Chapter 9
Troubleshooting and Maintenance
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Verifying Physical Connection
Verify that the Ethernet connection to which the Cisco Unified IP Phone 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.
Identifying Intermittent Network Outages
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.
Verifying DHCP Settings
Follow this process to help determine if the phone has been properly configured to use DHCP:
1.
2.
3.
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
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 2-2
details.
Cisco Unified IP Phone 7975G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP and SIP)
OL-15790-01
Verifying that the Phones Have Not Been Intentionally Reset, page 9-8
Eliminating DNS or Other Connectivity Errors, page 9-8
Checking Power Connection, page 9-8
Verify that you have properly configured the phone to use DHCP. See the
Menu" section on page 4-5
Verify that the DHCP server has been set up properly.
Verify the DHCP lease duration. Cisco recommends that you set it to 8 days.
"Network Configuration Menu" section on page 4-5
for more information.
for more information.
Cisco Unified IP Phone Resets Unexpectedly
"Network Configuration
for
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