Page "Client–server model" Paragraph 16

* As soon as the total number of simultaneous client requests made to a server increases, the server can become overloaded.

Contrast that to a P2P network, where its aggregated bandwidth actually increases as nodes are added, since the P2P network's overall bandwidth can be roughly computed as the sum of the bandwidths of every node in that network.

However, this simple model ends with the bandwidth of the network: Then congestion comes on the network and not with the peers.