bce packet loss

[YongHyeon PYUN]

On Wed, Jul 06, 2011 at 02:28:19PM -0700, David Christensen wrote:
> > You had 282 RX buffer shortages and these frames were dropped. This
> > may explain why you see occasional packet loss. 'netstat -m' will
> > show which size of cluster allocation were failed.
> > However it seems you have 0 com_no_buffers which indicates
> > controller was able to receive all packets destined for this host.
> > You may host lost some packets(i.e. non-zero mbuf_alloc_failed_count)
> > but your controller and system was still responsive to the network
> > traffic.
> > 
> > Data sheet says IfHCInBadOctets indicates number of octets received
> > on the interface, including framing characters for packets that
> > were dropped in the MAC for any reason. 
> 
> The IfHcInBadOctets counter says the controller received X bytes 
> that were bad on the wire (collisions, FCS errors, etc.).  A value

I thought that too. But other counters such as FCS, FAE, Collisions,
Jabbers were all zero.

> of 539,369 would equal about 355 frames @ 1518 bytes per frame.
> How bad that is really depends on the amount of time the server
> was running.  The minimum bit-error rate (BER) for 1000Base-T is 
> 10^-12, so running at line rate you'd expect to see an error very
> 1000 seconds according to the following link:
> 
> http://de.brand-rex.com/LinkClick.aspx?fileticket=TFxnnLPedAg%3D&tabid=1956&mid=5686
> 
> Most vendors design to greater than 10^-12 and you're probably not
> running at line rate all the time so you should see fewer errors.
> In my testing I can go for days without seeing any errors, but if
> you run long enough or have marginal interconnects/cabling the 
> error rate will rise.
> 
> Dave
> 
>