ZyXEL Communications P-2812HNU-51c User Manual page 236

Chapter 16 VoIP
The SIP proxy server forwards the call invitation to C.
2
Figure 110 SIP Proxy Server
A
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 to the IP address that it received back from the
redirect server. Redirect servers do not initiate SIP requests.
In the following example, you want to use client device A to call someone who is using client device
C.
Client device A sends a call invitation for C to the SIP redirect server B.
1
The SIP redirect server sends the invitation back to A with C's IP address (or domain name).
2
236
B
1
2
C
P-2812HNU(L)-Fx Series User's Guide