VoIP Case Studies

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VoIP Case Studies

• Duncan MacAuslan
• Task Coordinator - VoIP
• ITP Training 2006
• 14 September 2006

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IP Layered Model
Service Provider
End user purchased applications, VSP
- theoretically there is no session layer in
the IP model, split here for clarity.
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Three carrier models
PBX
PBX
PSTN
Where we are now! Transitionary mixture
Traditional PSTN
PBX
PBX
IP WAN
Router/GW
Router/GW
PSTN core replaced by packet switching
Soft-Switch
Soft-Switch
IP WAN
Router
Router
Application Servers
Full end to end IP network the NGN
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VoIP Models

• Peer to peer
• Conventional
• Message
• Phone out from IP to PSTN
• Phone in from PSTN to IP
• DID
• Extension

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Connecting a traditional phone to VoIP
Phone/USB dongle
ADSL or cable
Internet
ATAs
Broadband Wireless
ATA analogue telephone adaptor
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IP handset connections
Connected to PC by sound card, USB or ethernet
ADSL or Cable to Internet
Internet
IP phones connected directly to local ethernet
Broadband Wireless
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Analogue Telephone Adaptor
PSTN used when no connection to internet
PSTN
LAN
Internet
Router
VoIP pathway
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VoIP calls to users on same VSP network
Internet
Fred calls VoIP user Jill
Call is routed across VSPs network to internet
gateway closest to Jill
Routed across internet to VSPs network
VSPs softswitch refers call to SIP server URI to
find Jills current IP address. SIP server then
drops out.
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Outbound one-way VoIP service
SIP used to map callers IP address and URI to
gateway phone number
Internet
PSTN
If gateway in Australia caller usually has
nominated a local call zone. If gateway overseas
caller must dial full e.164 code eg 61 2 9555
1234 even if called party is next door.
The gateway could be anywhere in the world
depending on best tariffs. If gateway overseas,
000, if allowed, will arrive on international
trunk CLI will be that of a line on gateway, if
overseas eg 1 123 555 555, not necessarily
identifying caller.
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Inbound PSTN to VoIP DID model
PSTN
Internet
Calling party dials VoIP user using PSTN number
routed across PSTN to VSPs incoming gateway
VoIP user is allocated PSTN number eg 02 95551234

VSPs softswitch refers call to SIP server to map
PSTN to URI and current IP address. SIP server
drops out.
Call is routed across gateway to internet
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Inbound PSTN to VoIP extension model
PSTN
Internet
Caller dials VSPs gateway using PSTN number 9555
1234
VoIP user allocated a extension eg 09137637
Routed across PSTN to VSPs incoming gateway.
When call established caller dials extension
52341 using DTMF
VSPs softswitch refers call to SIP server to map
extension to URI and current IP address. SIP
server drops out.
Call is routed across gateway to internet
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VoIP to VoIP
eg Skype
Internet
VSP2
VSP1
Phone out
Phone in
PSTN
Red line where VSP1 user must use PSTN to call
VSP2 user
Green line shows how a Skype user calls a VSP2
user
Purple shows how peering will avoid the PSTN
the NGN solution
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Some IP telephony examples

• Operator 1
• targeted at any broadband customer nationally
• launched early 2005
• new broadband churn processes,
• power supply notice to users,
• number allocation

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Operator 2

• Wireless broadband voice Sydney and Melbourne
  metro coverage
• Assessed numbering options, expected geographic
  but longer term will explore mobility capability,
  
• radio links should create greater customer
  awareness of power issue
• Endorsed third party VoIP provider over own
  network

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Operator 3

• Existing experience with customers and billing in
  cellular market
• Mass market (retail outlets and advertising) via
  any broadband link includes CE (process B)
• FAQs include a number of quality and performance
  warnings,
• numbers via 3rd party
• ISDN aspiring to CCS7

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Operator 4

• Triple play over cable with voice broadband and
  Pay TV
• Regional Victorian focus
• Agreed CE and customer advice warnings re
• power,
• temporary exemption from portability because of
  interface,
• highly localised pricing attraction