Cisco Systems ATA187I1ARF Manual De Usuario

If users report that their phones are resetting during calls or while idle on their desk, you should 
investigate the cause. If the network connection and Cisco Unified Communications Manager 
connection are stable, a Cisco Unified IP Phone should not reset on its own.

Typically, a phone resets if it has problems connecting to the Ethernet network or to 
Cisco Unified Communications Manager. These sections can help you identify the cause of a phone 
resetting in your network:

Verify that the Ethernet connection to which the ATA 187 is connected is up. For example, check whether 
the particular port or switch to which the phone is connected is down and that the switch is not rebooting. 
Also make sure that there are no cable breaks.

Intermittent network outages affect data and voice traffic differently. Your network might have been 
experiencing intermittent outages without detection. If so, data traffic can resend lost packets and verify 
that packets are received and transmitted. However, voice traffic cannot recapture lost packets. Rather 
than retransmitting a lost network connection, the phone resets and attempts to reconnect its network 
connection.

If you are experiencing problems with the voice network, you should investigate whether an existing 
problem is simply being exposed. 

Follow this process to help determine if the phone has been properly configured to use DHCP:

Verify that you have properly configured the phone to use DHCP. See 

 for more information.

Verify that the DHCP server has been set up properly.

Verify the DHCP lease duration. Cisco recommends that you set it to 8 days.