Which routing protocol is associated with an administrative distance (AD) higher than OSPF?

The correct answer is that the routing protocol associated with an administrative distance (AD) higher than OSPF is IGRP.

OSPF (Open Shortest Path First) has an administrative distance of 110, which is a critical aspect to understand when comparing different routing protocols. Administrative distance is a value that routers use to select the best route when multiple routes to a destination exist, where a lower AD indicates a more preferred route.

IGRP (Interior Gateway Routing Protocol), on the other hand, has an administrative distance of 100. While this value is lower than OSPF's, the question is looking for a protocol with a higher AD. Other protocols like RIP (Routing Information Protocol) have a higher AD of 120, making it a more suitable option in terms of being higher than OSPF.

In this context, EIGRP (Enhanced Interior Gateway Routing Protocol) and IS-IS (Intermediate System to Intermediate System) also have lower ADs (90 for EIGRP and 115 for IS-IS), thus reinforcing that IGRP is indeed a valid answer regarding its higher administrative distance when compared to OSPF.

This distinction in AD values helps in understanding the preference that routers give to certain protocols