What is the administrative distance (AD) for eBGP compared to other routing protocols?

The administrative distance (AD) for eBGP (External Border Gateway Protocol) is 20, which serves as a crucial metric for routers when determining the trustworthiness of routing updates from different protocols. Administrative distance is a value that routers use to prioritize routes from different sources. Lower values indicate higher trustworthiness.

In the context of routing protocols, eBGP is considered less reliable than IGP (Interior Gateway Protocol) routes like OSPF and EIGRP, which have lower AD values. The assignment of an AD of 20 for eBGP reflects its role in external routing, where the routes may not be as reliable as those originating from an internal network context.

This value helps routers make decisions about which routes to install in the routing table, especially when multiple protocols provide competing routes to the same destination. Understanding the administrative distance assigned to various routing protocols, including eBGP, is essential for troubleshooting and effectively managing routing behavior in network environments.