Features Page 87 of 910
IP Line Description, Installation and Maintenance

Operating parameters

IP Peer calls
IP Peer calls survive the following failure types:
• TLAN subnet failures.
• Signaling Server platform failures/restarts.
When the Signaling Server reboots after the failure, all sessions are lost.
Therefore, when the local IP Phone or far-end telephone releases the call,
no RELEASE message is sent to the other party. The other party must go
on-hook to become idle.
• Call Server warm starts.
IP Peer calls do not survive the Call Server cold start; all virtual trunks are
idled as the Call Server comes back up after the cold start. In this case, the
local IP Phone must go on-hook to become idle.
IP/TDM calls
IP/TDM calls do not survive a Call Server cold start; all DSP channels are
closed as the Call Server comes back up after the cold start. In this case, the
local IP Phone must go on-hook to become idle.
Dialing state
Only established calls survive failures. All calls having the DIALING state
on the Call Server are released when an LTPS or signaling failure occurs that
causes an IP Phone to unregister.
Calls that are ringing are handled as follows:
• If the IP Phone originating the ringing call unregisters, the call is released
by the Call Server.
• If the IP Phone receiving the call unregisters, the call receives CFNA
treatment if possible.