Which administrative distance (AD) is associated with IGRP?

IGRP, or Interior Gateway Routing Protocol, is a Cisco proprietary routing protocol designed for the efficient exchange of routing information within a single autonomous system. The administrative distance (AD) is a value used by routers to determine the trustworthiness of the source of a routing information. Lower values indicate more preferred routing sources.

The administrative distance of IGRP is set at 100, which means that routes learned through IGRP will be preferred over those learned from protocols with a higher AD, such as Routing Information Protocol (RIP), which has an AD of 120. However, IGRP is less preferred than Enhanced Interior Gateway Routing Protocol (EIGRP), which has an AD of 90, and OSPF, which has an AD of 110. This ranking of administrative distances plays a crucial role in route selection, ensuring that routers make efficient decisions based on the most reliable routing information available. The correct identification of IGRP’s administrative distance helps network professionals configure and troubleshoot routing protocols effectively.