Forward Error Correction (FEC) is a technology which allows the
receiver of a message to detect and correct most single bit errors,
and many multi-bit errors ( error bursts) without referring to
the transmitter of the message. While commonly implemented in
hardware digital logic, FEC can also be implemented in either
here for more information on FEC implementations based in firmware)
or software (such as a device driver) as described here.
Effect of Error Rate upon Throughput
In PC based communications, using simple protocol technologies
such as SLIP / PPP / HDLC / SDLC / and most custom protocols,
the data error rate has an effect upon data throughput. Simply
put, the higher the error rate, the lower the throughput. This
effect is vastly amplified by the connection's propagation delays.
Simply put again, the larger the propagation delay, the reduction
in data throughput can be HUGE.
In a typical case where 22mS of propagation latency exists due
to geosynchronous satellite connection, a simple single or multi
bit error can stall a link for periods far greater than the 44mS
of retransmit propagation burden. This is often due to the additional
burden imposed by detection of dropped packets being performed
in a layer which is separated from the physical link layer, such
as scenario where TCP is a remote layer from the serial port device.
Stall times arising from single bit errors on SLIP (Serial Link
IP), for example, of 1 to 5 seconds are not unusual.
Serial Port Forward Error Correct ("SP FEC")
This all done in a fashion whereby the serial port appears as
a standard serial port to Operating Systems, Routers, and Application
software. Most common single bit and multi bit error burst no
longer stall the link, resulting an improvement in throughput.
Intangibly also, by eliminating data stalls when browsing content,
can transform end user frustration into end user satisfaction.
Data Flow Diagram
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