[LARTC] Ethernet packet loss - frame errors

[Stephen Hemminger]

On Sat, 14 Oct 2006 15:18:32 +0200
Justin Schoeman <justin at expertron.co.za> wrote:

> Stephen Hemminger wrote:
> > On Fri, 13 Oct 2006 10:26:14 +0200
> > Justin Schoeman <justin at expertron.co.za> wrote:
> > 
> >> Hi all,
> >>
> >> I have the following problem. A Linux box configured as a bridge. One 
> >> interface connects to the router via a crossover cable, the other 
> >> connects to a switch via the cable that used to go to the router.
> >>
> >> Now I get the following:
> >>
> >> [root at localhost net]# ifconfig eth3
> >> eth3      Link encap:Ethernet  HWaddr 00:03:2D:07:61:5D
> >>            UP BROADCAST MULTICAST  MTU:1500  Metric:1
> >>            RX packets:1969134 errors:0 dropped:0 overruns:0 frame:176459
> >>            TX packets:2186662 errors:0 dropped:0 overruns:0 carrier:0
> >>            collisions:0 txqueuelen:1000
> >>            RX bytes:492595115 (469.7 Mb)  TX bytes:579725462 (552.8 Mb)
> >>            Interrupt:17
> >>
> >> eth3 is the interface that connects to the switch.  As you can see, 1 in 
> >> 10 rx packets are framing errors.
> >>
> >> What are possible causes for this? The cable is a constant, so is not 
> >> likely to cause problems, so what else can possibly cause such a high 
> >> number of frame errors?
> >>
> >> Any help appreciated.
> >>
> >> Thanks,
> >>
> >> Justin
> >>
> > 
> > What speed and driver?
> 
> sky 2 driver, hardcoded for 100Mbps full duplex.
> 

In that driver, frame errors come from receiving fragments. Fragments
are any packet shorter 64 bytes and has an invalid CRC.

These might occur if you have got a duplex mismatch.

-- 
Stephen Hemminger <shemminger at osdl.org>