUM options


• What are the options with I-ENUM?

• Carrier (Operator, Private) Infrastructure
  ENUM
     – closed
• Federation Infrastructure ENUM
     – closed or open
• Global Infrastructure ENUM
     – closed or open



June 2007               Richard Stastny        25
Private Infrastructure ENUMs

   • Also called:
        – Operator ENUM
        – Enterprise ENUM
        – Carrier ENUM
   • Used by one service provider within his own
     network
   • May be downloaded from a centralized registry
   • Advantages:
        – No user opt-in, NO REGULATORS INVOLVED,
        – very secure
   • Disadvantages:
        – Service provider responsible for all data
        – Savings in OPEX questionable
        – no global solution,

June 2007                    Richard Stastny          26
Federation ENUMs

   • This is currently how “service providers”
     interconnect:
   • Variants:
        – Closed ENUM in a “walled garden” extranet (GSMA)
        – SIP Exchange with restricted access on the Internet
          (Cable providers, XConnect, SIP-IX, SPIDER, …)
        – open 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?

June 2007                   Richard Stastny                     27
Why Global Infrastructure ENUM?
   • All types of private and federated ENUMs have serious
     disadvantages:
        – limited reach,
        – no global solution,
        – how to peer with other federations?
   • Only numbers from providers participating in the given
     federation can be reached
   • To enable global reachability on IP, a single, common
     and global tree is required.
   • This tree may be open or closed
   • The first goal of Infrastructure ENUM is to create an
     anchor place where any E.164 number can be found and
     will:
        – either be mapped directly to an ingress point of the
          destination network,
        – or at least hints can be found in which private E.164
          resolution spaces the number can be resolved.

June 2007                     Richard Stastny                     28
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)


June 2007                     Richard Stastny                           29
Another open issue: dial strings


• Users may enter E.164 numbers or
  SIP AoRs
• but normally users enter dial strings
• these are dependant of a dial plan e.g.:
     – mobile users use national numbers
     – fixed users use local numbers
• need to be processed and normalized to
  target names (e.g. E.164 numbers)
• the full picture of Number/Name to
  Address Resolution (NAR) in TISPAN

June 2007              Richard Stastny       30
Numbering/Naming/Address/
Routing Resolution
                        Dial string

                Process                  Dial Plan
              Dialed Digits              Number Plan

    E.164               Target Name (TEL, URN)
                                        Translation
            Name to Address             Service
                                        (ENUM, LoST,
              Translation
                                        etc.)
      SIP
      URI                Target Address (SIP URI)
                                        Routing
                 Route                  Tables
             Determination              (DNS,
                                        configured, )
June 2007         Richard Stastny                   31
User Input


   • A user may enter either
        – a dialstring
          sip:019793321@home.net;user=dialstring
        – an E.164 number in the international format
          tel:+4319793321
        – a SIP URI (Address-of-Record)
          sip:+4319793321@silver.net;user=phone
          sip:charly@mobilkom.at
        – a Service URN
          urn:service:sos.police



June 2007               Richard Stastny                 32
Dial String Processing


   • If a dialstring is transmitted to the
     home proxy (S-CSCF)
   • the dialstring must be translated to a
     target name
        1. E.164 number (name)
        2. Non-E.164 number
            – Service URN
            – SIP URI
            – whatever




June 2007                   Richard Stastny   33
Non-E.164 Numbers

1. all numbers that can only be used nationally,
   also E.164 numbers that are by commercial or
   other reason not reachable from abroad, e.g.
   national freephone number not open on the
   international level.
2. short codes, e.g. emergency number 112 and
   other short codes
3. local special purpose numbers
4. international special purpose numbers used
   nationally
5. network-specific numbers
6. national (significant) numbers with excessive
   length (i.e. where digits in [CC + N(S)N] > 15)
7. private numbers in a private/corporate
   numbering plan (e.g. PABX, ISPBX, IP-PBX)
8. location dependent numbers
June 2007            Richard Stastny                 34
What are the Open Issues?


   • The Internet is based on end-to-end
     communication and best effort, no central
     intelligence
        – this causes also a lot of problems (SPAM, DoS,
          spoofing, phishing, …)
   • The PSTN has central control, QoS and a
     different business model,
        – but it is a one trick pony
   • The dream of the NGN
        – take the benefits of the PSTN (especially the
          business model) and move it over to IP technology




June 2007                    Richard Stastny                  35
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




June 2007                     Richard Stastny                     36
                 Thank you

                  Richard Stastny
                          ÖFEG
                  +43 664 420 4100
                richard.stastny@oefeg.at
            http://voipandenum.blogspot.com


June 2007              Richard Stastny        37

								
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