[c-nsp] How to find the root cause of packet loss

[Peter Rathlev]

On Fri, 2010-06-18 at 14:56 +0300, Anton Turygin wrote:
> Getting output drops and packet loss on Catalyst WS-C2960G-48TC-L.

Someone should start selling T-shirts with a pun on that. :-)

> The traffic is relatevely small but output drops are growing hundreds per 
> second.
> 
> GigabitEthernet0/45 is up, line protocol is up (connected)
[...]
>    Input queue: 0/4096/0/0 (size/max/drops/flushes); Total output drops: 32013814
>    Queueing strategy: fifo
>    Output queue: 0/4096 (size/max)
>    5 minute input rate 57250000 bits/sec, 33933 packets/sec
>    5 minute output rate 480872000 bits/sec, 47800 packets/sec
[...]

The problem is probably "micro-bursts", which the 2960 is exceptionally
bad at handling.

You can adjust some of the SRR queueing parameters. Look in the list
archive for details on the 3560, which has similar problems that have
been discussed extensively.

Or get another switch. :-)

-- 
Peter