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Cisco Unified IP Phone 7970G/7971G-GE Administration Guide for Cisco Unified Communications Manager 7.0
OL-15299-01
Chapter 9 Troubleshooting and Maintenance
Cisco Unified IP Phone Resets Unexpectedly
Verifying DHCP Settings
Follow this process to help determine if the phone has been properly configured to use DHCP:
1. Verify that you have properly configured the phone to use DHCP. See the “Network Configuration
Menu” section on page 4-5 for more information.
2. Verify that the DHCP server has been set up properly.
3. Verify the DHCP lease duration. Cisco recommends that you set it to 8 days.
Cisco Unified IP Phones send messages with request type 151 to renew their DHCP address leases.
If the DHCP server expects messages with request type 150, the lease will be denied, forcing the
phone to restart and request a new IP address from the DHCP server.
Checking Static IP Address Settings
If the phone has been assigned a static IP address, verify that you have entered the correct settings. See
the “Network Configuration Menu” section on page 4-5 for more information.
Verifying Voice VLAN Configuration
If the Cisco Unified IP Phone appears to reset during heavy network usage (for example, following
extensive web surfing on a computer connected to same switch as phone), it is likely that you do not have
a voice VLAN configured.
Isolating the phones on a separate auxiliary VLAN increases the quality of the voice traffic. See the
“Understanding How the Cisco Unified IP Phone Interacts with the VLAN” section on page 2-3 for
details.
Verifying that the Phones Have Not Been Intentionally Reset
If you are not the only administrator with access to Cisco Unified Communications Manager, you should
verify that no one else has intentionally reset the phones.
You can check whether a Cisco Unified IP Phone received a command from
Cisco Unified Communications Manager to reset by pressing the Settings button on the phone and
choosing Status > Network Statistics. If the phone was recently reset one of these messages appears:
• Reset-Reset—Phone closed due to receiving a Reset/Reset from Cisco Unified Communications
Manager Administration.
• Reset-Restart—Phone closed due to receiving a Reset/Restart from Cisco Unified Communications
Manager Administration.
Eliminating DNS or Other Connectivity Errors
If the phone continues to reset, follow these steps to eliminate DNS or other connectivity errors: