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Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)
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Chapter
Cisco Unified IP Phone Resets Unexpectedly
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 Setup Menu” section on page 4-4 for more information.
Verifying the 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 the same switch as the 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 2-2 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 Applications button on the phone and choosing
Administrator Settings > 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:
Procedure
Step 1 Use the Reset Settings menu to reset phone settings to their default values. See the “Resetting or
Restoring the Cisco Unified IP Phone” section on page 9-12 for details.
Step 2 Modify DHCP and IP settings:
a. Disable DHCP. See the “Network Setup Menu” section on page 4-4 for instructions.
b. Assign static IP values to the phone. See the “Network Setup Menu” section on page 4-4 for
instructions. Use the same default router setting used for other functioning Cisco Unified IP Phones.
c. Assign a TFTP server. See the “Network Setup Menu” section on page 4-4 for instructions. Use the
same TFTP server used for other functioning Cisco Unified IP Phones.
Step 3 On the Cisco Unified Communications Manager server, verify that the local host files have the correct
Cisco Unified Communications Manager server name mapped to the correct IP address.