Shared Flashcard Set

Details

Networking+ Chapter 8
Chapter 8 Terms
66
Computer Networking
Undergraduate 4
10/10/2012

Additional Computer Networking Flashcards

 


 

Cards

Term
1G
Definition
The first generation of mobile phone service, popular in the 1970's and 1980's, which were routinely analog
Term
2.4GHz Band
Definition
The range of radio frequencies from 2.4 to 2.4835GHz. The 2.4GHz band, which allows for 11 unlicensed channels, is used by WLAN's that follow the popular 802.11b and 802.11g standards, however it is also used for cordless telephone and other transmissions making the 2.4 GHz band more susceptible to interference than the 5GHz. band.
Term
2G
Definition
Second generation mobile phone service popluar in the 1990's. 2G was the first standard to use digital transmission, and as a such, it paved the way for texting and media downloads on mobile web devices.
Term
3G
Definition
Third generation mobile phone service released in the early 2000's, that specifies throughputs of 384 Kbps and packet switching for data (but not voice) communications.
Term
4G
Definition
Fourth generation mobile phone service that is characterized by an all-IP, packet switched network for both data and voice transmission. 4G standards, released in 2008 also specifiy throughputs of 100Mbps for fast moving mobile clients, such as those in cars, and 1Gbps for slow moving mobile clients, such as pedestrians.
Term
5GHz band
Definition
A range of frequencies four frequency bands: 5.1GHz, 5.3GHz, 5.4GHz, 5.8GHz. It consists of 24 unlicensed bands, each 20MHz wide. the 5GHz band is used by WLANs that follow the 802.11a and 802.11n standards.
Term
802.11a
Definition
The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. 802.11a's high throughput , compared with 802.11b is attributable to its use of higher frequencies, its unique method of encoding data, and more available bandwidth.
Term
802.11b
Definition
The IEEE standard for a wireless networking technique that uses DSSS (direct-sequence-spread spectrum) signaling in the 2.4-2.4835 GHz frequency range (also called the 2.4GHz band). 802.11b separates the 2.4GHz band into 14 overlapping 22-MHz channels and provides a theoretical maximum of 11Mbps throughput.
Term
802.11g
Definition
The IEEE standard for a wireless networking technique designed to be compatible with 802.11b while using different encoding techniques that allow it to reach a theoretical maximum capacity 54 Mbps. 802.11g, like 802.11b, uses the 2.4GHz frequency.
Term
802.11n
Definition
The IEEE standard for a wireless networking technique that may issue signals in the 2.4 or 5Ghz band and can achieve actual data throughput between 65 and 600Mbps. It accomplishes this through several means, including MIMO, channel bonding and frame aggregation. 802.11n is backward compatible with 802.11a, b, and g.
Term
802.16
Definition
An IEEE standard for wireless MAN's. 802.16 networks may use frequencies between 2 and 66Ghz. Their antennas may operate in a line of sight or non-line of sight manner and cover 50 kilometers (30 miles). 802.16 connections can achieve a maximum throughput of 70 Mbps, though actual throughput diminishes as the distance between receivers increases. Several 802.16 standards exist. Collectively, they are known as WiMAX.
Term
802.16e
Definition
Currently, the most widely implemented version of WiMAX. With 802.16e, IEEE improved the mobility and the QoS characteristics of the technology , making it better suited to VOIP and mobile phone users. 802.16e is capable of 70Mbps throughput, but becasue bandwidth is shared and service providers cap data rates, most users actually experience 1-4Mbps throughput.
Term
802.16m
Definition
Also know as WiMAX 2, the IEEE standard for a version of 802.16 that achieves theoretical throuputs of 330 Mbps with lower latency and better quality for VoIP applications than previous WiMAX versions. 802.16m has been approved as a true 4G Technology. Manufacturers expect it to reach throughputs of 1Gbps in the near future.
Term
Access Point
Definition
A device used on wireless LAN's that transmits and receives wireless signals to and from multiple nodes and retransmits them to the rest of the network segment. Access points can connect a group of nodes with a network or two networks with each other. they may use directional or omnidirectional antennas.
Term
Active Scanning
Definition
A method used by wireless stations to detect the presence of an access point. In active scanning, the station issues a probe to each channel in its frequency range and waits for the access point to respond.
Term
Ad Hoc
Definition
A type of wireless LAN in which stations communicate directly with each other (rather than using access point).
Term
Association
Definition
In the context of wireless networking, the communication that occurrs between a station and an access point to enable the station to connect to the network via that access point.
Term
Backhaul
Definition
AN intermediate connection between subscriber networks and a telecommunications carrier's network.
