I have a client that has nine sites in the West Indies, with six of them using SDSL connections and the remaining three connected via ADSL. All sites are equipped with an RB951G and two Yealink phones and they all have the same setup.
The local links are a little unstable and it is pretty frequent to suffer small (5 to 10 mins) interruptions in service, with both SDSL and ADSL
With the ADSL linked sites the local IP phones (Yealink) in some instances don't seem able to re-register : we have to delete their presence from the RB951G connection tracking table in order to enable proper registration
This re-registration issue affects both phones on a site, but rarely both at once i.e. one phone will fail to re-register while the other continues to operate perfectly
The common denominator here seems to be the ADSL
I'm not sure what to test to understand what is going on; I redirected packets from both phones to a remote Wireshark capture
and all I can gather is that, before deleting the connection, the blocked phone keeps sending unanswered registration requests
Any ideas ?