revision for peer to peer and client server

client server

lan  = local area network wan = wide area network one or more servers may be part of a local area network a server may also be a part of a wide area network google has massive servers in several different countries   every google search uses the same amount of energy as making a cup of tea example: a school network, there may be dozens or even hundreds of clients and several servers and backups a file server holds all the data files and databases and manages backups a print server may organise printing on different printers  an email server may receive emails, detect and block spam, distribute emails to users a web server may host in school the schools external website   role of a client on a client server a client sends their request to a server waits and receives the reply   server role waits for request from a client acknowledges the request it might be that the server needs to become the client the data then gets returned to the original client   features  central server is used o manage security some files re held on the central server some processing tasks are performed by the server  client issue requests to the server for services such as email, file storage, small and large can require specialist IT staff          

peer to peer

there is NO central server like client servers   features: suitable for a small or new business with fewer computers ore its a household no central server controls files or security all computers can communicate with each other without a server if a computer is turned off it is not accessible in anyway without being turned on   advantages of p2p easy to set up no special software or members of staff individual computers can share other devices and files directly   drawbacks viruses and malware easily transfer data recovery and retrieval is not done centrally  so users need to do it on their own files are not centrally is not kept together so if a user has not got any easy way of locating files it is hard to locate what users are after