How many CRCs is considered "acceptable"?

[IllegalOperation]

Hello all. I am in a debate with a colleague as to how many CRCs are acceptable, at least to the point before it starts degrading system performance.

Obviously NO CRCs are acceptable in a perfect environment, but right now we have a max of around 5% on one of our links. The link is basically from a router to a switch.

I am being told that you should only worry about CRCs when it gets up to like 10% (as far as performance goes at least). I believe its lower. At what point do you actually notice decline in speed? Is it ok to average at like 1% - for example?

Thanks

 

[rburke]

From my past experience anything above 1 CRC per 1 million bytes should be investigated. Reason being that most of the time CRC percentages won't just stay at a certain level. They will most likely increase to the point of disrupting service.

If you are experiencing the CRC's on a WAN then I would get telco testing performed along with switching out any cabling from the demarc to your border router. If it is occuring on a LAN then I would replace the cable and make sure you specify the speed and duplex of the devices on both ends.

Let me know if this helps.

Burke

 

[IllegalOperation]

Greatly appreciated rburke.

To be honest with you, it is an actual DOCSIS system. Usually CRCs between the modems and CMTS means there is an upstream noise problem....but I dont think that is the case with what I got. I just wanted to compare what I am seeing to an actual telco/LAN environment, performance-wise....