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Adapting Legacy Phone Systems to VoIP. Vincente D’Ingianni Director of Professional Services Binary Systems, Inc. vincente@binary-systems.com. 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
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Adapting Legacy Phone Systems to VoIP Vincente D’Ingianni Director of Professional Services Binary Systems, Inc. vincente@binary-systems.com
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?
The Legacy PSTN Subscribers Enterprise Network PSTN Public Switched Telephone Network Enterprise Network Subscribers
What’s Inside the PSTN? Subscribers Enterprise Network Class 5 End Office Switch Class 4 Tandem Switch Public Switched Telephone Network Enterprise Network Subscribers
Forgetting the Complexity All Routing Logic is managed by the Service Provider’s Network – Not yours. Subscribers Enterprise Network PSTN Enterprise Network Subscribers Public Switched Telephone Network
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?
IP Network Enter the IP Network Subscribers Enterprise Network PSTN Enterprise Network Subscribers Public Internet or Private WAN
IP Network Focusing on VoIP Subscribers Enterprise Network VoIP gives you the option to take control of your Communication Network Enterprise Network Subscribers Public Internet or Private WAN
What’s Inside an IP Network? In most cases, IP Routing Logic is still managed by a Service Provider’s Network – Not yours Subscribers Enterprise Network Firewall Routers Routers Routers Firewall Enterprise Network Subscribers Public Internet or Private WAN
IP Network Forgetting the Complexity VoIP Communication Protocols, such as SIP & H.323, allow control of your communication routing without interfering with the Service Providers Network Subscribers Enterprise Network Enterprise Network Subscribers Public Internet or Private WAN
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?
PSTN • Ports • Analog • C.O • T1/E1 What are VoIP Media Gateways? VoIP Media Gateways provide the bridge between Legacy Phone Systems and VoIP Applications/ Management Processing PSTN • Voice • Compression • Echo • Cancellation • Silence • Suppression • IP • Processing • IP • TCP • UDP • RTP IP Voice IP Network Ethernet PPP Frame Relay ATM • Fax • Demodulation • Handshaking • Fax • Demodulation • Handshaking Signaling Interworking VoIP <-> PSTN Signaling Interworking VoIP<-> PSTN PBX
Analog VoIP Gateways PSTN Vega 50 Analog VoIP Gateway IP Voice IP Network Ethernet PPP Frame Relay ATM • 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 PBX
Digital Trunking VoIP Gateways PSTN Vega 400 Trunking VoIP Gateway IP Voice IP Network Ethernet PPP Frame Relay ATM • 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 PBX
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?
Bridging the Networks FXO Lines Digital Trunks PSTN VegaStream Analog VoIP Gateway VegaStream Trunking VoIP Gateway IP Network Ethernet Ethernet
Bridging the Networks (cont.) Firewall VegaStream Analog VoIP Gateway VegaStream Trunking VoIP Gateway Routers Routers Ethernet Ethernet Routers Firewall IP Network
Bridging the Networks (cont.) PSTN Class 5 End Office Switch FXO Lines Digital Trunks VegaStream Analog VoIP Gateway VegaStream Trunking VoIP Gateway Class 4 Tandem Switch
Bridging Public and Private Networks FXO Lines User Side Digital Trunks PSTN VegaStream Analog VoIP Gateway VegaStream Trunking VoIP Gateway IP Network Ethernet Ethernet Network Side Digital Trunks FXS Lines Private Extensions Enterprise Network
The “Leaky” PBX Enterprise Network Enterprise Network FXO Lines PSTN Network Side Digital Trunks IP Network Ethernet Ethernet • 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)
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?
Bandwidth Requirements Enterprise Network Enterprise Network FXO Lines PSTN Network Side Digital Trunks IP Network Ethernet Ethernet • 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 • 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 Cable Modem 256K Upstream Vega 400 Trunking VoIP Gateway E1 PRI
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?
POTS Line connected to a PBX/CO PBX/CO POTS Line • The Switch provides the “Talk Battery” to power a phone • The switch provides the dial tone • The phone generates the digits
Foreign Exchange Office (FXO) PBX/CO FXO Private Network • Foreign Exchange Office (FXO) • Emulates a telephone set connects to a standard line side interface • of the PBX or central office • 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
Foreign Exchange Station (FXS) FXS POTS Line Private Network Foreign Exchange Station (FXS) Emulates a switch port connects to a standard telephone line Signaling can be loop start or ground start
Extensions use a combination of FXO and FXS PBX/CO FXO FXS POTS Line Private Network Combination of FXO/FXS allows a remote station to appear as a standard line: • 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
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?
Remote VoIP Users Subscribers Enterprise Network PSTN Public Switched Telephone Network Enterprise Network Subscribers
Remote Lines Subscribers Enterprise Network PSTN
IP Network Adding a VoIP Network Subscribers Enterprise Network PSTN Public Internet or Private WAN Cable Modems or DSL can be used for low numbers of remote users.
IP Network Adding VoIP Gateways Subscribers Enterprise Network PSTN Vega 50 Analog FXS VoIP Gateway Vega 50 Analog FXO VoIP Gateway Public Internet or Private WAN
IP Network Bypassing the PSTN Subscribers Enterprise Network PSTN Vega 50 Analog FXS VoIP Gateway Vega 50 Analog FXO VoIP Gateway Public Internet or Private WAN
IP Network Remote User Connected via VoIP Subscribers Enterprise Network Call routing between VoIP Gateways is configured locally. Vega 50 Analog FXS VoIP Gateway Vega 50 Analog FXO VoIP Gateway Public Internet or Private WAN
Configuring Local FXO Extensions Enterprise Network Analog FXO VoIP Gateway 192.168.1.123
Configuring Local FXO Routing Enterprise Network Analog FXO VoIP Gateway 192.168.1.123
Configuring Remote FXS Extensions Subscribers Analog FXS VoIP Gateway 192.168.1.202
Configuring Remote FXS Routing Subscribers Analog FXS VoIP Gateway 192.168.1.202
IP Network Remote Users connected via VoIP Subscribers Enterprise Network Subscribers maintain all feature functionality as local users on the PBX. Vega 50 Analog FXS VoIP Gateway Vega 50 Analog FXO VoIP Gateway Public Internet or Private WAN
IP Network Adding IP-Only Users Subscribers IP Phones Enterprise Network Vega 50 Analog FXS VoIP Gateway Vega 50 Analog FXO VoIP Gateway • An IP phone is simply a single-port VoIP media gateway
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?
Trunk Signaling Methods • In-Band Signaling • CAS – Channel Associated Signaling • R2 • E&M Wink Start • FGD Combined Voice and Signaling Channel • Out-of-Band Signaling • ISDN / Q.931 • SS7 D-Channel Bearer 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) Network Side User Side D-Channel PSTN Bearer Channel Clock Timing
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?
Remote VoIP Locations – PSTN Connectivity Subscribers Enterprise Network PSTN Public Switched Telephone Network Enterprise Network Subscribers
Remote VoIP Locations – Connecting Locations via PSTN Enterprise Network Network Side ISDN PRI User Side PSTN User Side ISDN PRI Enterprise Network
IP Network Remote VoIP Locations - Adding VoIP Enterprise Network PSTN Enterprise Network
IP Network Remote VoIP Locations – Adding VoIP Enterprise Network PSTN Enterprise Network
IP Network Remote VoIP Locations – Adding VoIP Gateways Enterprise Network Vega 400 PRI VoIP Gateway User Side PSTN ISDN PRI Network Side Network Side ISDN PRI User Side Vega 400 PRI VoIP Gateway Enterprise Network