11-30-2010 08:12 AM
I have a simple VoiP configuration using SPA9K, SPA400, SPA921 phones. I am trying to add a TEO TSG-6 phone into the configuration. The TSG-6 registers correctly however when I try to initiate a call to a local extension the receiving phone set never connects, only shows answering until it times out. Phone calls between SPA921 and SPA921 work correctly. Calls initiated from SPA921 to TSG-6 work correctly. Only calls initiated by the TSG-6 don't seem to work properly. Does anyone have any explanation?
12-04-2010 03:40 AM
Can you capture the traffic between two phones with wireshark?
You can do it configuring a span port on your switch.
Post also phones configuration.
Thanks.
12-06-2010 10:45 AM
I have run wireshark and what appears is between the SPA921 and TSG-6 phone the ACK is :
No. Time Source Destination Protocol Info
49 11.015128 193.104.0.53 193.104.0.52 SIP Request: ACK sip:1002@193.104.0.52:5060;transport=udp
This works correctly the phones connect and converstation is possible.
When I try between TSG-6 to TSG-6 or SPA921 the ack is:
No. Time Source Destination Protocol Info
11 3.080554 193.104.0.51 193.104.0.41 SIP Request: ACK sip:1002@193.104.0.52:5060;transport=udp
It appears the TSG-6 phone is expecting the ACK to come from the SPA9000 (193.104.0.41) instead of the other TSG-6 (193-104.0.52). The connection never completes. I have not found any setting in the SPA9000 where it could respond to the ACK as a proxy. Does anyone know of any other setting that may have an impact?
No. Time Source Destination Protocol Info
11 3.080554 193.104.0.51 193.104.0.41 SIP Request: ACK sip:1002@193.104.0.52:5060;transport=udp
It appears the TSG-6 phone is expecting the ACK to come from the SPA9000 (193.104.0.41) instead of the other TSG-6 (193-104.0.52). The connection never completes. I have not found any setting in the SPA9000 where it could respond to the ACK as a proxy. Does anyone know of any other setting that may have an impact?
12-06-2010 11:06 AM
I think that the problem is in your TGS-6 configuration. Can you post it?
Do you have configured Outbound Proxy?
12-07-2010 05:26 AM
TSG6 settings as follows:
SIP tab:
Proxy id - 192.168.0.1
Proxy udp port - 6060
Registrar enable on
Registrar id 192.168.0.1
Registrar port 6060
Registrar expiration 3600 seconds
Backup proxy id
Backup proxy port 5060
Backup registrar enable off
Backup registrar id
Backup registrar port 5060
Backup registrar expiration 3600 seconds
Outbound proxy
Outbound port 5060
Port 5060
RTP port 16392
RTP packet rate 10 milliseconds
Subscription expiration 3600 seconds
SIP call settings
Session timer unsupported
Session timer interval minimum 120 seconds
Session timer interval 3600 seconds
session refresher ANY
User Agent TEO
Call deflect id ALU_CALL_DEFLECTION
Loc call fwd id
Loc call fwd option off
Loc call fwd no-anwer time 12 seconds
emergency number
Hot-warm line number LU-FS5000-HOT_WARM
Phone context
Endpoint mode Normal
BusyLamp console base 0
Max rph r priority 2 (0-9)
Server type GENERIC
Session method is update OFF
Silence Supression OFF
Compact Headers OFF
Early Media detection ON
Message summary Subscription OFF
Prack Unsupported
Preconditions Unsupported
Privacy Values none
Resource Priority tag unsupported
Transport UDP
trys before using backup 8 times
Url Type SIP
line mode Normal
Dial plan
I have tried removing the Proxy id/leaving it blank but the phone won't register with the SPA9000.
12-07-2010 09:53 AM
I need more info.
Can you post both full wireshark traces?
Thanks.
12-08-2010 11:18 AM
12-08-2010 12:39 PM
Strange issue.
In your working scenario, the SPA921 receive a 200 message forwarded by SPA9000. This message contains the ip address of TEO phone in the contact field. The SPA921 should send an ACK to proxy (SPA9000) but it sends the ACK direct to TEO. This is not correct.
The RTP flow starts correctly but in closing phase, when TEO sends a BYE to the proxy (SPA9000) receives a 404 error message because SPA9000 doesn't know that the call started.
Correct scenario:
In your not working scenario the flow of sip messages is correct.
It seems that the problem is in the proxy (SPA9000). It receives the ACK message from TEO but doesn't forward it to the other phone.
Can you try your TEO phones with other proxy? I think that they will work properly.
Can you post your SPA9000 config?
12-09-2010 04:10 AM
The attached zip file contains screen captures from the SPA9000. Yes, I agree that the problem is the ACK is not being forwarded by SPA9000, I have not found any setting on the SPA9000 that seems to affect/change the problem. The SPA921 works because it send the ACK directly back to the TEO. The TEO dont work because they are expecting the SPA9000 to forward the ACK but it doesn't.
12-09-2010 12:05 PM
Try to enable PRACK on all equipments.
In SPA devices you can enable 100rel PRACK support under EXT -> SIP Settings -> SIP 100REL Enable menu.
In TEO phones change the option "Prack Unsupported".
After these changes re-capture the traffic with wireshark. This is not a workaround but I think that Provisional Response ACK modifies the behavior of devices.
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