Cisco Certified Network Associate (CCNA) Practice Exam

Which command is used to display clock rate and DTE/DCE status?

1. show vtp status

2. show controllers INTERFACE

3. show running-config

4. show spanning-tree vlan VLAN NUMBER

The correct answer is: show controllers INTERFACE

The command that displays clock rate and DTE/DCE status is indeed "show controllers INTERFACE." This command is specifically used on Cisco devices to provide detailed information about the physical characteristics of a given interface, particularly serial interfaces. When executed, the "show controllers" command reveals critical details such as the type of interface (whether it's DTE or DCE), the assigned clock rate, and other relevant settings that are essential for proper network configuration and troubleshooting. The DTE (Data Terminal Equipment) is typically where the clock rate is set, while the DCE (Data Circuit-terminating Equipment) receives the clock rate. In contrast, the other commands listed serve different purposes; for example, "show vtp status" provides information regarding the VLAN Trunking Protocol (VTP) and does not relate to clock settings or DTE/DCE status. The "show running-config" command displays the current configuration of the device, which may include interface configurations but does not specifically show clock rate or DTE/DCE information. Finally, "show spanning-tree vlan VLAN NUMBER" focuses on the spanning tree protocol status for a specified VLAN and is unrelated to the clock rate or interface controller details.