Cisco 7975G Software Manual page 180

General Troubleshooting Tips
Table 9-2
Summary
Gaps in voice calls
Loopback condition
One-way audio
Peer Firmware Sharing fails.
Cisco VT Advantage/Unified
Video Advantage (CVTA)
Cisco Unified IP Phone 7975G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP and SIP)
9-12
Cisco Unified IP Phone Troubleshooting (continued)
Explanation
Check the AvgJtr and the MaxJtr statistics. A large variance
between these statistics might indicate a problem with jitter on the
network or periodic high rates of network activity.
See the
information about displaying these statistics.
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.
When at least one person in a call does not receive audio, IP
connectivity between phones is not established. Check the
configurations in routers and switches to ensure that IP connectivity
is properly configures.
If the Peer Firmware Sharing 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
Firmware Sharing feature.
Note
If you are having problems getting CVTA to work, make sure that
the PC Port is enabled, and that CDP is on the PC port.
See Network Configuration Menu, page 4-5
Chapter 9
"Call Statistics Screen" section on page 7-13
These log messages are different than the log messages sent
to the phone log.
Troubleshooting and Maintenance
for
for more information.
OL-15790-01