General Troubleshooting Tips - Cisco 7911G - IP Phone VoIP Administration Manual

General Troubleshooting Tips

General Troubleshooting Tips
Cisco Unified IP Phone 7906G and 7911G for Cisco Unified Communications Manager 6.0
9-16
This section provides troubleshooting information for some common issues that
might occur on the Cisco Unified IP Phone.
Table 9-2 provides general troubleshooting information for the Cisco Unified IP
Phone.
Table 9-2 Cisco Unified IP Phone Troubleshooting
Summary
Daisy-chaining IP phones.
Poor quality when calling digital
cell phones using the G.729
protocol.
Prolonged broadcast storms cause
IP phones to re-register.
Chapter 9 Troubleshooting and Maintenance
Explanation
Do not connect an IP phone to another IP
phone through the access port. Each IP
phone should directly connect to a switch
port. If you connect IP phones together in
a line (daisy-chaining), a problem with
one phone can affect all subsequent
phones in the line. Also, all phones on the
line share bandwidth.
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.
Prolonged broadcast storms (lasting
several minutes) on the voice VLAN
cause the IP phones to re-register with
another Cisco Unified Communications
Manager server.
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