[c-nsp] SPAN destination on oversubscribed module

[Andrew Miehs]

If this is for a permanent monitoring solution look at network taps from
someone like gigamon or netoptics. Save your SPAN ports for debugging
network issues - you can very easily overload line cards and fabric when
using SPAN.

Andrew



On Fri, Jan 10, 2014 at 2:14 AM, Lukas Tribus <luky-37 at hotmail.com> wrote:

> Hi,
>
> > Dears ,
> >
> > We have two 6509 interconnected via port-channel of two 10Ge port
> > carrying about 3Gb. the module used is WS-X6716-10T and only the
> > two mentioned port are used on this module for the moment . We are
> > now adding a monitoring probe that will be connected on this module,
> > the estimated monitored traffic is about 8Gb . Since this module has
> > an oversubscription rate of 4:1 , i need to check:
> >
> > * On witch port it is recommended to connect the new probe without
> >   affecting the port channel
> > * can one port on this module reach 8Gb of monitored traffic
> > * the monitored traffic will be added to the actual Swicth load or it
> >   is transparent ?
>
> I suggest you read [1], which explains everything. Enable performance mode
> if you are concerned about oversubscribtion or just make sure to only use
> one port per port-group.
>
> And yes, SPAN traffic has the same cost that normal traffic has.
>
>
>
> Regards,
>
> Lukas
>
>
> [1]
> http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/qa_cisco_catalyst_6500_series_16port_10gigabit_ethernet_module.html
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