Avaya IP Office

How the IP Office System Receives Time
The IP Office control unit contains a battery backed clock which is used to maintain system time during normal operation and when mains power is removed. The time is obtained using Time protocol (RFC868) requests. Note that this is different from Network Time Protocol (NTP). 

Following a reboot the IP Office control unit sends out a time request on its LAN1 interface. It first makes the request to the Voicemail Server IP address in its configuration and, if it receives no reply, then makes a broadcast request.