[c-nsp] 4x10G Etherchannel overruns

[Laurent Dumont]

What does the CPU look like when the traffic is flowing? I'd be curious 
to also see the traffic breakdown per interface - not the Port-Channel 
itself.


On 03/08/2017 06:49 PM, Jean-Francois.Dube at videotron.com wrote:
> Hi Peter,
>
> Do the overrun match with input drops on the interfaces input queue? Maybe
> this traffic being punted to CPU?
>
> I had this issue on a Cisco 7600 when using "mpls ldp explicit-null" and
> many Gbps of traffic needed to be sent to CPU.
>
> Hope this helps.
>
> Cheers,
>
> JF
>
> Jean-François Dubé
> Technicien, Opérations Réseau IP
> Ingénierie Exploitation des Réseaux
> Vidéotron
>
> "cisco-nsp" <cisco-nsp-bounces at puck.nether.net> a écrit sur 2017-03-03
> 12:04:28 :
>
>> De : "Peter Kranz" <pkranz at unwiredltd.com>
>> A : <cisco-nsp at puck.nether.net>,
>> Date : 2017-03-03 12:09
>> Objet : [c-nsp] 4x10G Etherchannel overruns
>> Envoyé par : "cisco-nsp" <cisco-nsp-bounces at puck.nether.net>
>>
>> On a WS-X6908-10G DCEF2T line card with SUP2T's, I ran into overruns
>> yesterday on a 4x10G etherchannel that I am at a loss to resolve:
>>
>>
>>
>> Constantly increasing overrun counter:
>>
>>     6418130558941 packets input, 9277559958229871 bytes, 0 no buffer
>>
>>       Received 668274 broadcasts (0 IP multicasts)
>>
>>       0 runts, 190 giants, 0 throttles
>>
>>       192 input errors, 1 CRC, 0 frame, 51591389 overrun, 0 ignored
>>
>>
>>
>> Latency into the router rose by 40ms when these overrun's started to
> appear
>>
>>
>> This happened at a BW of ~28 Gbps
>>
>>
>>
>> I've built the etherchannel in this manner:
>>
>>
>>
>> Index   Load      Port          EC state       No of bits
>>
>> ------+------+------------+------------------+-----------
>>
>> 0      0A            Te1/1             Active   2
>>
>> 3      81            Te1/2             Active   2
>>
>> 1      60            Te1/3             Active   2
>>
>> 2      14            Te1/4             Active   2
>>
>>
>>
>> Is it necessary to instead stagger 1/1, 1/3, 1/5, 1/7 to spread the load
>> across the card ASICs? I didn't think the WS-X6908 was an oversubscribed
>> card so didn't bother initially.
>>
>>
>>
>> Peter Kranz
>> www.UnwiredLtd.com <http://www.unwiredltd.com/>
>> Desk: 510-868-1614 x100
>> Mobile: 510-207-0000
>> pkranz at unwiredltd.com <mailto:pkranz at unwiredltd.com>
>>
>>
>>
>> _______________________________________________
>> cisco-nsp mailing list  cisco-nsp at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at http://puck.nether.net/pipermail/cisco-nsp/
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/