Refer to the exhibit.
From this NFAS-enabled T1 PRI configuration on a Cisco IOS router, how many bearer channels are
available to carry voice traffic?
A.
91
B.
92
C.
93
D.
94
E.
95
Explanation:
A T1 circuit typically carries 24 individual timeslots. Each timeslot in turn carries a single telephone
call. When a T1 circuit is used to carry Primary Rate ISDN one of the timeslots is used to carry the D
channel. A single Primary Rate ISDN circuit is thus sometimes described as 23B + D. There are 23
bearer channels carrying voice or data, and one D channel carrying the Common Channel Signaling.
In this case, there are 96 total channels in the group, but only 1 will be needed for use as the D
channel, leaving 95 available for bearer channels.