USRobotics U.S. Robotics SureConnect ADSL Ethernet/USB Router User Manual

Page 241

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U.S. Robotics SureConnect ADSL Ethernet/USB Router User Guide

ESP (Encapsulating Security Payload) – ESP provides confidentiality. Optionally,
ESP also provides integrity, authentication, anti-replay service, and limited traffic flow
confidentiality. Options selected at the time of Security Association establishment
determine provided services. For confidentiality, shared ESP supports shared key
encryption algorithms, such as DES and Triple DES.

F

Filter - Operating parameter used in LAN bridges and routers. When set, the filter
causes bridges and routers to block transfer of packets between LANs. The term
"filter" also applies to a hardware device, such as a microfilter. When installed, this
device reduces interference between DSL signals and telephone signals.

Forward Delay Time - Timeout value employed by all bridges in the bridged LAN.
The root sets the forward delay value.

FM (Frequency Modulation) Modulation method used by modems, radio, and DSL
equipment. The signal modulates or alters the frequency or pitch of the carrier. In
regular FM, the carrier is a sinewave. The frequency of the modulated carrier changes
in proportion to signal amplitude. FM creates an infinite number of sidebands. These
sidebands contain the signal data. With an equivalent signal, FM tends to require
more bandwidth than AM does. FM's advantage is that it’s less subject to impulse
noise and static than AM is.

Frame - Variable length information unit that contains packets. Also refers to a
transmission frame, a fixed-length unit that carries bits across a physical link. A
transmission frame is a framed transport component. DSL technologies use frames.
Also refers to a frame of video, one image in a video sequence

G

Gateway - Entrance to and exit from a communications network.

G.DMT - The ADSL standard approved by the International Telecommunications
Union (ITU). G.DMT indicates full-rate ADSL, which provides standards for higher
speed ADSL than G.Lite. G.DMT provides maximum data rates of 8 Mbps
downstream from the subscriber and 1.5 Mbps upstream from the subscriber.

G.lite - Standard way to install Asymmetric Digital Subscriber Line service. Over
regular phone lines, G.Lite makes possible Internet connections to home and
business computers at up to 1.5 Mbps. Officially known as G.992.2.

H

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