Topology of a wireless network—logical topology. Wireless network architecture depicts how computers communicate with one another when there is no physical link. Wireless devices are used by the computers to communicate with one another. The three main types of wireless networks are ad hoc, infrastructure, and hybrid. An ad hoc network is simply a group of computers that connect to each other without the help of an intermediate device. This type of network can be created quickly when needed and does not require any fixed infrastructure. It is useful for short-lived connections between multiple users at different locations. An example of an ad hoc network is a group of people who join together for a conference room party. They connect their laptops to each other so they can share files and play games over the internet. In an infrastructure network, computers are connected to a router, which is like a big switch for computers and other devices connected to them. The router handles routing tasks for the computers connected to it. For example, it can forward messages to other routers until they reach their destination. Internet providers use an infrastructure model when connecting groups of users together. One central router connects to other routers using long-distance cables while others close-up to individual users using local lines. A hybrid network combines features of both ad hoc and infrastructure networks.