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3 sip redirect server, Figure 48 sip proxy server – ZyXEL Communications ADSL VoIP IAD with 802.11g Wireless 2602HW Series User Manual

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Prestige 2602HW Series User’s Guide

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Chapter 9 Introduction to VoIP

Figure 48 SIP Proxy Server

9.2.3.3 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.

1 Client device A sends a call invitation for C to the SIP redirect server (B).

2 The SIP redirect server sends the invitation back to A with C’s IP address (or domain

name).

3 Client device A then sends the call invitation to client device C.