[LARTC] Ethernet packet loss - frame errors

[LARTC] Ethernet packet loss - frame errors

[Justin Schoeman]

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@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

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Re: [LARTC] Ethernet packet loss - frame errors

[Andrei Sandu]

[-- Attachment #1.1: Type: text/plain, Size: 1280 bytes --]

Possibly the length of the cable ?

On 10/13/06, Justin Schoeman <justin@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@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
>
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> LARTC mailing list
> LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
>

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[-- Attachment #2: Type: text/plain, Size: 143 bytes --]

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Re: [LARTC] Ethernet packet loss - frame errors

[Justin Schoeman]

Andrei Sandu wrote:
> Possibly the length of the cable ?

It is a 5m cable.  It is also the 'common' cable - it is unplugged from 
the router and plugged into the bridge (the other side stays in the switch).

-justin


> On 10/13/06, *Justin Schoeman* <justin@expertron.co.za 
> <mailto:justin@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@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
> 
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> 
> 
> 
> ------------------------------------------------------------------------
> 
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Re: [LARTC] Ethernet packet loss - frame errors

[Stephen Hemminger]

On Fri, 13 Oct 2006 10:26:14 +0200
Justin Schoeman <justin@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@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?
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Re: [LARTC] Ethernet packet loss - frame errors

[Justin Schoeman]

Stephen Hemminger wrote:
> On Fri, 13 Oct 2006 10:26:14 +0200
> Justin Schoeman <justin@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@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.

-justin
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Re: [LARTC] Ethernet packet loss - frame errors

[Justin Schoeman]

OK - Just finished more testing, and it seems to be a bug in the sky2 
driver...

ping -s 1450 -f xxx.xxx.xxx.xxx

works perfectly, but

ping -s 1500 -f xxx.xxx.xxx.xxx

fails 100% with all packets being logged as frame errors.

-justin

Justin Schoeman 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@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
> 
> _______________________________________________
> LARTC mailing list
> LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
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Re: [LARTC] Ethernet packet loss - frame errors

[Stephen Hemminger]

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

> Stephen Hemminger wrote:
> > On Fri, 13 Oct 2006 10:26:14 +0200
> > Justin Schoeman <justin@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@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@osdl.org>
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Re: [LARTC] Ethernet packet loss - frame errors

[Stephen Hemminger]

On Mon, 16 Oct 2006 16:09:50 +0200
Justin Schoeman <justin@expertron.co.za> wrote:

> OK - Just finished more testing, and it seems to be a bug in the sky2 
> driver...
> 
> ping -s 1450 -f xxx.xxx.xxx.xxx
> 
> works perfectly, but
> 
> ping -s 1500 -f xxx.xxx.xxx.xxx
> 
> fails 100% with all packets being logged as frame errors.
> 
> -justin
>

Do you have an MTU mismatch?  If the sender assumes it can send
large packets, and the receiver doesn't expect them it might cause it.
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