Which command(s) will enable you to configure only serial interface 0 on a Cisco router?
A.
router>interface serial 0
B.
router#interface serial 0
C.
router(config)#interface serial 0
D.
router(config-if)#interface serial 0
Explanation:
You can use either the router(config)# interface serial 0 command or the router(config-if)# interface serial 0 command to configure serial interface 0 on the router.
To perform configuration changes on a single interface, you must either enter interface configuration mode for that interface, or simply execute the command to
enter configuration mode for another interface while still at the configuration prompt for the previous interface.
Router configuration mode (as indicated by the prompt router(config)#) allows global configuration of the router. This mode, also referred to as the global
configuration mode, must be entered as a precursor to entering the interface configuration mode for a specific interface. The sequence of commands and prompts
to arrive at this mode would be:
Router> enable (enters privileged mode)
Router#config t (enters global configuration mode, t is short for terminal)
Router(config)# interface serial 0 (enters interface configuration mode for the serial 0 interface)Router(config-if)#
At this point, any commands executed would be configuration changes limited to the serial 0 interface. For example, to place an address on the interface, enable the
interface, and save the configuration, the command series and prompts would be:
Router> enable
Router# config t
Router(config)# interface serial 0
Router(config-if)# ip address 192.168.20.1 255.255.255.0 (addresses the interface)
Router(config-if)# no shutdown (enables or “turns on” the interface)
Router(config-if)# exit (exits global configuration mode)
Router(config)# exit (exits privileged mode)
Router# copy running-config startup config (copies the changes to the configuration file on the router)
Alternately, you could enter interface configuration mode for one interface while still in configuration mode for another interface, as shown below. After entering the
interface serial 1 command, you will be editing serial 1 instead of serial 0.
Router(config)# interface serial 0
Router(config)#
Router(config)# interface serial 1
You should not use the command router> interface serial 0. User EXEC mode, as indicated by the prompt router>, provides limited access to a router and is the
initial mode you see after authenticating to the router. The subcommand interface serial 0 is not functional before you proceed to global configuration mode and
interface configuration mode for a specific interface.
You should not use the command router# interface serial 0. Privileged mode (as indicated by the prompt router#) must be traversed to get to global configuration
mode before you can execute the subcommand interface serial0. This subcommand is not functional while you are still in privileged mode.
Objective:
Infrastructure Maintenance
Sub-Objective:
Use Cisco IOS tools to troubleshoot and resolve problemshttps://search.cisco.com/search?query=Cisco%20IOS%20IP%20Routing%20BFD%20Configuration%20Guide&locale=enUS&tab=Cisco
https://www.cisco.com/c/en/us/obsolete/routers/cisco-1600-series-routers.html