One or more computers (clients) connected to a powerful central computer (server)

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
(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

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