1. www.convergencetechnologycenter.org DUE 402356 Adapting Legacy Phone Systems to VoIP Vincente DIngianni Director of Professional Services Binary Systems, Inc. vincente@binary-systems.com

2. www.convergencetechnologycenter.org 2 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

3. www.convergencetechnologycenter.org 3 The Legacy PSTN Public Switched Telephone Network Enterprise Network PSTN Enterprise NetworkSubscribers

4. www.convergencetechnologycenter.org 4 Whats Inside the PSTN? Class 4 Tandem Switch Class 5 End Office Switch Enterprise Network Subscribers Enterprise Network Public Switched Telephone Network

5. www.convergencetechnologycenter.org 5 Forgetting the Complexity Public Switched Telephone Network Enterprise Network PSTN Enterprise NetworkSubscribers All Routing Logic is managed by the Service Providers Network – Not yours.

6. www.convergencetechnologycenter.org 6 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

7. www.convergencetechnologycenter.org 7 Enter the IP Network Enterprise Network PSTN Enterprise NetworkSubscribers IP Network Public Internet or Private WAN

8. www.convergencetechnologycenter.org 8 Focusing on VoIP Enterprise Network Subscribers IP Network Public Internet or Private WAN VoIP gives you the option to take control of your Communication Network

9. www.convergencetechnologycenter.org 9 Whats Inside an IP Network? Enterprise Network Subscribers Public Internet or Private WAN Firewall Routers In most cases, IP Routing Logic is still managed by a Service Providers Network – Not yours

10. www.convergencetechnologycenter.org 10 Forgetting the Complexity Enterprise Network Subscribers IP Network Public Internet or Private WAN VoIP Communication Protocols, such as SIP & H.323, allow control of your communication routing without interfering with the Service Providers Network

11. www.convergencetechnologycenter.org 11 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

12. www.convergencetechnologycenter.org 12 Fax -Demodulation - Handshaking Signaling Interworking VoIP PSTN IP Processing -IP - TCP - UDP - RTP PSTN PBX Ethernet PPP Frame Relay ATM IP Voice Applications/ Management Processing Signaling Interworking VoIP PSTN Fax – Demodulation – Handshaking Voice -Compression - Echo Cancellation -Silence Suppression PSTN Ports -Analog C.O -T1/E1 IP Network VoIP Media Gateways provide the bridge between Legacy Phone Systems and VoIP What are VoIP Media Gateways?

13. www.convergencetechnologycenter.org 13 PSTN PBX Ethernet PPP Frame Relay ATM IP Voice IP Network Vega 50 Analog VoIP Gateway Analog Ports for FXS or FXO Signaling Supports PSTN/PBX or Telephone Lines Connection to the IP Network Via 100Base-T Ethernet Interface SIP, H.323 Selectable Coders Per Channel: G.711, G.723, G.729 T.38 Fax Relay Analog VoIP Gateways

14. www.convergencetechnologycenter.org 14 PSTN PBX Ethernet PPP Frame Relay ATM IP Voice IP Network Digital Trunking VoIP Gateways Vega 400 Trunking VoIP Gateway Supports PSTN/PBX Digital Trunks T1 / E1 ISDN, North American CAS, R2 Connection to the IP Network Via 100Base-T Ethernet Interface SIP, H.323 Selectable Coders Per Channel: G.711, G.723, G.729 T.38 Fax Relay

15. www.convergencetechnologycenter.org 15 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

16. www.convergencetechnologycenter.org 16 Bridging the Networks PSTN IP Network VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway Ethernet Digital Trunks FXO Lines

17. www.convergencetechnologycenter.org 17 Bridging the Networks (cont.) Firewall Routers IP Network Ethernet VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway

18. www.convergencetechnologycenter.org 18 Bridging the Networks (cont.) PSTN Class 4 Tandem Switch Class 5 End Office Switch FXO Lines Digital Trunks VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway

19. www.convergencetechnologycenter.org 19 PSTN IP Network Ethernet User Side Digital Trunks Enterprise Network Private Extensions FXS Lines Network Side Digital Trunks FXO Lines VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway Bridging Public and Private Networks

20. www.convergencetechnologycenter.org 20 The Leaky PBX PSTN IP Network Ethernet Enterprise Network Network Side Digital Trunks FXO Lines Enterprise Network Using Legacy PBX Routing functionality, users may dial a prefix to bypass the PSTN Calls are routed via VoIP to remote locations/countries Standard PSTN Toll charges are bypassed Enterprising Enterprises resell the ability to terminate calls on their local PSTN connection so other VoIP users can benefit (not necessarily legal)

21. www.convergencetechnologycenter.org 21 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

