10G switch drops traffic for a split second

Tomi Hakala tomi.hakala at pobox.fi
Tue Nov 29 17:06:26 UTC 2016

If you have congestion on outgoing interfaces you are most likely 
running out of packet buffer space on your switch. Especially campus 
class switches have small buffers, 4 MB or so and it can run out during 
high bursts and interface congestion. With some switches you could 
alleviate problem by rearranging congested interfaces to ports with 
seperate buffer pool, but you have to check with your switch vendor or 
documentation if your switches have shared or split buffer pools. Or 
just replace your switches with ones having deeper buffers.


On 29.11.2016 11.06, TJ Trout wrote:
> I recently upgraded my core network from 1G to 10G and after the upgrade I
> have noticed that my 10G switch during peak traffic (1500mbps, 100,000pps)
> seems to be dropping traffic for a split second across all ports and all
> vlans. I immediately replaced the switch with a different brand/model and
> the problem persists.
> Sometimes traffic drops to zero, others it drops to 50%, problem is very
> random but seems to occur with much more frequency during high PPS (pushing
> high traffic / iperf does not induce problem)
> Could this be MTU? I've tried flow control, hard code duplex, stp on/off etc
> I'm at a loss any ideas?
> TJ Trout
> Volt Broadband

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