Gateway Servers in VoIP Networks
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8/27/2008
Voice over IP (VoIP) and analog phones use different signaling and media transport mechanisms; therefore, they cannot interact directly.
To enable VoIP phones to interact with phones on the PSTN, many VoIP networks include gateways that provide functionality to link the two disparate networks.
A VoIP/PSTN gateway accepts SIP requests from VoIP phones and translates these requests to PSTN signaling. The gateway also translates media transport data from RTP to formats suitable for the PSTN. Likewise, the gateway accepts requests from the PSTN and maps them to VoIP phones on the IP network by generating the appropriate SIP and RTP data.
For more information about an example VoIP network that includes a PSTN gateway, see VoIP Phone Networks.