Symptom: Cisco Unified Wireless Ip Phone Resets Unexpectedly; Verifying Access Point Settings; Identifying Intermittent Network Outages; Verifying Dhcp Settings - Cisco 7921G - Unified Wireless IP Phone VoIP Administration Manual

Resolving Voice Quality and Roaming Problems
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Symptom: Cisco Unified Wireless IP Phone Resets Unexpectedly

If users report that their phones are resetting during calls or resetting while idle on their desk, you should
investigate the cause. If the network connection and Cisco Unified Communications Manager
connection are stable, a Cisco Unified Wireless IP Phone 7921G should not reset on its own.
Typically, a phone resets if it has problems connecting to the access point and LAN or to
Cisco Unified Communications Manager. These sections can help you identify the cause of a phone
resetting in your network:
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Verifying Access Point Settings

Verify that the wireless configuration is correct. For example, check if the particular access point or
switch to which the phone is connected is down. See the
page 2-18

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. The
phone can retransmit and attempt to recover, or if the phone reaches the maximum retransmit rate, it
drops the packets or loses association with the access point.
If you are experiencing problems with the voice network, you should investigate whether an existing
problem is simply being exposed.

Verifying DHCP Settings

To determine if the phone has been properly configured to use DHCP, follow these steps:
Verify that you have properly configured the phone to use DHCP. See the
Step 1
section on page 5-6
Verify that the DHCP server has been set up properly.
Step 2
Verify the DHCP lease duration. Your local policy determines this setting.
Step 3
Cisco Unified Wireless IP Phone 7921G Administration Guide for Cisco Unified Communications Manager Release 7.0
10-8
Symptom: Improper Roaming and Voice Quality or Lost Connection, page 10-11
Monitoring the Voice Quality of Calls, page 10-12
Verifying Access Point Settings, page 10-8
Identifying Intermittent Network Outages, page 10-8
Verifying DHCP Settings, page 10-8
Verifying Voice VLAN Configuration, page 10-9
Verifying that the Phones Have Not Been Intentionally Reset, page 10-9
Eliminating DNS or Other Connectivity Errors, page 10-9
for information about access point settings.
for details.
Chapter 10 Troubleshooting the Cisco Unified Wireless IP Phone 7921G
"VoIP WLAN Configuration" section on
"Configuring DHCP Settings"
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