Cracking of Wireless Networks - Wireless Network Basics

Wireless Network Basics

• Wireless local-area networks are based on IEEE 802.11. This is a set of standards defined by the Institute of Electrical and Electronics Engineers.
• 802.11 networks are either infrastructure networks or ad hoc networks. By default, people refer to infrastructure networks. Infrastructure networks are composed of one or more access points that coordinate the wireless traffic between the nodes and often connect the nodes to a wired network, acting as a bridge or a router.
  • Each access point constitutes a network that is named a basic service set or BSS. A BSS is identified by a BSSID, usually the MAC address of the access point.
  • Each access point is part of an extended service set or ESS, which is identified by an ESSID or SSID in short, usually a character string.
  • A basic service set consists of one access point and several wireless clients. An extended service set is a configuration with multiple access points and roaming capabilities for the clients. An independent basic service set or IBSS is the ad hoc configuration. This configuration allows wireless clients to connect to each other directly, without an access point as a central manager.
  • Access points broadcast a signal regularly to make the network known to clients. They relay traffic from one wireless client to another. Access points may determine which clients may connect, and when clients do, they are said to be associated with the access point. To obtain access to an access point, both the BSSID and the SSID are required.
• Ad hoc networks have no access point for central coordination. Each node connects in a peer-to-peer way. This configuration is an independent basic service set or IBSS. Ad hoc networks also have an SSID.