t28 phones lagged and unreachable after firmware upgrade

[bsutton]

OK, we have made a little progress.

As noted when running the yealink_T28.2.70.0.140.rom firmware we are still seeing the occasional handset becoming unregistered for 10 seconds.
With some sip debugging we tracked down the problem.

Basically asterisk sends out an 'OPTION' sip packet to do a qualify about every 2 minutes.
However asterisk also forces the phone to re-register every hour by sending out a 'REGISTER' sip packet.

It appears that if an OPTION packet is sent and then asterisk immediately sends out a REGISTER packet, before the handset has had a chance to reply to the above OPTION packet, then the phone will become un-reachable until the new registration completes.

I'm not certain if this is an asterisk bug or a handset bug.
I should note that the handset does send the 'OK' packet back in response to the OPTION packet just after the 'REGISTER' gets sent.

We are looking at changing the OPTION and REGISTRATION timeouts to prime no.s to stop the two overlapping.

Its clear that the above problem is not the same issue that we had with phones becoming unreachable and lagged when running the T28.2.71.0.165.rom. They would be come unreachable for 1-2 minutes not 10 seconds and we have never seen a 70.0.140 phone become lagged.

The weight of evidence is that there is a bug in the 71.0.165 version of the firmware that is causing lag which unltimately causes the phone to become unregistered.

Over the next week we will move some of the phones back to the 71.0.165 firmware to try and reproduce the problem in a controlled manner.