[c-nsp] Need help w/ output drops on 7613 WS-X6748-GE-TX

[Peter Rathlev]

On Wed, 2011-01-05 at 11:36 +0200, Hank Nussbacher wrote:
> We have a 7613 w/ WS-SUP720-3BXL running 12.2(18)SXF11.
> We have a 48 port WS-X6748-GE-TX.  On one interface we
> continue to see output drops when traffic goes above 200Mb/sec.
[snip]

Do you have QoS enabled? What does "show queueing interface Gi9/29" tell
you?

Output drops are "egress buffer overflow" drops, so technically it
happens because the box tries to send a packet out an interface already
in use (transmitting another packet) when there is no buffer space to
store the packet until transmission. Micro-bursts and oversubscription
are possible causes. Short queues exacerbate the problem. With "mls qos"
enabled and no interface-specific adjustments you could have (too) short
queues for the relevant traffic.

-- 
Peter