Moneropedia

Floodfill

The Basics

By actively managing a distributed network-database, a router with floodfill capability has the ability to help maintain network stability and resiliancy while also being decentralized and trust-less.

In-depth information

Though floodfill itself is a simple storage system, the technical underpinnings of floodfill as it relates to Network Database and other protocols within I2P are much more complex. Visit the Network Database page for details.