The system software on a Cisco Catalyst 3750 series switch was corrupted during a failed upgrade, and now
the switch no longer passes the POST on restart. You want to use the Xmodem Protocol to recover the system
software.
To which of the following ports on the switch could you connect? (Select the best answer.)

A.
an Ethernet port in the management VLAN

B.
the auxiliary port

C.
the console port

D.
the highest numbered Ethernet port on the switch

E.
the lowest numbered Ethernet port on the switch

Explanation:
You should connect to the console port of a Cisco Catalyst 3750 series switch to use the Xmodem Protocol for
system software recovery. Xmodem is a simple, errorcorrecting transfer protocol that can be used to transfer
an IOS software image from a PC to Cisco switch or router through its console port. When the system software
image on a switch or router becomes corrupted, the system will fail the poweron self-test (POST) when it
reloads and it will typically halt in an administrative mode, which is commonly called readonly memory (ROM)
monitor (ROMmon) mode. You can identify this mode on a switch or router by the command prompt that is
displayed at the console: switch: on a switch and rommon1> on a router. When in ROMmon mode, a switch or
router will no longer forward packets and thus can no longer be reached through traditional inband
management methods, such as through a management virtual LAN (VLAN) or an active network interface.
Instead, you must use an outofband management method to access a switch or router in ROMmon mode. The
only outofband access method available on a Cisco 3750 series switch that supports Xmodem for system
software recovery is the console port.
On a Cisco router, you could use either the console port or the auxiliary (AUX) port for outofband access if the
router is in ROMmon mode. The AUX port on a Cisco router is typically capable of supporting most of the
features available on a console port. Cisco switches either do not have AUX ports or do not support certain
features, such as system recovery, on their AUX ports if they have them.

Cisco: Recovering Catalyst Fixed Configuration Switches from a Corrupted or Missing Image