Cisco CP-7911G Administration Guide - Page 236

General Troubleshooting Tips

Page 236 highlights

General Troubleshooting Tips Chapter 9 Troubleshooting and Maintenance General Troubleshooting Tips 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. 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. 9-16 Cisco Unified IP Phone 7906G and 7911G for Cisco Unified Communications Manager 6.0 OL11954-01

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Chapter 9
Troubleshooting and Maintenance
General Troubleshooting Tips
9-16
Cisco Unified IP Phone 7906G and 7911G for Cisco Unified Communications Manager 6.0
OL11954-01
General Troubleshooting Tips
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
Explanation
Daisy-chaining IP phones.
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.
Poor quality when calling digital
cell phones using the G.729
protocol.
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 cause
IP phones to re-register.
Prolonged broadcast storms (lasting
several minutes) on the voice VLAN
cause the IP phones to re-register with
another Cisco Unified Communications
Manager server.