Cooper Bussmann Wireless Ethernet & Device Server BU-945U-E 802.11 DSSS User Manual

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 website has its own specific IP address on the Internet.

DSL

Digital Subscriber Line Various technology protocols for high-speed data, voice and video transmission over ordinary twisted-pair copper POTS (Plain Old Telephone Service) telephone wires.

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Cooper Bussmann BU-945U-E 802.11 DSSS user manual Ack, Csma/Ca, Csma/Cd, Dhcp, Dns Dsl