Panasonic FP-D250 User Manual page 588

Foirl (Fiber Optic Inter-Repeater Link) Defined in IEEE 802.3 and implemented over
two fiber links, transmit and receive, this medium may be up to 500m and 1 kilometer
long depending on the number of repeaters in the network.
Fractional services Bandwidth available from carriers in increments of 64Kbit/s,
such as Mercury's Switchband.
Frame A group of bits sent over a link. A frame may contain control and addressing
information, as well as error detection - for example CRC information - and forward
error correction information. The size and composition of the frame varies according
to the protocol. Often used synonymously with packet.
Frame relay A data communications interface originating from ISDN designed to
provide high speed frame or packet transmission with minimum delay and efficient
use of bandwidth. It is a variation on the X.25 interface and form of fast packet
switching. It derives its name from using the Data Link or "frame" OSI layer Two to
route or "relay" a packet directly to its destination instead of terminating the packet at
each switching node. This eliminates processing overheads and increases throughput
speed. Based on the ITU-TS Lap-D standard, it uses variable-length packets and
applicable only to sub-broadband, T3/E3 or lower, data transmission. Like Ethernet,
or token ring, frame relay assumes that connections are reliable. It does not have
error detection and error control within the network, which helps to speed up the
protocol. When errors occur frame relay relies on higher level protocols for error
control. Frame relay is often viewed as a replacement for X.25, primarily for LAN-to-
LAN bursty traffic. Voice over frame relay is available, but the subject of debate. It
will also become an access method for ATM-based WANs.
Front end The client part of a client/server application that requests services across
a network from a server, or back end. It typically provides an interactive interface to
the user, for example, a data entry front end, allowing data to be entered into a
server through the use of SQL.
FTP (File Transfer Protocol) The TCP/IP standard, high-level protocol for transferring
files from one machine to another. Usually implemented as applications level
programs, FTP uses the Telnet and TCP protocols. Full duplex - A channel capable
of transmitting in both directions at the same time.
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