Chapter 9
Troubleshooting and Maintenance
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
The following suggestions can help you 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 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
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:
•
•
OL-12641-01
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
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.
Cisco Unified IP Phone 7962G and 7942G Administration Guide for Cisco Unified Communications Manager 6.0
for more information.
for more information.
Cisco Unified IP Phone Resets Unexpectedly
"Network Configuration
for
9-7