Term
Beacon frame
Definition
In the context of wireless networking, a frame issued by an access point to alert other nodes of its existence.
Term
BSS
Basic Service Set
Definition
In IEEE terminology,a group of stations that share an access point.
Term
BSSID
Basic Service Set Identifier
Definition
In IEEE terminology the identifier for a BSS.
Term
Cell
Definition
In a cellular network, an area of coverage serviced by an antenna and base station.
Term
Channel Bonding
Definition
In the context of 802.11n wireless technology, the combination of two 20MHZ frequency bands to create one 40Mhz frequency band that can carry more than twice the amount of data that a single 20MHZ band could. It's recommended for use only in the 5Ghz range because this band has more available channels and suffers less interference than the 2.4GHz band.
Term
CSMA/ca
Carrier Sense Multiple Access with Collision Avoidance
Definition
A network access method used on 802.11 wireless networks. In CSMA/CA, before a node begins to send data it checks the medium. if it detects no transmission activity, it waits a brief, random amount of time, and then its transmission. if the node does not detect activity, it waits a brief period of time before checking the channel again. CSMA/CA does not eliminate, but minimizes, the potential for collisions.
Term
Diffraction
Definition
In the context of wireless signal propagation, the phenomenon that occurs when an electromagnetic wave encounters an obstruction and splits into secondary waves. the secondary waves continue to propagate in the direction in which they were split. If you could see wireless signals being diffracted, they would appear to be bending around the obstacle. Objects with sharp edges-including the corners of walls and desks-cause diffraction.
Term
Directional Antenna
Definition
A type of antenna that issues wireless signals along a single direction or path.
Term
Downlink
Definition
In the context of wireless transmission, the connection between a carrier's antenna and a client's transceiver-for example, a smartphone.
Term
DSSS
Direct Sequence Spread Spectrum
Definition
A transmission technique in which a signal's bits are distributed over an entire frequency band at once. Each bit is coded so that the receiver can reassemble the original signal upon receiving the bits.
Term
ESS
Extended Service Set
Definition
A group of access points and associated stations (or basic service sets) connected to the same LAN.
Term
ESSID
Extended Service Set Identifier
Definition
A special identifier shared by BSS's that belong to the same ESS.
Term
Fading
Definition
A variation in a wireless signal's strength as a result of some of the electromagnetic energy being scattered, reflected, or diffracted after being issued by the transmitter.
Term
FHSS
Frequency Hopping Spread Spectrum
Definition
A wireless signaling technique in which a signal jumps between several different frequencies within a band in a synchronization pattern known to the channel's receiver and transmitter.
Term
Fixed
Definition
A type of wireless system in which the locations of the transmitter and receiver are static. In a fixed connection, the transmitting antenna focuses its energy directly toward the receiving antenna. This results in point-to-point link.
Term
GEO
Geosynchronous Earth orbit
Definition
The term used to refer to a satellite that maintains a constant distance from a point on the equator at every point in its orbit. Geosynchronous orbit satellites are the type used to provide satellite internet access.
Term
Handoff
Definition
The transition that occurs when a cellular when a cellular network client moves from one antenna's coverage area to another.
Term
HSPA+
High Speed Packet Access Plus
Definition
A 3G mobile wireless technology released in 2008 that uses MIMO and sophisticated encoding techniques to achieve a maximum 84Mbps downlink throughput and 11Mbps uplink throughput in its current release. Advances in more efficiently using limited channels and incorporating more tennis in MIMO promise to push the maximum downlink data rate to 336 Mbps.
Term
Infrastructure WLAN
Definition
A type of WLAN in which stations communicate with an access point and not directly with each other.
Term
IWCONFIG
Definition
A command line utility for viewing and setting wireless interface parameters on Linux and UNIX workstations.
Term
LOS
Line of Sight
Definition
A wireless signal path or path that travels directly in a straight line from its transmitter to its intended receiver. This type of propagation uses the least amount of energy and results in the reception of the clearest possible signal.
Term
LTE
Long term Evolution
Definition
A 4G cellular network technology that achieves downlink data rates of up to 1Gbps and uplink rates up to 500 Mbps. ATT&T and Verizon have adopted LTE for their high-speed wireless data networks.
Term
MIMO
Multiple In-Multiple Out
Definition
