[c-nsp] Ouput Drops - 6500...

[Jon Lewis]

On Wed, 2 Nov 2005, Church, Chuck wrote:

> Are the drops on a physical interface, or a VLAN int?  If you're trying
> to put all 700mbit/sec (which is an average) out on one physical
> interface, there a good chance there are frequent bursts above 700mbit,
> maybe even approaching the 1gig limit.  Those gig ports only have a
> small (~1 mbyte or so) buffer, so they don't queue stuff for too long.
> Those bursts are probably the cause.

I'm seeing similar output drops on 6509s (WS-X6348-RJ-45 FE ports), some 
on interfaces that only do about 30-40mbit/s.  The drops show up on 
physical interface counters, not on the vlan interface, though I don't 
think the vlan interface has such a counter.  At least

#sh int vlan 1110 counters errors
Counters information is not available for Vlan1110

The worst one at the moment is an FE that gets up to around 60mbit/s 
output.  It's got about 0.2% of its output packets being dropped.  Is this 
a limitation caused by the small per-port buffers on older 6509 ethernet 
blades?

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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