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Common questions

What causes high FEC errors?

What causes high FEC errors?

Re: FEC Errors Errors are caused by noise corrupting bits on the line (several million bits are transmitted per second and if one is corrupted, i.e. becomes 1 rather than 0 or vice versa, that is an error).

Are FEC errors normal?

Its normal to see FEC errors on an Interleaved line and rather than anything to be too concerned about its more an indication that the Interleaving & Error Correction process is working and doing what it should.

What is FEC error in router?

Forward error correction (FEC) is a method of obtaining error control in data transmission in which the source (transmitter) sends redundant data and the destination (receiver) recognizes only the portion of the data that contains no apparent errors.

What causes downstream FEC errors?

Re: Extremely high amount of fec errors on downstream They are caused by running at the lower 3dB signal to noise ratio.

Do FEC errors matter?

Yes. CRC errors mean that packets have to be re-transmitted. FEC errors don’t affect line speed, but indicate that “the Interleaving & Error Correction process is working and doing what it should”.

What is FEC and CRC errors?

FEC operates on the principle of sending redundant data that can be deployed to correct some errors at the Receiver while CRC is an error detection code used to detect errors. A receiver uses the FEC to correct any errors in a FLIT after which it applies the CRC check on the 250 Bytes that are protected by the CRC.

How many FEC errors are normal?

An acceptable FEC rate is 100 per minute or 1500 within 15 minutes or 6000 per hour or less. Line interference from storm, electric motors, noisy ac line can cause increase in FECs.

How many CRC errors are acceptable?

And the acceptable range IMO is 0 (CRC/CV) errors.

Does PCIe use FEC?

The PCI Express ® (PCIe ®) 6.0 specification will feature two primary mechanisms to correct errors: Forward Error Correction (FEC) and Cyclic Redundancy Check (CRC). Each 256-byte FLIT comprises of 242 bytes of payload which are protected by 8 Bytes of CRC.

WHAT ARE NEAR END CRC errors?

CRC errors are bad, and the fact that those are near end means they are errors the modem picks up on the incoming signal – meaning that the frames coming into the modem are damaged in some way and the modem must request they be resent, which slows down your connection.

What is FEC and CRC?

What is PCIe FLIT mode?

The FLIT mode is a significant departure for the PCIe 6.0 specification, and the improved bandwidth that results from low overhead amortization allows for high bandwidth efficiency, low latency and reduced area.

What is FEC 2/3 in satellite internet?

Part of the data stream is used solely to correct errors in the downlink stream from the satellite. This prevents the picture breaking up. A FEC of 2/3 means that every third bit of data is used to correct errors in the previous two bits.

How do better FEC codes work?

Better FEC codes typically examine the last several dozen, or even the last several hundred, previously received bits to determine how to decode the current small handful of bits (typically in groups of 2 to 8 bits).

What is the advantage of a FEC of 2/3?

This prevents the picture breaking up. A FEC of 2/3 means that every third bit of data is used to correct errors in the previous two bits. Here signal would be more robust and can be received easier, with less breakup in rain, for example. It is less efficient, with not so much data available to transmit the picture.

What is interleaving FEC coded data?

Interleaving FEC coded data can reduce the all or nothing properties of transmitted FEC codes when the channel errors tend to occur in bursts. However, this method has limits; it is best used on narrowband data.