ZyXEL Communications prestige 2602h series User Manual

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Prestige 2602H/HW Series User’s Guide
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Chapter 8 Introduction to VoIP
Figure 53   SIP Proxy Server
8.2.3.3  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).
The SIP redirect server sends the invitation back to A with C’s IP address (or domain 
name).
Client device A then sends the call invitation to client device C.