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Adapting Legacy Phone Systems to VoIP [ppt]
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Adapting Legacy Phone Systems to VoIP [ppt]

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  • Definition: A VoIP Media Gateway is any device, such as a circuit switch, IP gateway that converts data from the format required for one type of network to the format required for another. A media gateway might terminate channels from a PSTN analog or digital network as well as from a packet switched network.
  • If you have ever used a “Pre-Paid Calling Card”, then there is a good chance that your call has terminated on a Leaky PBX.
  • There are two different methods of signaling the first is the IN-Band which means that the signaling is sent within the voice channel. The second method is the Out-of-Band this technique uses a separate channel for signaling this is done for example in ISDN protocol by D channel which is dedicated only for control and the voice is send in B (bearer) channel alone.
  • Transcript

    • 1. Adapting Legacy Phone Systems to VoIP Vincente D’Ingianni Director of Professional Services Binary Systems, Inc. [email_address]
    • 2. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. The Legacy PSTN Public Switched Telephone Network Enterprise Network PSTN Enterprise Network Subscribers Subscribers
    • 4. What’s Inside the PSTN? Class 4 Tandem Switch Class 5 End Office Switch Enterprise Network Subscribers Subscribers Enterprise Network Public Switched Telephone Network
    • 5. Forgetting the Complexity Public Switched Telephone Network Enterprise Network PSTN Enterprise Network Subscribers Subscribers All Routing Logic is managed by the Service Provider’s Network – Not yours.
    • 6. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Enter the IP Network Enterprise Network PSTN Enterprise Network Subscribers Subscribers Public Internet or Private WAN IP Network
    • 8. Focusing on VoIP Enterprise Network Enterprise Network Subscribers Subscribers Public Internet or Private WAN VoIP gives you the option to take control of your Communication Network IP Network
    • 9. What’s Inside an IP Network? Enterprise Network Enterprise Network Subscribers Subscribers Public Internet or Private WAN Firewall Firewall Routers Routers Routers In most cases, IP Routing Logic is still managed by a Service Provider’s Network – Not yours
    • 10. Forgetting the Complexity Enterprise Network Enterprise Network Subscribers Subscribers 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 IP Network
    • 11. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. What are VoIP Media Gateways?
      • 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
      IP Network VoIP Media Gateways provide the bridge between Legacy Phone Systems and VoIP
      • PSTN
      • Ports
      • Analog
      • C.O
      • T1/E1
    • 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. Digital Trunking VoIP Gateways PSTN PBX Ethernet PPP Frame Relay ATM IP Voice IP Network 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. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Bridging the Networks PSTN IP Network VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway Ethernet Ethernet Digital Trunks FXO Lines
    • 17. Bridging the Networks (cont.) Firewall Firewall Routers Routers Routers IP Network Ethernet Ethernet VegaStream Trunking VoIP Gateway VegaStream Analog VoIP Gateway
    • 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. Bridging Public and Private Networks PSTN IP Network Ethernet 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
    • 20. The “Leaky” PBX PSTN IP Network Ethernet 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. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Bandwidth Requirements PSTN IP Network Ethernet 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
    • 23.
