Difficulty: Easy
Correct Answer: The route is inaccessible.
Explanation:
Introduction / Context:
RIP uses hop count as its metric. The protocol defines a maximum of 15 hops; anything beyond that is considered unreachable to prevent routing loops from persisting indefinitely.
Given Data / Assumptions:
Concept / Approach:
A metric of 16 in RIP is the protocol’s representation of infinity. It marks a destination as unreachable, often used in route poisoning to explicitly withdraw a route. This avoids transient loops by ensuring all routers quickly treat the network as down until a valid advertisement appears.
Step-by-Step Solution:
Observe metric 16 in debug output.Map 16 → “infinite” in RIP metric space.Interpret as an unreachable/poisoned route.Expect neighbors to remove or de-preference the route accordingly.
Verification / Alternative check:
Check the routing table (show ip route). You should not see a usable path for 172.16.10.0 from that source; if present, it may be via another neighbor at a metric between 1 and 15.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing RIP’s metric of 16 with a legitimate distance; it is a sentinel for infinity only in RIP.
Final Answer:
The route is inaccessible.
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