Chapter 9 Voice
protocol. In the following figure, either A or B can act as a SIP user agent client to initiate a call. A and B can also both act as a SIP user agent to receive the call.
Figure 96 SIP User Agent
SIP Proxy Server
A SIP proxy server receives requests from clients and forwards them to another server.
In the following example, you want to use client device A to call someone who is using client device C.
1The client device (A in the figure) sends a call invitation to the SIP proxy server (B).
2The SIP proxy server forwards the call invitation to C.
Figure 97 SIP Proxy Server
SIP Redirect Server
A SIP redirect server accepts SIP requests, translates the destination address to an IP address and sends the translated IP address back to the device that sent the request. Then the client device that originally sent the request can send requests
| 219 |
|
|