Multiple Server Nodes, Semi-Centralised Architecture

A semi-centralised peer-to-peer architecture is one that contains at least one central point of control or focus. The purpose of these control nodes can range from maintaining a stricter control over the whole network, to simply acting as a central reference point for the remaining nodes.

 

There is no reason why more than one central nodes cannot exist within the network. This has advantages such as potentially increasing a P2P systems reliability by removing a potential single point of failure, or if the nodes happen to be physically quite spread out having multiple central nodes could help tackle any loss in Quality-of-Service.

 

Communication within such an architecture can be similar to the single centralised index server architecture, with the difference that the central nodes can also be connected together. This can mean that the control nodes can essentially pool their knowledge when it comes to issues such as node locations.

 

An issue with this architecture is of how the nodes connect to the server nodes. If they are only connected to one server node then this can become a potential failure point, however allowing all nodes to connect to all servers might limit the advantages this architecture can provide.

 

This type of architecture can also allow for a hybrid of other types of architectures. For example, the server nodes could make use of a direct communication architecture amongst themselves, but collectively act as a single server node within a semi-centralised architecture.