SIP FAQ : SIP Functionality :
How do prepaid calling cards work in a SIP network?
2001-Jan-22 10:57pm islepchin@dynamicsoft.com, jdrosen@dynamicsoft.com
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SIP FAQ : SIP Functionality :
How do prepaid calling cards work in a SIP network? |
| Note that, in general, prepaid calling cards only make sense in an IP network if there is a special-purpose VoIP internet, calls traverse a IP-to-PSTN gateway or VoIP packets receive special treatment. The SIP requests are forced to traverse a stateful proxy or a back to back User Agent (B2BUA), which controls the Internet telephony gateway, router QOS function or firewall, depending on the architecture. When the time is used up, the B2BUA or gateway issues a BYE request to both parties, using the existing call ID. It also disables the gateway connection, turns off any special QOS treatment for the RTP packets or closes the firewall for that stream. This requires no additions to either caller or callee. Sending a BYE suffices only if at least one of the end systems can be trusted to actually terminate the call when a BYE is received.
2001-Jan-22 10:57pm islepchin@dynamicsoft.com, jdrosen@dynamicsoft.com | |
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| 2001-Jan-22 10:57pm |
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