22. www.convergencetechnologycenter.org 22 PSTN IP Network Ethernet Enterprise Network Network Side Digital Trunks FXO Lines Enterprise Network Calculate the number of calls that you will be making simultaneously over your IP connection Estimate approximately 80-90 kbps uncompressed per call A T3 (28 T1s) of voice will fill a 100 Mb Ethernet link Bandwidth Requirements

23. www.convergencetechnologycenter.org 23 Most cable modems provide asymmetrical bandwidth 3 Mb downstream is popular 256K upstream is typical Dont expect to force an entire trunk worth of voice through a cable modem or DSL Vega 400 Trunking VoIP Gateway E1 PRI Cable Modem 256K Upstream Bandwidth Requirements

24. www.convergencetechnologycenter.org 24 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

25. www.convergencetechnologycenter.org 25 PBX/CO The Switch provides the Talk Battery to power a phone The switch provides the dial tone The phone generates the digits POTS Line POTS Line connected to a PBX/CO

26. www.convergencetechnologycenter.org 26 Foreign Exchange Office (FXO) Emulates a telephone set connects to a standard line side interface of the PBX or central office Private Network PBX/CO FXO Foreign Exchange Office (FXO) This is the way that Interexchange carriers were forced to connect with AT&T before equal access Carriers would purchase simple lines in each city to create a POP These lines were directly connected into their switching networks Subscribers dialed 7-digit access numbers to receive dial tone from the carrier

27. www.convergencetechnologycenter.org 27 Foreign Exchange Station (FXS) Emulates a switch port connects to a standard telephone line Signaling can be loop start or ground start Private Network FXS Foreign Exchange Station (FXS) POTS Line

28. www.convergencetechnologycenter.org 28 Foreign Exchange Office (FXO) Emulates a telephone set connects to a standard line side interface of the PBX/CO Foreign Exchange Station (FXS) Emulates a switch port connects to a standard telephone line Signaling can be loop start or ground start Private Network PBX/CO FXO FXS Combination of FXO/FXS allows a remote station to appear as a standard line: POTS Line Extensions use a combination of FXO and FXS

29. www.convergencetechnologycenter.org 29 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

30. www.convergencetechnologycenter.org 30 Public Switched Telephone Network Enterprise Network PSTN Enterprise NetworkSubscribers Remote VoIP Users

31. www.convergencetechnologycenter.org 31 PSTN Subscribers Enterprise Network Remote Lines

32. www.convergencetechnologycenter.org 32 PSTN Subscribers Enterprise Network IP Network Public Internet or Private WAN Cable Modems or DSL can be used for low numbers of remote users. Adding a VoIP Network

33. www.convergencetechnologycenter.org 33 Public Internet or Private WAN Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway PSTN Subscribers Enterprise Network IP Network Adding VoIP Gateways

34. www.convergencetechnologycenter.org 34 Public Internet or Private WAN PSTN IP Network Subscribers Enterprise Network Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway Bypassing the PSTN

35. www.convergencetechnologycenter.org 35 Public Internet or Private WAN IP Network Subscribers Enterprise Network Call routing between VoIP Gateways is configured locally. Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway Remote User Connected via VoIP

36. www.convergencetechnologycenter.org 36 Analog FXO VoIP Gateway 192.168.1.123 Enterprise Network Configuring Local FXO Extensions

37. www.convergencetechnologycenter.org 37 Analog FXO VoIP Gateway 192.168.1.123 Enterprise Network Configuring Local FXO Routing

38. www.convergencetechnologycenter.org 38 Analog FXS VoIP Gateway 192.168.1.202 Subscribers Configuring Remote FXS Extensions

39. www.convergencetechnologycenter.org 39 Analog FXS VoIP Gateway 192.168.1.202 Subscribers Configuring Remote FXS Routing

40. www.convergencetechnologycenter.org 40 Public Internet or Private WAN IP Network Subscribers Enterprise Network Subscribers maintain all feature functionality as local users on the PBX. Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway Remote Users connected via VoIP

41. www.convergencetechnologycenter.org 41 IP Network Subscribers Enterprise Network IP Phones An IP phone is simply a single-port VoIP media gateway Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway Adding IP-Only Users

42. www.convergencetechnologycenter.org 42 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

43. www.convergencetechnologycenter.org 43 In-Band Signaling CAS – Channel Associated Signaling R2 E&M Wink Start FGD D-Channel Trunk Signaling Methods Out-of-Band Signaling ISDN / Q.931 SS7 Bearer Channel Combined Voice and Signaling Channel

44. www.convergencetechnologycenter.org 44 D-Channel Network vs. User Side ISDN Network side ISDN Network side ISDN provides a standard PRI interface to a PBX and mimics the behavior of legacy phone switches User Side ISDN User side ISDN provides a standard ISDN PRI interface to the Public Switched Telephone Network (PSTN) Bearer Channel PSTN Network Side User Side Clock Timing

45. www.convergencetechnologycenter.org 45 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

