General Troubleshooting Tips - Cisco 7945G Administration Manual

General Troubleshooting Tips

Table 9-1
Problem
Factory Reset Deleted 802.1X Shared Secret
Phone cannot obtain a DHCP-assigned IP
address
Phone does not register with
Cisco Unified Communications Manager
Phone status display as "Configuring IP" or
"Registering"
Cannot access phone menus to verify
802.1X status
General Troubleshooting Tips
Table 9-2
Table 9-2
Summary
Daisy-chaining IP phones
Poor quality when calling
digital cell phones using the
G.729 protocol
Prolonged broadcast storms
cause IP phones to reset, or be
unable to make or answer a call
Cisco Unified IP Phone 7965G and 7945G Administration Guide for Cisco Unified Communications Manager 6.1(3)
9-10
Cisco Unified IP Phone Security Troubleshooting (continued)
provides general troubleshooting information for the Cisco Unified IP Phone.
Cisco Unified IP Phone Troubleshooting
Explanation
Daisy chaining (connecting an IP phone to another IP phone through
the access port) is not supported. Each IP phone should directly
connect to a switch port.
In Cisco Unified Communications Manager, you can configure the
network to use the G.729 protocol (the default is G.711). When using
G.729, calls between an IP phone and a digital cellular phone will
have poor voice quality. Use G.729 only when absolutely necessary.
A prolonged Layer 2 broadcast storm (lasting several minutes) on the
voice VLAN may cause IP phones to reset, lose an active call, or be
unable to initiate or answer a call. Phones may not come up until a
broadcast storm ends.
Chapter 9
Possible Cause
These errors typically indicate that the phone has
completed a factory reset (see the
Reset" section on page 9-15) while 802.1X was enabled.
A factory reset deletes the shared secret, which is
required for 802.1X authentication and network access.
To resolve this, you have two options:
Temporarily disable 802.1X authentication on the
•
switch.
• Temporarily move the phone to a network
environment that is not using 802.1X authentication.
Once the phone starts up normally in one of these
conditions, you can access the 802.1X configuration
menus and re-enter the shared secret (see the
Authentication and Status" section on page
Troubleshooting and Maintenance
"Performing a Factory
"802.1X
4-34).
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