CompTIA Network+ Practice Test 2025 - Free Network+ Practice Questions and Exam Prep Guide

The routing protocol commonly referred to as the "three-napkins protocol" is Border Gateway Protocol (BGP). This nickname stems from the complex nature of its setup and configuration, which is often humorously described as requiring a lot of informal documentation or notation, akin to scribbles on napkins. BGP is fundamental for routing between different autonomous systems on the internet and is known for its capability to manage large amounts of routing information while ensuring stability and scalability.

In contrast, the other protocols mentioned focus on different aspects of routing. OSPF (Open Shortest Path First) is an internal link-state routing protocol that uses a more structured database to maintain routing information. EIGRP (Enhanced Interior Gateway Routing Protocol) is a hybrid protocol that supports multiple network layer protocols and relies on a combination of distance vector and link-state methodologies. RIP (Routing Information Protocol) is a simpler distance vector protocol, primarily used in smaller networks or for learning purposes. These other protocols do not bear the same informal and simplistic naming convention as BGP when it comes to their documentation or setup.