46. www.convergencetechnologycenter.org 46 Public Switched Telephone Network Enterprise Network PSTN Enterprise NetworkSubscribers Remote VoIP Locations – PSTN Connectivity

47. www.convergencetechnologycenter.org 47 PSTN Enterprise Network Network Side User Side ISDN PRI Remote VoIP Locations – Connecting Locations via PSTN

48. www.convergencetechnologycenter.org 48 IP Network PSTN Enterprise Network Remote VoIP Locations - Adding VoIP

49. www.convergencetechnologycenter.org 49 PSTN Enterprise Network IP Network Remote VoIP Locations – Adding VoIP

50. www.convergencetechnologycenter.org 50 PSTN IP Network Enterprise Network Network Side User Side ISDN PRI Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway Remote VoIP Locations – Adding VoIP Gateways

51. www.convergencetechnologycenter.org 51 IP Network Enterprise Network Network Side User Side ISDN PRI Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway Remote VoIP Locations – PSTN Bypass

52. www.convergencetechnologycenter.org 52 IP Network Enterprise Network IP Phones Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway Remote VoIP Locations – Adding IP- Only Users

53. www.convergencetechnologycenter.org 53 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

54. www.convergencetechnologycenter.org 54 Do I Need a Softswitch? Ask these questions: Does your existing PBX have the features that you need? What VoIP control protocols do your gateways/endpoints support? How many VoIP gateways/endpoints do you need?

55. www.convergencetechnologycenter.org 55 Remote VoIP users can transparently utilize features from the legacy PBX/switch Virtual Private Networks for Voice can be created via existing PBX Routing Tables Features such as T.38 Fax Relay and RFC 2833 digit transport provide reliable communication over low bandwidth connections Does Your Existing PBX Have the Features That You Need?

56. www.convergencetechnologycenter.org 56 MGCP and MEGACO are Master-Slave protocols MGCP and MEGACO require a Call Agent/Softswitch to instruct the Endpoint to perform all functionality If communication with the Call Agent is lost, the endpoint cannot function These protocols require a Softswitch SIP and H.323 are peer-to-peer protocols SIP and H.323 gateways offer internal routing tables and features that often rival the legacy PBX or Key System itself If communication with the Proxy/Gatekeeper/Softswitch is lost, internal routing tables may be used. For example, 911 SIP is continually evolving to support next generation features What VoIP Control Protocols do Gateways Support?

57. www.convergencetechnologycenter.org 57 Softswitches, SIP proxies, and H.323 gatekeepers provide a single point of configuration for advanced network features IP Network Enterprise Network IP Phone Softswitch Feature Server Vega 400 Trunking VoIP Gateway Vega 400 Trunking VoIP Gateway How Many VoIP Endpoints Do You Have?

58. www.convergencetechnologycenter.org 58 What Well Cover… Whats inside the PSTN? Whats inside the IP network? VoIP gateways Connecting the IP network to the PSTN Bandwidth Remote PSTN users – The Old Way Remote VoIP users – The New Way Remote PSTN locations – The Old Way Remote VoIP locations – The New Way Do I need a Softswitch? Do I need a VoIP carrier?

59. www.convergencetechnologycenter.org 59 PSTN IP Network Ethernet Enterprise Network Network Side Digital Trunks FXO Lines Enterprise Network VoIP Carriers provide alternate IP-based call routing to remote endpoints via the public Internet Calls are routed via VoIP to remote locations/countries and standard PSTN Toll charges are bypassed VoIP Carriers Softswitch / Feature Server Do I Need a VoIP Carrier? Vega 400 Trunking VoIP Gateway Vega 50 Analog VoIP Gateway

60. www.convergencetechnologycenter.org 60 Can I Cut the Cord to the PSTN? IP Network Ethernet Enterprise Network If you are satisfied with the reliability of your high-speed internet provider and VoIP carriers feature set and destination choices, you may choose to cut the cord But first, ensure that your gateways, as well as, your VoIP Carriers network support T.38 faxes and a compatible modem passthrough functionality VoIP Carriers Softswitch / Feature Server Ethernet Network Side Digital Trunks Vega 400 Trunking VoIP Gateway Vega 50 Analog VoIP Gateway

61. www.convergencetechnologycenter.org 61 Key Points to Remember Dont underestimate the complexity of the PSTN and IP network Choose the right VoIP Endpoint for your application Follow the industry – Use SIP for new installations Analog FXS or FXO Gateways for lines and key systems Digital Trunking Gateways for PBXs IP phones for new user installations Be sure you can support T.38 for faxes and bypass for modems Be sure you have a big enough IP pipe to add voice SIP and H.323 VoIP Gateways can provide stand-alone routing and feature functionality Use a Softswitch to manage numerous gateways and advanced features VoIP carriers can provide connectivity beyond your private network Yes, you can cut the cord to the PSTN!