Massachussets Institute of Technology: Hari Balakrishnan's "Overlay Routing in the Internet"

As you read, try to answer the following question: how does the peer-to-peer model change or improve the client-server model discussed in the previous section?

Click http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-829-computer-networks-fall-2002/lecture-notes/L17overlay.pdf link to open resource.