7-9
Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.0 (SCCP), Cisco Unified IP Phones
OL-8151-01
Chapter 7 Troubleshooting the Cisco Unified IP Phone
Cisco Unified IP Phone Resets Unexpectedly
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 procedure can help you determine if the phone has been properly
configured to use DHCP:
1.
Verify that you have properly configured the phone to use DHCP. See the
“Modifying DHCP Settings” section on page 4-15
for details.
2.
Verify that the DHCP server has been set up properly.
3.
Verify the DHCP lease duration. Cisco recommends that you set it to 8 days.
Cisco Unified IP Phones send messages with request type 151 to renew their
DHCP address leases. If the DHCP server expects messages with request type
150, the lease will be denied, forcing the phone to restart and request a new
IP address from the DHCP server.
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
“Configuring IP Settings” section on page 4-20
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.
Summary of Contents for 7902G - Unified IP Phone VoIP
Page 4: ......
