You are the administrator for a small VoIP network connected to an ITSP in the United States. Your supervisor
informs you that he is hearing a fast busy signal when he picks up the handset of his IP phone. You have
verified that no other users are experiencing this problem.
In which of the following fault domains should you begin troubleshooting? (Select the best answer.)
A.
the IP phone
B.
the cable connecting the IP phone to the switch
C.
the network switch that is connected to the IP phone
D.
the voice network’s router
Explanation:
Because only one user is experiencing the problem, you should begin troubleshooting the IP phone fault
domain. Fast busy signals can be caused by a codec mismatch between an IP phone and a Cisco voice
gateway. You can determine what codec your supervisor’s phone is using by pressing settings > Status > Call
Statistics on the IP phone keypad. The default audio codec on a Cisco voice gateway is the G.729 codec, which
is a high-complexity compressed codec that consumes bandwidth at a rate of 8 Kbps.
You would not begin the troubleshooting process by examining the cable connecting the IP phone to the switch.You might check the cable connecting the IP phone to the switch or the switch port to which the cable is
connected if the IP phone were a Power over Ethernet (PoE) device that was not receiving power from the
switch or if Cisco Unified Communications Manager (UCM) reported that the device is of an unknown type. You
might also check the network cable and switch port if the device were powered by a power supply but unable to
register and download a configuration.
It is not likely that you would begin troubleshooting the network switch or the voice network’s router in this
scenario, because only one user is affected by the problem. You might begin troubleshooting the problem at the
network switch if an entire department within an organization were reporting a problem. You might begin
troubleshooting at the voice router if more than one department or the entire organization were experiencing a
problem.https://www.cisco.com/c/en/us/support/collaboration-endpoints/unified-ip-phone-7900-series/productsmaintenance-guides-list.html