Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
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www.cooperbussmann.com/wirelessresources
Rev Version 1.0.12-Beta7
Appendix B -
GLOSSARY
ACK
Acknowledgment.
Access Point
An access point connects wireless network Stations (or Clients) to other Stations within the
wireless network and also can serve as the point of interconnection between the wireless
network and a wired network. Each Access Point can serve multiple users within a defined
network area. Also known as a base station.
Antenna Gain
Antennae don t increase the transmission power, but focus the signal more. So instead of
transmitting in every direction (including the sky and ground) antenna focus the signal usually
either more horizontally or in one particular direction. This gain is measured in decibels
Bandwidth
The maximum data transfer speed available to a user through a network .
Bridge
A bridge is used to connect two local area networks together. Bridges are typically used to
connect wireless networks to wired networks. Typically, bridges will transfer messages
between networks only when the message destination is on the other network. Messages
that are destined for the same network as they originated on are not passed to the other
network, therefore reducing traffic on the entire network.
Collision
avoidance
A network node procedure for proactively detecting that it can transmit a signal without
risking a collision with transmissions from other network nodes.
Client / Sta /
Station
A device on a network that gains access to data, information, and other devices through a
Server (Access Point).
Crossover
cable
A special cable used for networking two computers without the use of a hub. Crossover
cables may also be required for connecting a cable or DSL modem to a wireless gateway or
access point. The cable is wired so that the signals crossover , connecting transmit signal
on one side to receiver signals on the other.
CSMA/CA
Carrier Sense Multiple Access/Collision Avoidance is a listen before talk method of
minimizing (but not eliminating) collisions caused by simultaneous transmission by multiple
radios. IEEE 802.11 states collision avoidance method rather than collision detection must be
used, because the standard employs half duplex radios
radios capable of transmission or
reception
but not both simultaneously. Unlike conventional wired Ethernet nodes, a WLAN
station cannot detect a collision while transmitting. If a collision occurs, the transmitting
station will not receive an ACKnowledge packet from the intended receive station. For this
reason, ACK packets have a higher priority than all other network traffic. After completion of
a data transmission, the receive station will begin transmission of the ACK packet before any
other node can begin transmitting a new data packet. All other stations must wait a longer
pseudo randomized period of time before transmitting. If an ACK packet is not received, the
transmitting station will wait for a subsequent opportunity to retry transmission.
CSMA/CD
Carrier Sense Multiple Access/Collision Detection is the access method used on an Ethernet
network. A network device transmits data after detecting that a channel is available.
However, if two devices transmit data simultaneously, the sending devices detect a collision
and retransmit after a random time delay.
DHCP
Dynamic Host Configuration Protocol A utility that enables a server to dynamically assign IP
addresses from a predefined list and limit their time of use so that they can be reassigned.
Without DHCP, an IT Manager would have to manually enter in all the IP addresses of all the
computers on the network. When DHCP is used, whenever a computer logs onto the
network, it automatically gets an IP address assigned to it.
Dial-up
A communication connection via the standard telephone network, or Plain Old Telephone
Service (POTS).
DNS
Domain Name Service A program that translates URLs to IP addresses by accessing a
database maintained on a collection of Internet servers. The program works behind the
scenes to facilitate surfing the Web with alpha versus numeric addresses. A DNS server
converts a name like mywebsite.com to a series of numbers like 107.22.55.26. Every
