1. VoIP in Context Niall O’Reilly, University College Dublin IT Services HEAnet National Networking Conference 2006

2. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP in Context Strategic issues How VoIP works Market issues Interoperation with POTS Interoperation among VoIP services Strategic options

3. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP in Context What context would that be... ?

4. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP in Context Strategic issues How VoIP works Interoperation Strategic options

5. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP: Strategic Issues Global or local scope? Build, buy, or leave it to the users? Proprietary or standards-based? Branding? First, see how it works...

6. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 How VoIP works Different flavours: Standards: SIP, H.323, Services: Skype, IP-TSPs Similar requirements: Find called party Set up call Look at SIP...

7. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 SIP — direct call 192.168.19.76 10.17.243.34 INVITE sip:10.17.243.3410.17.243.34 100 Trying - ACK RTP session (voice, video, etc) Artificially simple case: caller knows where my phone is Caller’ s phone My phon e 200 OK180 Ringing -

8. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 SIP — where did he go? 10.17.243.34 Usual case: my phone is nomadic Caller’ s phone My phon e 10.97.1.5

9. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 SIP servers keep track 10.17.243.34 SIP Registrar: tracks last REGISTER event Caller’ s phone My phon e 10.97.1.5 SIP Registrar server sip.example.net Caller’s SIP server (if any)

10. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 SIP — using servers INVITE sip:niall@example.netniall@example.net ACK RTP session (voice, video, etc) Servers broker call using SIP Payload is carried peer-to-peer INVITE 200 OK Control Transport Data

11. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP compared to e- mail Submit Difference: mail servers carry payload Forward Retrieve Control & Data Transport Message queue Message store

12. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP compared to POTS Place call Difference: Payload travels over provider’s resources Set up circuit Terminate call Voice traffic over circuit Vertically integrated: no separation of Control, Data, and Transport

13. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Interoperation Technology: gateways, mapping Service management Business model POTS is centre-stage

14. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Interoperation Within POTS VoIP/POTS Within VoIP

15. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 POTS Interoperation Dial plan what can be dialled (DTMF-12) Numbering plan what can be reached (E.164) Interconnection specific number ranges — routing codes Cascaded charges terminating operator in control Fewer hops best for business Originating Operator Terminating Operator Transit Operator

16. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 POTS dominates (Metcalfe’s Law) Address (URL, number) mapping Media conversion Business relationship VoIP/POTS Interoperation

17. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 POTS uses [*#0-9] — VoIP side must accommodate Customer aliases facilitate this — Real POTS phone number (E.164) — Two-stage dialling to “extension” — extension@example.org — username@example.org VoIP/POTS Address Mapping

18. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Numbering plan POTS: numeric only VoIP: URL space or per-operator number blocks Interconnection must map (relevant parts of) numbering plans POTS to VoIP: ENUM can find matching URL for number VoIP to POTS: configuration; ENUM enables POTS bypass Successive gateways degrade quality due to lossy trans-coding VoIP/POTS Interoperation

19. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Different business model Cascaded charges on POTS side from POTS: gateway immediately (keep entire fee! from VOIP: exit to POTS late (keep bigger share of fee!) Paradox: VoIP is good for operator! VoIP/POTS Interoperation

20. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Dial plan DTMF (0-9, #, *) URL (user@domain) Numbering plan URL space Interconnection Configuration tables — maintenance! DNS is so much simpler ENUM: maps number to URL SPIT: Spam over IP Telephony Reachability decoupled from cost VoIP Interoperation Originating IP-TSP Terminating IP-TSP Internet: ISPs & Transit

21. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP Interoperation Can be just like e-mail: sip:user@domain URL drives DNS to locate destination DNS RR-types: SRV, A Provider issues: — “walled garden” vs “public park” Customer issues: NAT, firewalls

22. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP Interoperation Technology open — just like e-mail Operator business model varies — “walled garden” vs “public park” Obstacles may be significant — NAT, firewall

23. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP Interoperation Static routes support bilateral agreements VoIP “islands” may need to route via POTS — involving duration charges, double transcoding ENUM maps numbers to URLs — but not yet widely (enough) deployed Not unlike e-mail before MX records

24. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Example [Remember “!” and “%” for e-mail] *8 *4yy 8972xxxx sip:8972xxxx@example.org sip:someuser@example.org Address Mapping

25. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Encodes E.164 numbers as domain names — no “short codes” or “operator- specific” Standard algorithm to determine URL — DDDS: RFC 3401ff Not yet generally deployed ENUM

26. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Strategic options Global or local scope? Build, buy, or leave it to the users? Proprietary or standards-based? Branding?

27. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Local or global scope Technology substitution “Free” long-distance phone-calls Extend footprint of internal PBX — teleworkers, conference-goers

28. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Build, buy, or step aside In-house like e-mail linked to other administrative processes Outsource to existing IP-TSP established expertise Skype — just works walled garden with gates (charged Skype-in, -out) Gizmo — has free SIP-out

29. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Standard or proprietary Cisco, Nortel,... Skype Standard Interoperability Exploits DNS for provisioning Open Source: SER, Asterisk

30. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Branding What goes on the stationery? Skype: joe_user IP-TSP: sip:Niall.oReilly.UCD@example.ie Own-brand: sip:First.Last@ucd.ie E.164: +353-1-716-xxxx

31. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 Strategic options Global or local scope? Build, buy, or leave it to the users? Proprietary or standards-based? Branding? Know what you require, then decide

32. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 VoIP Resources Terena VoIP Cookbook (2004) Richard Stastny’s Blog http://voipandenum.blogspot.com http://voipandenum.blogspot.com iptel.org

33. Niall O’Reilly — UCD IT ServicesVoIP in Context — HEAnet NNC 2006 ?