User manual ZYXEL P-2302HWL

[. . . ] P-2302HW/HWL-P1 Series 802. 11b/g Wireless VoIP Station Gateway User's Guide Version 3. 60 Edition 1 9/2006 P-2302HW/HWL-P1 Series User's Guide Copyright Copyright © 2006 by ZyXEL Communications Corporation. The contents of this publication may not be reproduced in any part or as a whole, transcribed, stored in a retrieval system, translated into any language, or transmitted in any form or by any means, electronic, mechanical, magnetic, optical, chemical, photocopying, manual, or otherwise, without the prior written permission of ZyXEL Communications Corporation. Published by ZyXEL Communications Corporation. All rights reserved. Disclaimer ZyXEL does not assume any liability arising out of the application or use of any products, or software described herein. [. . . ] When you use SIP to make a VoIP call, it originates at a client and terminates at a server. A SIP client could be a computer or a SIP phone. One device can act as both a SIP client and a SIP server. 136 Chapter 9 SIP P-2302HW/HWL-P1 Series User's Guide 9. 1. 5. 1 SIP User Agent A SIP user agent can make and receive VoIP telephone calls. This means that SIP can be used for peer-to-peer communications even though it is a client-server 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 71 SIP User Agent 9. 1. 5. 2 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. 1 The client device (A in the figure) sends a call invitation to the SIP proxy server (B). 2 The SIP proxy server forwards the call invitation to C. Figure 72 SIP Proxy Server Chapter 9 SIP 137 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. 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. Figure 73 SIP Redirect Server 9. 1. 5. 4 SIP Register Server A SIP 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. 6 RTP 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. 138 Chapter 9 SIP P-2302HW/HWL-P1 Series User's Guide 9. 1. 7 NAT and SIP The ZyXEL Device must register its public IP address with a SIP register server. If there is a NAT router between the ZyXEL Device and the SIP register server, the ZyXEL Device probably has a private IP address. The ZyXEL Device lists its IP address in the SIP message that it sends to the SIP register server. NAT does not translate this IP address in the SIP message. The SIP register server gets the ZyXEL Device's IP address from inside the SIP message and maps it to your SIP identity. If the ZyXEL Device has a private IP address listed in the SIP message, the SIP server cannot map it to your SIP identity. [. . . ] Microsoft Networks' messenger service uses this protocol. The Network Basic Input/Output System is used for communication between computers in a LAN. IKE IMAP4 IMAP4S IRC MSN Messenger NetBIOS UDP TCP TCP TCP/UDP TCP TCP/UDP TCP/UDP TCP/UDP TCP/UDP TCP TCP UDP 500 143 993 6667 1863 137 138 139 445 5190 144 2049 NEW-ICQ NEWS NFS An Internet chat program. Network File System - NFS is a client/ server distributed file service that provides transparent file sharing for network environments. Network News Transport Protocol is the delivery mechanism for the USENET newsgroup service. [. . . ]