Two offices are connected via one 10 Gigabit Ethernet link. What happens to the EIGRP neighborship if a link failure occurs?

Question

Options

• AEIGRP neighbors stay up because the link has not gone down
• BEIGRP neighbors drop and EIGRP begins the query process
• CEIGRP neighbors drop after the EIGRP timers expire
• DEIGRP neighbors drop immediately

• A
  1% (1)
• B
  1% (1)
• C
  4% (3)
• D
  93% (64)

Explanation

When two offices are connected by a single physical link and that link fails, the router's interface transitions to a 'down' state immediately at Layer 1/2. EIGRP monitors interface state directly; when an interface goes down, EIGRP instantly removes any neighbors reachable only through that interface without waiting for hello or hold timers to expire. This is the key distinction: if the physical link stays up but hellos stop arriving, EIGRP would wait for the hold timer (default 15s on LAN) before dropping the neighbor. But a hard link failure bypasses the timer entirely-EIGRP drops the neighbor immediately and then initiates the DUAL query process to find an alternate path. Because there is only one link here, no feasible successor exists, so EIGRP goes active on affected routes.

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