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Cisco Unified IP Phone 8941 and 8945 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 M anager, 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.