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If users report that their phones are resetting during calls or while the phones are idle, you should investigate the cause. If the network connection and Cisco Unified Communications Manager (Unified CM) connection are stable, a phone should not reset.

Typically, a phone resets if it has problems in connecting to the network or to Cisco Unified CM.

Problem

Your network may be experiencing intermittent outages.

Solution

Intermittent network outages affect data and voice traffic differently. Your network might be 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 to the network. Contact the system administrator for information on known problems in the voice network.

Problem

The DHCP settings may be incorrect.

Solution

Verify that you have properly configured the phone to use DHCP. Verify that the DHCP server is set up properly. Verify the DHCP lease duration. We recommend that you set the lease duration to 8 days.

Problem

The static IP address assigned to the phone may be incorrect.

Solution

If the phone is assigned a static IP address, verify that you have entered the correct settings.

Problem

If the phone appears to reset during heavy network usage, it is likely that you do not have a voice VLAN configured.

Solution

Isolating the phones on a separate auxiliary VLAN increases the quality of the voice traffic.

Problem

If you are not the only administrator with access to Cisco Unified Communications Manager (Unified CM), you should verify that no one else has intentionally reset the phones.

Solution

You can check if a wireless phone received a command from Cisco Unified CM to reset by accessing the Settings app on the phone and choosing Admin settings > Status > WLAN statistics.

• If the Restart Cause field displays Reset-Reset, the phone receives a Reset/Reset from Cisco Unified Communications Manager Administration.

• If the Restart Cause field displays Reset-Restart, the phone closed because it received a Reset/Restart from Cisco Unified Communications Manager Administration.

Problem

The phone reset continues and you suspect DNS or other connectivity issues.

Solution

If the phone continues to reset, eliminate DNS or other connectivity errors by following the procedure in Determine DNS or connectivity issues.