VoIP Troubleshooting
If following symptoms happen on the ATA
Make sure you are using the supplied power adapter and that it is plugged in to an appropriate power source. Check that the power source is turned on. If the problem persists, you may have a hardware problem. In this case, you should contact your local vendor.
The supplied power to p2002 is too low. Check that the p2002 is receiving enough power the required power supplied to p2002 is 12VAC, 1Amp.
How can I check if problem is cause by NAT or not?
There may not be an easy or quick answer to this. One of the best way to see if the problem is cause by NAT or not is to put p2002 on public network, (With public IP and no NAT) see if it work under such condition.
If you it can work on public network but can not work behind NAT than very likely your NAT gateway is not supporting SIP pass-through. In such condition you will need to consult your NAT router vendor for resolution.
If I've confirmed it is not an NAT. What should I do?
If you are certain or confirmed the problem is cause by NAT you need to check the following.
1. Check if your NAT router vendor supports SIP pass-through.
2. If the NAT router does not support SIP pass-through, you need to consult your ITSP support if they support SIP outbound proxy. Since different NAT router vendor implement NAT differently. Typically ITSP may provide SIP outbound proxy to resolve NAT pass-through issues as sip proxy does not require the SIP client to do any modification as the server will modify the SIP message content according to the your WAN IP it sees. If your ITSP supports outbound proxy you need to obtain the configuration and configured the outbound proxy location on p2002.
3. As mentioned some NAT may not be SIP friendly. ITSP may support STUN instead of SIP outbound proxy to resolve this issue. To use STUN sip client must support STUN client. How STUN work is when the user register the server will tell SIP client what the WAN IP the server see from the SIP client and SIP client will use this IP as SIP content to identify it's location. p2002 does not support STUN client at this moment.
Unable to register with the SIP server?
If you are unable to register with SIP server.
1.Make sure the Internet is reachable and the SIP register server is reachable.
2.Make sure the SIP account are correct and the password are correct.
3.Check if there are NAT router before it. If there are NAT router before it follow troubleshooting step above to verify if NAT is the cause of the problem.
I can register but can not establish a call?
If you can register to server but can not make a call very likely there are NAT router before it, please see NAT related question above for tips to troubleshoot.
I can make a call but the voice only goes one way not bothway?
If you can register to server but can make a call signal establishment but the voice only goes one way very likely there are NAT router before it, please see NAT related question above to tips to troubleshoot.
I can receive a call but the voice only goes one way not bothway?
If you can register to server but can make a out going call but can not receive incoming calls or the incoming call signal establishment can be made but voice only goes oneway very likely there are NAT router before it, please see NAT related question above for tips to troubleshoot.
If all the about have been tried, but register still fail or call still have problem to be made behind the NAT what should I do?
In such case, please contact your local vendor for support. If they can't help out the problem they will escalate your problem to ZyXEL tech center. To report a problem please prepared below info.
1. Serial number of the device.
2. SIP Call server type and vendor.
3. Your device firmware version and romfile with password.
4. Detail information what you have tried to resolve the problem.
The support tells me, I may have an interoperabiltiy issue with my ITSP call server. Packet trace is requested by support to analyze the problem. Should I setup the environment and how do I trace the packet?
In such as you will need to setup your environment similar as scenario A & B to perform packet trace. Make a failed trace and make a successful trace by setting up scenario A & B and send it to support for problem analysis.
To perform packet trace the equipment required is as follow
1. PC installed with packet sniffer such as "Sniffer" or "Ethereal" to make the packet capture. Sniffer is a commerical software if you do not have it, you can use Ethereal which is a freeware and can be downloaded from www.ethereal.com to perform the packet capturing.
2. hub and Ethernet cable.
Scenario A
1. Connect the hub between the p2002 and the front end NAT router with Ethernet cable.
2. Connect the PC with packet sniffer installed to the hub.
3. Start packet sniffing software and start packet capturing.
4. Start p2002 and make a complete call from registering to calling a party until problem appear.
5. Stop capturing and save the captured packet in file.
Scenario B
1. Connect the hub between the p2002 and the front end CPE with Ethernet cable (Make sure p2002 is with public IP).
2. Connect the PC with packet sniffer installed to the hub.
3. Start packet sniffing software and start packet capturing.
4. Start p2002 and make a complete call from registering to calling a party.
5. Stop capturing once call is established and voice can transferred bothway successfully.
6. Save the captured packet in file.
Once both of the above capture is completed, send both captured file to support to analysis the cause.
All contents copyright (c) 2004 ZyXEL Communications Corporation.