Cisco Certified Network Professional 2025 Complete Practice Test

The command that shows information related to unknown next-hop delays is "show ip cef adjacency glean." This command provides insights into the CEF (Cisco Express Forwarding) table, specifically detailing adjacency information for IP packets. When retrieving this data, the command reveals glean adjacency entries, which are associated with unknown next-hop delays.

In CEF, a glean adjacency occurs when the router does not have an explicit next-hop route in its forwarding table for a packet whose destination it knows. This often happens when the router is trying to forward packets to destinations that are not fully resolved, and it needs to handle these unknown next-hop situations, which can include delays or longer processing times while the routing information is updated.

Having this information is crucial for network troubleshooting and performance optimization, as it helps in identifying potential delays in packet processing due to unresolved paths. None of the other commands focus specifically on this type of adjacency or the delays associated with unknown next hops. For instance, the pending command is more about routes that are waiting to be installed or updated but does not specifically relate to unknown next-hop delays. The route summary and ARP table commands provide different types of networking information that do not directly address the issue of unknown next-hop delays.