In the context of 802.11n wireless networking, the ability for access points to issue multiple signals to stations, thereby multiplying the signal's strength and increasing their range and data carrying capacity. Because the signals follow multipath propagation, they must be phased adjusted when they reach their destination.
Term
Mobile
Definition
A type of wireless system in which the receiver can be located anywhere within the transmitter's range. This allows the receiver to roam from one place to another while continuing to pick up its signal.
Term
MSC
Mobile Switching center
Definition
A carrier's facility to which multiple cellular base stations connect. An MSC might be located inside a telephone company's central office or it might stand alone and connect to the central office via fiber optic cabling or a microwave link. Equipment at an MSC manages mobile clients, monitoring their location and usage patterns and switches cellular calls. It also assigns each mobile client IP address.
Term
Multipath
Definition
The characteristic of wireless signals that follow a number of different paths to their destination for example, because of reflection, diffraction, and scattering.
Term
Omnidirectional Antenna
Definition
A type of antenna that issues and receives wireless signals with equal strength and clarity in all directions. This type of antenna is used when many different receivers must be able to pick up the signal , or when the receiver's location is highly mobile.
Term
Passive Scanning
Definition
In the context of wireless networking , the process in which a station listens to several channels within a frequency range for a beacon issued by an access point.
Term
Probe
Definition
In 802.11 wireless networking a type of frame issued by a station during active scanning to find nearby access points.
Term
Radiation Pattern
Definition
The relative strength over a three dimensional area of all the electromagnetic energy an antenna sends or receives.
Term
Range
Definition
the geographical are in which signals issued from an antenna or wireless system can be consistently and accurately received.
Term
Reassociation
Definition
In context of wireless networking , the process of a station establishing a connection (or associating) with a different access point.
Term
Reflection
Definition
In the context of wireless, the phenomenon that occurs when an electromagnetic wave encounters an obstacle and bounces back toward its source. A wireless signal will bounce off objects whose dimensions are large compared with the signal's average wavelength.
Term
Roaming
Definition
In wireless networking, the process that describes a station moving between BSSs without losing connectivity.
Term
RTS/CTS
Request to send/clear to send
Definition
AN exchange in which a wireless station requests the exclusive right to communicate with an access point and the access point confirms that it has granted that request.
Term
Scanning
Definition
The process a wireless station undergoes to find an access point.
Term
Scattering
Definition
The diffusion of a wireless signal that results from hitting an object that has smaller dimensions compared with the signal's wavelength. Scattering is also related tot he roughness of the surface a wireless signal encounters. The rougher the surface, the more likely a signal is to scatter when it hits that surface.
Term
Site Survey
Definition
In the context of wireless networking, an assessment of client requirements, facility characteristics,and coverage areas to determine an access point arrangement that will ensure reliable wireless connectivity within a given area.
Term
Spread Spectrum
Definition
A type of wireless transmission in which lower level signals are distributed over several frequencies simultaneously. Spread spectrum transmission is more secure than narrowband.
Term
SSID
Service at Identifier
Definition
A unique character string used to identify an access point on an 802.11 network
Term
Station
Definition
An end node on a network, used most often in the context of wireless networks.
Term
Transponder
Definition
The equipment on a satellite that receives an uplinked signal from Earth, amplifies the signal, mnodifies its frequency then retransmits it (in a downlink) to an antenna on Earth.
Term
Uplink
Definition
In the context of wireless transmission, the connection between a client's transceiver and a carrier's antenna.
Term
Wireless
Definition
A type of signal made of electromagnetic energy that ravels through the air.
Term
Wireless Gateway
Definition
An access point that provides routing functions and is used as a gateway.
Term
Wireless Router
Definition
An access point that provides routing functions.
Term
Wireless Spectrum
Definition
A continuum of electromagnetic waves used for data and voice communication. the wireless spectrum (as defined by the FCC, which controls its use) spans frequencies between 9KHz and 300 GHz. Each type of wireless service can be associated with one area of the wireless spectrum.
Term
WLAN
Wireless LAN
Definition
A LAN that uses wireless connections for some or all of its transmissions.
Supporting users have an ad free experience!