P-2302HW/HWL-P1 Series User’s Guide

9.1.5.3 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.

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

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

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

Figure 73 SIP Redirect Server

9.1.5.4 SIP Register Server

ASIP register server maintains a database of SIP identity-to-IP address (or domain name) mapping. The register server checks your user name and password when you register.

9.1.6RTP

When you make a VoIP call using SIP, the RTP (Real time Transport Protocol) is used to handle voice data transfer. See RFC 1889 for details on RTP.

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Chapter 9 SIP