In peer-to-peer networking, a supernode is any node that also serves as one of that network's relayers and proxy servers, handling data flow and connections for other users. This semi-distributed architecture allows data to be decentralized without requiring excessive overhead at every node. However, the increased workload of supernodes generally requires additional network bandwidth and CPU time.
Some peer-to-peer designs allow for the user to control whether their node is a supernode; others do not. For example, Skype by default is configured as a supernode, an issue that has caused controversy. Despite criticism, Skype has contended that supernodes on their network act only to maintain information about who is online at a given time, and are not used to route calls between users. Beginning with version 3.0, Skype allows users to avoid becoming a supernode by modifying the Windows Registry.