
Chapter 9 SIP
P-2302HWUDL-P1 Series User’s Guide
131
9.1.7.2 Use NAT
If you know the NAT router’s public IP address and SIP port number, you can use the
Use
NAT
feature to manually configure the ZyXEL Device to use a them in the SIP messages.
This eliminates the need for STUN or a SIP ALG.
You must also configure the NAT router to forward traffic with this port number to the ZyXEL Device.
9.1.7.3 STUN
STUN (Simple Traversal of User Datagram Protocol (UDP) through Network Address
Translators) allows the ZyXEL Device to find the presence and types of NAT routers and/or
firewalls between it and the public Internet. STUN also allows the ZyXEL Device to find the
public IP address that NAT assigned, so the ZyXEL Device can embed it in the SIP data
stream. STUN does not work with symmetric NAT routers or firewalls. See RFC 3489 for
details on STUN.
The following figure shows how STUN works.
1
The ZyXEL Device (A) sends SIP packets to the STUN server (B).
2
The STUN server (B) finds the public IP address and port number that the NAT router
used on the ZyXEL Device’s SIP packets and sends them to the ZyXEL Device.
3
The ZyXEL Device uses the public IP address and port number in the SIP packets that it
sends to the SIP server (C).
Figure 71
STUN
9.1.7.4 Outbound Proxy
Your VoIP service provider may host a SIP outbound proxy server to handle all of the ZyXEL
Device’s VoIP traffic. This allows the ZyXEL Device to work with any type of NAT router
and eliminates the need for STUN or a SIP ALG. Turn off a SIP ALG on a NAT router in front
of the ZyXEL Device to keep it from retranslating the IP address (since this is already handled
by the outbound proxy server).
9.1.8 Voice Coding
A codec (coder/decoder) codes analog voice signals into digital signals and decodes the digital
signals back into voice signals. The ZyXEL Device supports the following codecs.
•
G.711
is a Pulse Code Modulation (PCM) waveform codec. PCM measures analog signal
amplitudes at regular time intervals and converts them into bits. G.711 provides very good
sound quality but requires 64kbps of bandwidth.
Summary of Contents for Network Device P-2302
Page 2: ......
Page 8: ...Safety Warnings P 2302HWUDL P1 Series User s Guide 8 ...
Page 10: ...Contents Overview P 2302HWUDL P1 Series User s Guide 10 Appendices and Index 285 ...
Page 32: ...32 ...
Page 46: ...Chapter 2 Introducing the Web Configurator P 2302HWUDL P1 Series User s Guide 46 ...
Page 66: ...Chapter 3 Wizard Setup P 2302HWUDL P1 Series User s Guide 66 ...
Page 77: ...77 PART II Network Wireless LAN 79 WAN 95 LAN 105 NAT 117 ...
Page 78: ...78 ...
Page 94: ...Chapter 5 Wireless LAN P 2302HWUDL P1 Series User s Guide 94 ...
Page 116: ...Chapter 7 LAN P 2302HWUDL P1 Series User s Guide 116 ...
Page 125: ...125 PART III VoIP SIP 127 Phone 141 Phone Book 155 PSTN Line 159 VoIP Trunking 161 ...
Page 126: ...126 ...
Page 136: ...Chapter 9 SIP P 2302HWUDL P1 Series User s Guide 136 Figure 74 VoIP SIP SIP Settings Advanced ...
Page 154: ...Chapter 10 Phone P 2302HWUDL P1 Series User s Guide 154 ...
Page 176: ...Chapter 13 VoIP Trunking P 2302HWUDL P1 Series User s Guide 176 ...
Page 177: ...177 PART IV Security Firewall 179 Content Filter 187 ...
Page 178: ...178 ...
Page 186: ...Chapter 14 Firewall P 2302HWUDL P1 Series User s Guide 186 ...
Page 190: ...Chapter 15 Content Filter P 2302HWUDL P1 Series User s Guide 190 ...
Page 192: ...192 ...
Page 196: ...Chapter 16 Static Route P 2302HWUDL P1 Series User s Guide 196 ...
Page 228: ...Chapter 19 UPnP P 2302HWUDL P1 Series User s Guide 228 ...
Page 250: ...Chapter 21 File Sharing P 2302HWUDL P1 Series User s Guide 250 ...
Page 251: ...251 PART VI Maintanence and Troubleshooting System 253 Logs 261 Tools 273 Troubleshooting 279 ...
Page 252: ...252 ...
Page 260: ...Chapter 22 System P 2302HWUDL P1 Series User s Guide 260 ...
Page 272: ...Chapter 23 Logs P 2302HWUDL P1 Series User s Guide 272 ...
Page 278: ...Chapter 24 Tools P 2302HWUDL P1 Series User s Guide 278 ...
Page 286: ...286 ...
Page 292: ...Appendix A Product Specifications P 2302HWUDL P1 Series User s Guide 292 ...
Page 322: ...Appendix E SIP Passthrough P 2302HWUDL P1 Series User s Guide 322 ...
Page 346: ...Appendix H Legal Information P 2302HWUDL P1 Series User s Guide 346 ...