Cisco CCNA mock exam questions sample test – Question 388

.Which Cisco IOS command configures the clock rate to 64,000 bits per second on an interface?

A. clock-rate 64000
B. clock rate 64k
C. clock rate 64000
D. clockrate 64000

Explanation:
The clock rate 64000 command would configure the clock rate to 64,000 bits per second on an interface. The clock rate command is used to configure the clock rate for hardware
connections on serial interfaces. These interfaces can be network interface modules (NIMs) and interface processors. The syntax of this command is clock rate bps.
A serial connection between two routers that are connected with a v.35 serial cable requires a clock rate on the Data Communications Equipment (DCE) end of the cable, but not on
the Data Terminal Equipment (DTE) end. When the router is connected to a CSU/DSU for connection to the outside world, the DCE end will be the CSU/DSU. In a lab environment or
any situation where you have two routers connected with this type of serial cable, a clock rate must be set on the DCE end of the cable.
When troubleshooting a connection of this type between routers, the state of the clock rate (set or unset) can be determined by running the show controllers command on the DCE
end. The output will display as follows if the clock rate is NOT set:
Router#show controllers s0/0
Interface Serial0/0
Hardware is PowerQUICC MPC860
DTE V.35 clocks stopped
More output omitted
Notice the DTE V.35 clocks stopped line, which indicates no clock rate is set. Another clue that there is a Layer 2 problem is the output of the show ip interface S0/0 command,
executed on the same interface below:
Router# show ip interface s0/0
Serial0/0 is up, line protocol is down
Internet address is 192.168.1.2/24
Broadcast address is 255.255.255.255
Notice the Serial0/0 is up, line protocol is down line. Serial0/0 is up indicates that the physical connection is good, but line protocol is down indicates a problem with Layer 2 . If you
were troubleshooting from the bottom layer to the top, you would now check Layer 2, which would be the clock rate.
If you want to change a DCE interface to a DTE device, you should use the no clock rate command.
All the other options are incorrect because these commands are syntactically incorrect.
Objective:
WAN Technologies
Sub-Objective:
Describe WAN access connectivity options