      • Most cable modems provide asymmetrical bandwidth
        • 3 Mb downstream is popular
        • 256K upstream is typical
      • Don’t expect to force an entire trunk worth of voice through a cable modem or DSL
      Bandwidth Requirements Vega 400 Trunking VoIP Gateway E1 PRI Cable Modem 256K Upstream
    • 24. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. POTS Line connected to a PBX/CO 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
    • 26. Foreign Exchange Office (FXO)
      • 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
      • 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. Foreign Exchange Station (FXS) 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 POTS Line
    • 28. Extensions use a combination of FXO and FXS
      • 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
    • 29. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Remote VoIP Users Public Switched Telephone Network Enterprise Network PSTN Enterprise Network Subscribers Subscribers
    • 31. Remote Lines PSTN Subscribers Enterprise Network
    • 32. Adding a VoIP Network PSTN Subscribers Enterprise Network Public Internet or Private WAN Cable Modems or DSL can be used for low numbers of remote users. IP Network
    • 33. Adding VoIP Gateways Public Internet or Private WAN Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway PSTN Subscribers Enterprise Network IP Network
    • 34. Bypassing the PSTN Public Internet or Private WAN PSTN Subscribers Enterprise Network Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway IP Network
    • 35. Remote User Connected via VoIP Public Internet or Private WAN Subscribers Enterprise Network Call routing between VoIP Gateways is configured locally. Vega 50 Analog FXO VoIP Gateway Vega 50 Analog FXS VoIP Gateway IP Network
    • 36. Configuring Local FXO Extensions Analog FXO VoIP Gateway 192.168.1.123 Enterprise Network
    • 37. Configuring Local FXO Routing Analog FXO VoIP Gateway 192.168.1.123 Enterprise Network
    • 38. Configuring Remote FXS Extensions Analog FXS VoIP Gateway 192.168.1.202 Subscribers
    • 39. Configuring Remote FXS Routing Analog FXS VoIP Gateway 192.168.1.202 Subscribers
    • 40. Remote Users connected via VoIP Public Internet or Private WAN 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 IP Network
    • 41. Adding IP-Only Users 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 IP Network
    • 42. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Trunk Signaling Methods
      • In-Band Signaling
        • CAS – Channel Associated Signaling
        • R2
        • E&M Wink Start
        • FGD
      D-Channel
      • Out-of-Band Signaling
        • ISDN / Q.931
        • SS7
      Bearer Channel Combined Voice and Signaling Channel
    • 44. Network vs. User Side ISDN D-Channel
      • 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. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Remote VoIP Locations – PSTN Connectivity Public Switched Telephone Network Enterprise Network PSTN Enterprise Network Subscribers Subscribers
    • 47. Remote VoIP Locations – Connecting Locations via PSTN PSTN Enterprise Network Enterprise Network Network Side User Side User Side ISDN PRI ISDN PRI
    • 48. Remote VoIP Locations - Adding VoIP PSTN Enterprise Network Enterprise Network IP Network
    • 49. Remote VoIP Locations – Adding VoIP PSTN Enterprise Network Enterprise Network IP Network
    • 50. Remote VoIP Locations – Adding VoIP Gateways PSTN Enterprise Network Enterprise Network Network Side Network Side User Side User Side ISDN PRI ISDN PRI Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway IP Network
    • 51. Remote VoIP Locations – PSTN Bypass Enterprise Network Enterprise Network Network Side Network Side User Side User Side ISDN PRI ISDN PRI Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway IP Network
    • 52. Remote VoIP Locations – Adding IP-Only Users Enterprise Network Enterprise Network IP Phones Vega 400 PRI VoIP Gateway Vega 400 PRI VoIP Gateway IP Network
    • 53. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. 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.
      • 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.
      • 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.
      • Softswitches, SIP proxies, and H.323 gatekeepers provide a single point of configuration for advanced network features
      How Many VoIP Endpoints Do You Have? Enterprise Network Enterprise Network IP Phone IP Phone Softswitch Feature Server Vega 400 Trunking VoIP Gateway Vega 400 Trunking VoIP Gateway IP Network
    • 58. What We’ll Cover…
      • What’s inside the PSTN?
      • What’s 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. Do I Need a VoIP Carrier? PSTN IP Network Ethernet 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 Carrier’s Softswitch / Feature Server Vega 400 Trunking VoIP Gateway Vega 50 Analog VoIP Gateway
    • 60. Can I Cut the Cord to the PSTN? IP Network Ethernet Enterprise Network Enterprise Network
      • If you are satisfied with the reliability of your high-speed internet provider and VoIP carrier’s feature set and destination choices, you may choose to cut the cord
      • But first, ensure that your gateways, as well as, your VoIP Carrier’s network support T.38 faxes and a compatible modem passthrough functionality
      VoIP Carrier’s Softswitch / Feature Server Ethernet Network Side Digital Trunks Vega 400 Trunking VoIP Gateway Vega 50 Analog VoIP Gateway
    • 61. Key Points to Remember
      • Don’t 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!