Glossary in Software

Generation Data Matrix in Software Glossary

line of sight (LOS) Visual LOS is the ability to see along a virtual line between two points RF LOS must also consider the Fresnel zones to ensure effective communications loss The lowering of a signal s strength Often measured in decibels in wireless networks MAC filtering Each networking device has a Media Access Control (MAC) address that is unique to the device Wireless networks can allow or disallow device connectivity based on the MAC address of the device, and this is known as MAC filtering mesh network A mesh network is a network having two or more paths to any node Examples of possible mesh networks include Wi-Fi-based mesh, ZigBee, TCP/IP, and other routed protocols message integrity code (MIC) The IEEE term used for a message authentication code; it is a hash used for verification of data integrity MIC uses a keyed hash, which means that both the encryption key and the message (data) are passed through the hashing algorithm to generate the hash milliwatt 1/1000 of a watt Used to measure RF signal strength because of the low levels of strength needed to communicate on wireless networks mini-PCI A form factor used for devices mostly in laptop computers Many wireless devices, installed in laptops, are actually mini-PCI adapters modulation The process used to transmit information on a carrier signal by varying one or more of the properties of the signal multipath RF signals arrive at a receiver from a single transmitter but along different paths These different paths are the direct path and reflected paths This can result in signal loss because of the signals arriving out of phase or at differing times However, MIMO takes advantage of multipath to improve bandwidth Multiple Input/Multiple Output (MIMO) A technology, upon which 80211n is based, that takes advantage of the normally detrimental problem of

multipath to create more data bandwidth in wireless networks by reducing bit error rates and improving throughput

near/far A term used to describe the problem that arises when wireless nodes are far from the access point transmitting with low power and other wireless nodes are closer to the access point or transmitting with higher power This results in the far node not being seen by the access point and, therefore, having difficulty communicating omnidirectional antennas Antennas that radio energy in a donut fashion around the antenna These include dipole and rubber-ducky antenna types open system authentication The default authentication for the IEEE 80211 specification Shared-key authentication is the alternative The authenticating station sends a frame to the other station (an access point in infrastructure mode) requesting authentication and containing the authenticating station s identification The receiving station (again, the access point in an infrastructure network) sends back a frame that either authenticates access or denies access to the authenticating station Open system authentication is used with 8021X port-based authentication solutions suggested in 80211i PCI Peripheral Component Interconnect (PCI) is a high-speed connection port for devices attached to computers Some wireless network interface cards (NICs) use PCI slots for their interface connections PCMCIA Personal Computer Memory Card International Association (PCMCIA) is an interface used to connect devices to laptop computers Some wireless network interface cards (NICs) use PCMCIA interfaces PCMCIA cards often function in the newer CardBus slots on modern laptop computers Today, PCMCIA devices are often called PC Card devices point-to-multipoint A wireless link that includes multiple points connecting to a single central point This is much like a star network topology in that all the sites communicate back to the central location point-to-point other system

polarization The plane of the electrical field in an RF signal Antennas are usually said to be vertically or horizontally polarized This polarization determines, to a great extent, the direction of the RF signal Power over Ethernet (PoE) A technology that allows for the transmission of power over standard Ethernet cables PoE can be used to power access points and other wireless devices in locations where local power outlets are not available power save mode One of two power management modes in which a wireless client may operate In power save mode, the client wakes at predetermined intervals to check for packets intended for the client push-button security A newer security technology used in many wireless devices While vendors use different names for it, the concept is the same: the access point negotiates the best security that is compatible with the access point and the connecting client radio frequency (RF)