Router-A# show running-configuration s0/0 interface serial0/0 description connected to router A IP address 10.10.10.1 255.0.0.0 encapsulation frame-relay shutdown clock rate 64000
Based on the interface configuration provided, which two statements are TRUE? (Choose two.)
- The router’s serial interface is connected using a DTE cable.
- The router’s serial interface is connected using a DCE cable.
- The router’s serial interface is administratively down.
- The router’s serial interface connects using the point-to-point protocol.
The command output shows that the router’s serial interface is connected to a DCE cable, and the router’s serial 0/0 interface is administratively down. The clock rate is only configured when a DCE cable is connected to the router. Use the clock rate interface configuration command to configure the clock rate for the WAN link on serial interfaces. This command is used to set the interfaces clock rate to match the circuit clock rate.
This will only be the case when a router is connected to another router with a back-to-back serial cable. Typically, a CSU/DSU acts as the DCE device and the router acts in a DTE role. The CSU/DSU terminates the digital local loop. In the case of an analog local loop, a modem would terminate the loop.
The command output proves that the router’s serial 0/0 interface is administratively down by the presence of the shutdown statement for the serial 0/0 interface.
The router’s serial interface does NOT connect to the CSU/DSU using a DTE cable. The clock rate statement would not be present when the serial interface is attached to a DTE cable.
The router’s serial interface does NOT connect using the point-to-point protocol. The router is using the frame relay Layer 2 protocol as indicated by the encapsulation frame-relay statement in the output.
DTE and DCE serial cables can also be used to connect routers to each other. When a router connects to a CSU/DSU, it must use a DTE cable to connect. When two routers are connected, the router that supplies the clocking should be connected to the DCE cable. The other router should be connected to the DTE cable. The two cables are then connected to each other.
Select the appropriate cabling type based on implementation requirements