[c-nsp] Huge number of input queue drops on 6500

Stig Johansen stig.johansen at ementor.no
Sun May 11 19:10:47 EDT 2008


>> We just discovered a very weird problem, we're not sure what to
>> attribute it to. We run a port-channel between a cisco (6509E,
>> WS-X6548-GE-TX) and a Huawei NE40E. Port channel consists of 2 copper
>> links and runs at about 1.2G. We've noticed huge number of input
queue
>> drops and overruns:

> Entirely expected (we've seen similar). The 6548 is overbooked 8:1,
each
> ASIC handling 8 ports with 1 Gig towards the backplane bus. 2/5 and
2/8
> are on the same ASIC and drops are expected if you run above 1 Gbps.
You
> may have better luck if you spread the channels on two different
ASICs.
> For high bandwidth applications a card with small or no overbooking is
> better (e.g. the 6724 / 6748 family).

You should look at this URL:

http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note
09186a00801751d7.shtml#ASIC

as it has all the information about this problem and other
etherchannel-related restrictions using this card.

Best regards,
Stig Meireles Johansen


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