The popularity of peer-to-peer search networks continues to grow, even
as the limitations to the scalability of existing systems become
apparent. We propose a simple model for search networks, called the
search/index links (SIL) model. The SIL model describes existing
networks while also yielding organizations not previously
studied. Using analytical and simulation results, we argue that one
new organization, parallel search clusters, is superior to existing
supernode networks in many cases.