Cisco 7975G Software Manual page 253

Troubleshooting and Maintenance
Summary
Loopback condition
Peer to peer image distribution
fails.
Cisco VT Advantage/ Unified
Video Advantage (CVTA)
Phone call cannot be
established
Explanation
A loopback condition can occur when the following conditions are met:
• The SW Port Configuration option in the Network Configuration
menu on the phone is set to 10 Half(10-BaseT/half duplex).
• The phone receives power from an external power supply.
• The phone is powered down (the power supply is disconnected).
In this case, the switch port on the phone can become disabled and the
following message will appear in the switch console log:
HALF_DUX_COLLISION_EXCEED_THRESHOLD
To resolve this problem, re-enable the port from the switch.
If the peer to peer image distribution fails, the phone will default to using
the TFTP server to download firmware. Access the log messages stored on
the remote logging machine to help debug the peer to peer image distribution
feature.
These log messages are different than the log messages sent to the
Note
phone log.
If you are having problems getting CVTA to work, make sure that the PC
Port is enabled, and that CDP is enabled on the PC port.
The phone does not have a DHCP IP address, is unable to register to Cisco
Unified Communications Manager, and shows a Configuring IP or
Registering message.
Verify the following:
1 The Ethernet cable is attached.
2 The Cisco CallManager service is running on the Cisco Unified
Communications Manager server.
3 Both phones are registered to the same Cisco Unified Communications
Manager.
4 Audio server debug and capture logs are enabled for both phones. If
needed, enable Java debug.
Cisco Unified IP Phone 7975G, 7971G-GE, 7970G, 7965G, and 7945G Administration Guide for Cisco Unified
General Troubleshooting Information
Communications Manager 9.0 (SCCP and SIP)
233