While working in the core network building, a technician accidently bumps the fiber connection between two core switches and damages one of the pairs of fiber. As
designed, the link was placed into a non-forwarding state due to a fault with UDLD. After the damaged cable was replaced, the link did not recover. What solution
allows the network switch to automatically recover from such an issue?

A.
macros

B.
errdisable autorecovery

C.
IP Event Dampening

D.
command aliases

E.
Bidirectional Forwarding Detection

Explanation:
There are a number of events which can disable a link on a Catalyst switch, such as the detection of a loopback, UDLD failure, or a broadcast storm. By default,
manual intervention by an administrator is necessary to restore the interface to working order; this can be done by issuing shutdown followed by no shutdown on the
interface. The idea behind requiring administrative action is so that a human engineer can intercede, assess, and (ideally) correct the issue. However, some
configurations may be prone to accidental violations, and a steady recurrence of these can amount to a huge time sink for the administrative staff. This is where
errdisable autorecovery can be of great assistance. We can configure the switch to

automatically re-enable any error-disabled interfaces after a specified timeout period. This gives the offending issue a chance to be cleared by the user (for
example, by removing an unapproved device) without the need for administrative intervention.
http://packetlife.net/blog/2009/sep/14/errdisable-autorecovery/