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Chapter 7 Troubleshooting the Cisco IP Phone
Resolving Startup Problems
7-22
Cisco IP Phone Administration Guide for Cisco CallManager 3.2, Cisco IP Phones 7960/7940/7910
78-10453-04
force a firmware upgrade from Cisco CallManager on to the phone. Anytime a
phone has to load a new image, it has to restart itself and re-register with
Cisco CallManager using the new image
However, if users report that their phones appear to be resetting during calls or
while idle on their desk, you should investigate the cause. If the network
connection and Cisco CallManager connection are stable, the Cisco IP Phone
should not reset on its own.
Typically, the cause of the phones resetting can be categorized by problems
connecting to the Ethernet network or to Cisco CallManager. These sections can
help you identify the cause in your network:
• Verifying Physical Connection, page 7-22
• Identifying Intermittent Network Outages, page 7-22
• Verifying DHCP Settings, page 7-23
• Checking Static IP Address Settings, page 7-23
• Verifying Voice VLAN Configuration, page 7-23
• Verifying that the Phones Have Not Been Intentionally Reset, page 7-23
• Eliminating DNS or Other Connectivity Errors, page 7-24
Verifying Physical Connection
Verify that the Ethernet connection to which the Cisco IP Phone is connected is
up-and-running. For example, check if the particular port or switch to which the
phone is connected is down.
Identifying Intermittent Network Outages
Intermittent network outages affect data and voice traffic differently. Your
network might have been experiencing intermittent outages without detection, but
data traffic can resend lost packets and verify 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.
Therefore, if you are experiencing problems with the voice network, you should
investigate whether an existing problem is simply being exposed at this point.