A router learns the exact same prefix 192.168.20.0/24 from three sources at once: RIP, OSPF, and internal EIGRP. With default settings and no manual configuration changes, which route is installed in the routing table?
- AThe internal EIGRP route, because its administrative distance of 90 is the lowest of the three Correct
- BThe OSPF route, because OSPF uses cost based on bandwidth and is more accurate than EIGRP
- CThe RIP route, because RIP hop count gives the simplest and most reliable loop-free path
- DAll three routes, because the router load-balances equally across every protocol that offers the prefix
Why A is correct: When the prefix is identical, the router trusts the source with the lowest administrative distance; internal EIGRP at 90 beats OSPF at 110 and RIP at 120, so the EIGRP route is installed.
Why B is wrong: Metric quality is irrelevant across different protocols; selection here is by administrative distance, and OSPF at 110 is higher than internal EIGRP at 90, so OSPF is not preferred.
Why C is wrong: RIP carries the highest administrative distance of these three at 120, so it is the least trusted; its hop-count metric is never compared against the other protocols' metrics.
Why D is wrong: Routers do not load-balance across different protocols for one prefix; equal-cost load balancing only happens within a single protocol, so only the lowest-AD source is installed.