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Full Version: incoming calls drop on two different phones
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Hi,
The following issue is happening for both a t41p and a t46g (which I bought after thinking the t41p might be faulty)

Outgoing calls always work without issue - but incoming calls on my phone will drop after 30 seconds.

I have worked extensively with my hosted PBX provider doing sip traces and neither of us can pinpoint the issue.

I have customers using the same hosted PBX with T41p and t46g phones and they work without issue (thank goodness). I also have a Cisco SPA303 on another desk and it never drops a call.

The router in our customers premise is a Cisco 867, and the router in our office is a Cisco 877.

I have switched of SIP ALG, and put a class-map to inspect(pass) SIP traffic going in and coming out.
I have setup a QOS policy for both RTP and SIP packets for high priority and that is registering the packets in the correct queue.

My PBX provider is saying that my phone is receiving the invite and responding okay, but then never receiving the ACK back from the PBX. The call is still connected however and I can speak for 30 seconds before my phone sends a sip BYE to the PBX and hangs up the call.
I also changed the sip NOTIFY UDP setting to 15 seconds, and that is being received.

Interestingly, if I force a re-registration from the phone - incoming calls will work for a while without dropping, but if I haven't received a call in a while it will drop. From that point on if I test it by calling from my mobile it drops everytime without fail.

Can anybody think of anything that might cause this very odd behaviour?

Thanks
Hi,

Have you tried upgrading T41/T46 to latest V73 firmware?
http://www.yealink.com/SupportDownloadfi...8&flag=142

Do you configure a STUN setting? What's your pbx server?
If new firmware don't work please send us the pcap trace, config.bin.

Regards,
James
(04-29-2015 06:13 PM)Yealink_James Wrote: [ -> ]Hi,

Have you tried upgrading T41/T46 to latest V73 firmware?
http://www.yealink.com/SupportDownloadfi...8&flag=142

Do you configure a STUN setting? What's your pbx server?
If new firmware don't work please send us the pcap trace, config.bin.

Regards,
James

Hi they are both running the latest firmware - issue persistent on both original and updated firmware.
There is no STUN server configured. The PBX server is asterisk.

I'll attach the pcap, syslog and config

Thanks for helping
Hi,
Problem has been solved.
The cisco router was set to inspect sip packets - and obviously they thought something was not RFC compliant - either with the Yealink or the asterisk PBX. Changing the class-map to inspect and pass all udp packets has solved the problem.

Thanks again for your assitance
Nice to hear that you solve the problem Smile.

Regards,
James
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