Power-Fail Recovery Procedure - AT&T SB67030 System Administrator Manual

AT&T SB67010 Gateway, SB67030 Deskset System Administrator's Guide

Power-fail Recovery Procedure

When AC power returns after a power failure, if a device is setup to use DHCP and the device cannot find a DHCP server on the
network, the device will assign itself an IP address. This is called a self-assigned link-local address and the IP address begins with
the number 169 (169.254.xxx.xxx).
After power returns, all devices in the system may power up simultaneously, depending on the power arrangement of your site.
As devices regain power, they request IP addresses. In a large installation, the DHCP server may take several minutes to respond
because there are so many other devices on the same network, producing many requests for IP addresses. Devices should revert
to proper IP addresses after the DHCP server resolves the request, but if a system device continues to use an IP address that
starts with 169, then it cannot communicate with other devices on the network.
Once power has resumed after a power failure, we recommend that each Deskset and Gateway be checked to confirm that each
has started up properly. If any of the System devices' screens report Sync Fail or Synchronizing for more than ten minutes,
refer to "Reintroducing a Deskset Into the System" on page 104 and "Reintroducing a Gateway Into the System" on page 106
for recovery methods from these states.
Common Troubleshooting Procedures 108