Copyright Goodheart-Willcox Co., Inc. 456 Security Essentials network where a wireless central base station is mounted on a building so multiple clients connect to it. Captive Portal A captive portal is web page a user must view when connecting to a wireless net- work before broad access to the network is granted. Typically, a captive portal enables a user to connect to access points, but to do anything more, the user must open a browser and accept the terms of service. This allows the operator of the WLAN the ability to present its acceptable use policy (AUP). If you have ever used public Wi-Fi at a library, airport, or restaurant, you likely had to agree to an acceptable use policy before accessing web pages. Essentially, you were “held captive” and could not access the Internet until agreeing to terms. There are commercial and open-source prod- ucts available for creating captive portals. Wireless Router A wireless router is a device that has the same capabilities of an AP but also adds functionality to wireless connections to LANs or WANs. Wireless routers can serve as an access point, but an access point cannot function as a router. This is due to a router’s ability to transmit data packets across large networks, such as the Internet. Routers maintain tables of information such as the locations and identifying infor- mation of other routers. Wireless Connection Methods There are multiple wireless communication methods used for interoperability between devices. Each method has advantages and vulnerabilities. Examples of wire- less connection methods include the following. Cellular Cellular is a network technology that enables communication through mobile devices by using a system of stations and transceivers that make up a cellular network. A cellular network is a type of wireless network in which transmissions are distributed over groups of geographic areas. A cellular network transmits data from multiple transmitters called base stations. Each base station is allotted a portion of the overall bandwidth. The coverage provided by the base station is contained within a specified geographic area known as a cell. Figure 14-7 shows how cells are arranged to provide coverage. When a mobile user moves out of one cell, the base station performs a handoff to the next cell. Cellular Generations Terms such as 4G and LTE are often used when talking about cellular networks. The G stands for generation. Generational specifications are provided by the Inter- national Telecommunication Union (ITU). The original Internet connection was 2G. Most users today have a 4G or, depending on location, 5G connection. The 4G stan- dard required providers to offer certain speeds. Long-Term Evolution (LTE) is the path used to provide 4G speeds. The top wireless providers have standardized 4G as their communication standard. The latest generation of cellular connectivity is called 5G, the rollout of which has already begun in major cities around the world. 5G networks are expected to provide larger channels for data speed, lower latency to improve response time, and ability to connect significantly more devices at one time. 3.4 3.5