Forward Erasure Correction (FEC) and network performance

Mikael Abrahamsson swmike at
Fri Apr 10 14:00:41 CDT 2009

On Fri, 10 Apr 2009, Lamar Owen wrote:

> This sounds pretty good, until you realize that it means you can expect 
> 36 errors in 10 hours on a 100% utilized gigabit fiber link.

Well, it means this is still ok according to standard. In real life, if 
you engineer your network to be within the optical levels they should be, 
you get GigE links that at the highest, have single digit CRC errors per 
month, at the lowest, have 0 CRC errors month after month even with a lot 
of traffic.

BER starts happening very steeply when you approch the optical limit, it 
might go from 10^-20 to 10^-14 in just a few dB of optical level change.

Mikael Abrahamsson    email: swmike at

More information about the NANOG mailing list