I have 2 Asterisk servers (Primary and Secondary). The secondary runs a backup once a day to mirror the config of the primary.
All of our IP500’s are programmed to register to both servers and flawlessly fail over to the secondary if there is a problem.
I am now starting to experiment with SIP clients on Android and iPhone however these only support single server registration.
My problem is that if the primary goes offline the mobile phone does not know about the existence of the secondary. I have experimented with DNS-SRV which works fine however I have found that the following scenario causes problems:
Android registered to primary - Makes and receives calls via primary fine.
Primary goes offline so Android uses DNS-SRV to switch across to the secondary - Makes and receives calls via secondary fine
Primary comes back online however Android does not switch registration back therefore the IP500 handsets which are now back to the primary see the Android as being unreachable and cannot call the phone however the Android can make calls via the secondary.
Can anyone advise?