[c-nsp] Constant output drops on etherchannel

[Kevin Graham]

See the rest of the thread -- don't bother with those GBICs; if they were a problem, it would manifest itself as input/output errors or link flaps. An output drop means the packets was dropped before ever being transmitted, not mangled by crappy transceivers in-flight.

[sent from my mobile]

On Jan 14, 2011, at 1:08 PM, "Robert VanOrmer" <vanormer at gmail.com> wrote:

> I am experiencing a very similar issue on the C3750E platform w/ 12.2(52)SE.
> We have 5 switches in a cluster, port-channeled with (2) Gig interfaces L2
> to distro (6500's) with excessive output drops even at low utilization.  No
> QoS enabled.  I am using the Cisco TwinGig Converter Modules for uplinks..
> We have a TAC case open, but no progress yet.  I'd be interested in knowing
> if you find a cause. I am going to try swapping GBICs over the weekend.
> 
> 
> 
> Thanks,
> 
> Rob
> 
> 
> 
>> Date: Fri, 14 Jan 2011 12:28:03 -0600
> 
>> From: Dan Letkeman <danletkeman at gmail.com>
> 
>> To: Phil Mayers <p.mayers at imperial.ac.uk>
> 
>> Cc: cisco-nsp at puck.nether.net
> 
>> Subject: Re: [c-nsp] Constant output drops on etherchannel
> 
>> Message-ID:
> 
>>            <AANLkTiktxHw2Za3yWjU4rmPaa3q_-EU7N_dKtxUgMaz=@mail.gmail.com>
> 
>> Content-Type: text/plain; charset=ISO-8859-1
> 
>> 
> 
>> 3560 or 3560G.
> 
>> 
> 
>> (C3560-IPSERVICESK9-M), Version 12.2(53)SE2
> 
>> 
> 
>> Interface config:
> 
>> 
> 
>> interface Port-channel2
> 
>> switchport trunk encapsulation dot1q
> 
>> switchport trunk native vlan 3009
> 
>> switchport trunk allowed vlan 8,10,1008,1101,3009  switchport mode trunk
> end
> 
>> 
> 
>> I see more output drops during higher traffic, but I still see drops during
> low traffic rates.  Always more on one interface.
> 
>> 
> 
>> I do have auto qos enabled for some of the phones I have connected to the
> switches, but I don't have any qos on the etherchannel trunks.
> 
>> 
> 
>> I'm just using the default etherchannel load balancing algorithm.
> 
>> 
> 
>> Thanks,
> 
>> Dan.
> 
> 
> 
> 
> 
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