College student here with questions about implementation.

The Gnutella protocol does not specify how a client is to connect to the gnutella network in the first place. I have read that indexing servers are currently the most common method. I know about router.limewire.com:6346 and connect1.gnutellanet.com:6346. My question is: How do these work? Do they just track nodes that are known to be online or do they actually attempt to control the shape of the network by adding nodes to different parts of it? Is there anywhere I can go to read on this subject?

Thanks