Client-server and peer-to-peer

Client-server	Peer-to-peer
One or more computers (clients) connected to a powerful central computer (server) \n \n Client makes request to server, which processes the request and sends a response	Individual computers connected to each other, either in a LAN or over a WAN so that they can share files and resources
Client may hold some of its own files and resources, but can also access resources held by the server	No central server - peers on the network can act as either client or server depending on which device is making the request
Large networks - may be several servers, with each server performing a different task	Below advantages are for small networks, e.g. a home or small office
}}Better security - files stored in central location, access rights managed by server}}	[[Worse security and may be file version conflicts if peers hold different copies of the same file[[
}}Backups done centrally - no need for individual users to back up their data}}	[[Backups done on individual devices, if at all \n (up to user) - makes it harder for data to be restored[[
}}Data and other resources can be shared}}	}}Enables users to share resources (printers, routers…)}}
[[Expensive to install and manage[[	}}Cheap to set up}}
[[Expertise required - professional IT staff needed for server maintenance and to run the network[[	}}Little-to-no expertise required and not difficult to maintain}}

Server type	Role
File	Holds and manages data for all clients
Print	Manages print requests
Web	Manages requests to access the Web
Mail	Manages the email system
Database	Manages database applications

P2P has been widely used for piracy, since files being illegally downloaded are very difficult to trace
2011: US Chamber of Commerce estimated piracy sites attracted 53bn visits / year
E.g. Napster

Less money for industries (e.g. music, movie, publishing, photography) to make more content
Loss of jobs