WLANs WPANs

Security Policies One of the first steps in providing wireless network security is to formulate effective policies and corresponding enforcement processes. Carefully analyze security requirements and invoke an adequate level of protection. For example, encryption should be part of all wireless ... [full story]

Authentication The use of mutual authentication is important in a wireless network. This will guard against many security issues, such as man-in-the-middle attacks. With mutual authentication, the wireless client and the wireless network must prove their identity to each other. This ... [full story]

Encryption Encryption alters the bits of each data packet to guard eavesdroppers from decoding data, such as credit card numbers. Before encryption the data is called plaintext, which is easy to decode by using sniffing tools. The encryption converts the plaintext ... [full story]

Security Threats As show in Figure 8-1, there are several forms of security threats to wireless networks. For example, hackers can steal information from a company, obtain unauthorized access to applications, and even disrupt operation of the network. Figure 8-1. Threats to ... [full story]

Wireless WAN Technologies Wireless WANs make use of technologies that focus on modulation of voice and data. As discussed in Chapter 2, "Wireless System Architecture: How Wireless Works," modulation converts digital signals that represent information inside a computer into either RF ... [full story]

Wireless WAN Systems Most wireless WANs are cellular based, but some make use of space. Take a closer look at both of these. Cellular-Based Wireless WANs As shown in Figure 7-6, a cellular system consists of cell towers, concentrators, voice switches, and data ... [full story]

Wireless WAN Components Wireless WANs satisfy both mobile and stationary applications. Components, therefore, vary depending on the technology and configuration of the wireless WAN. A satellite-based wireless WAN, for example, has different components than a cellular-based system. Wireless WAN User Devices Users of ... [full story]

Wireless MAN Technologies Many of the wireless MAN installations utilize proprietary technologies operating in licensed bands. The licensing avoids potential RF interference by ensuring that nearby systems are using different frequencies. Even though end users follow a process of obtaining a ... [full story]

Wireless MAN Systems Wireless MANs offer connections between buildings and users within a city or campus area through several system configurations. In most cases, the wireless MAN beams RF or infrared light from one point to another using directive antennae. Point-to-Point Systems A ... [full story]

Wireless MAN Components Components of a wireless MAN generally come in matching pairs because they support fixed wireless connectivity from one point to another. Take a look at the primary components of a wireless MAN. Bridges The industry definition of a bridge is ... [full story]

Wireless LAN Technologies 802.11 and HiperLAN/2 are the most common standards for wireless LANs. Examine each of these standards. 802.11 The IEEE 802.11 standard specifies a common medium access control (MAC) and several physical layers for wireless LANs. The initial 802.11 standard became ... [full story]

Wireless LAN Systems A wireless LAN system consists of a set of components and configurations that satisfy the needs of a particular application. It's possible to define a general wireless LAN system based on broad application types. Take a look at ... [full story]

Wireless LAN Components Wireless LANs consist of components similar to traditional Ethernet-wired LANs. In fact, wireless LAN protocols are similar to Ethernet and comply with the same form factors. The big difference, however, is that wireless LANs don't require wires. User Devices Users ... [full story]

Wireless PAN Technologies Wireless PAN technologies utilize both radio frequencies and infrared light, depending on the application. 802.15 The IEEE 802.15 standards working group focuses on the development of standards for wireless PANs and coordinates with other standards, such as 802.11 wireless LANs. The ... [full story]

Wireless PAN Systems Wireless PAN systems generally apply to individual users, and some offer support for multiple users. Take a closer look at several wireless PAN system configurations. Home and Small Office Many different system configurations of wireless PANs exist in the home ... [full story]

Wireless PAN Components Wireless PANs make use of both radio and infrared light technologies, which manufacturers embed in many different types of devices. User Devices Wireless PANs don't require much battery power to operate, making them ideal for small user devices, such as ... [full story]

Modulation: Preparing Signals for Propagation Modulation creates a radio or light signal from the network data so that it is suitable for propagation through the air. This involves converting the digital signal contained within the computer into an analog signal. As ... [full story]

Understanding Light Signals Light signals have been in use with communications systems for even longer than RF systems. Lanterns would provide a source of light to use with sending codes between ships at sea hundreds of years ago. Light guns are ... [full story]

Understanding RF Signals An RF signal is an electromagnetic wave that communications systems use to transport information through air from one point to another. RF signals have been in use for many years. They provide the means for carrying music to ... [full story]

Wireless Transceivers A wireless transceiver consists of a transmitter and a receiver. In the transmitter, a process known as modulation converts electrical digital signals inside a computer into either RF or light, which are analog signals. Amplifiers then increase the magnitude ... [full story]

Flow of Information Through a Wireless Network Certainly the reason for having a wireless network is to support the flow of information from one point to another without wires. As information flows through the network, the information changes form to efficiently ... [full story]

Information Signals Data is a type of information that the network stores in a computer or retrieves from it. As a result, wireless networks transfer data from one computer to another. This data can include e-mail messages, files, web pages, video, ... [full story]

Network Architecture The architecture of a network defines the protocols and components necessary to satisfy application requirements. One popular standard for illustrating the architecture is the seven-layer Open System Interconnect (OSI) Reference Model, developed by the International Standards Organization (ISO). OSI ... [full story]

Wireless Network System Components A wireless network consists of several components that support communications using radio or light waves propagating through an air medium. Some of these elements overlap with those of wired networks, but special consideration is necessary for all ... [full story]

Wireless Network Benefits People worldwide are learning of the benefits of wireless connectivity for checking e-mail, browsing the Internet, and accessing corporate applications. Ongoing advances in products that include wireless interfaces enable these people to unwire and reap the benefits of ... [full story]

Wireless Network Applications Wireless networks support many applications that benefit from user mobility and higher reliability because of less error-prone cabling. Furthermore, many wireless network applications realize significant cost savings because of increases in efficiencies and less downtime as compared to ... [full story]

Wireless Networks Defined A wireless network enables people to communicate and access applications and information without wires. This provides freedom of movement and the ability to extend applications to different parts of a building, city, or nearly anywhere in the world. ... [full story]

Storage Area Networks (SANs) Storage area networks (SANs) distribute data and other information to multiple storage devices that are interconnected by data networks. SANs allow for the sharing of resources and pooling of information in the form of shared files ... [full story]

LAN Telephony LAN telephony (sometimes called TeLANophy) use LAN systems to transport voice communications. LAN telephone technology is a merging of packetized voice with the high-speed data transmission ability of LAN systems. The ability to share data networks with voice ... [full story]

10 Gigabit Ethernet (10 GE) 10 Gigabit Ethernet (10 GE) is a data communication system that combines Ethernet technology with fiberoptic cable transmission to provide data communication transmission at 10 Gbps (10,000 Mbps). The specifications for 10 GE are being ... [full story]

Virtual Private Networks (VPN’s) Virtual private networks (VPN) network operators provide data connections to companies to allow interconnection of data networks. Companies use VPN to create MANs or WANs. The best examples of VPN’s today are ATM and frame relay ... [full story]

Internet Service Provider (ISP) Internet service provider is a company that provides an end user with data communication service that allows them to connect to the Internet. An ISP purchases a high-speed link to the Internet and divides up the ... [full story]