[c-nsp] 20G Port-Channel Drops

[Stig Johansen]

Albert Goerend wrote:
>On Wed, Mar 10, 2010 at 11:01 PM, James Slepicka <cisco-nsp at slepicka.net> wrote:
>> I've seen similar behavior when spanning a vlan that runs across a 10gb
>> port/port-channel to a 1Gb interface (e.g., monitor session 1 source vlan
>> 10, monitor session 1 destination int gi1/1).

>Ouch! Is this a bug or a feature?
>What would be the workaround?

Maybe VACL could be an alternative for you?

I have noticed this passage in before when researching the possibilities concerning alternatives to using monitor-sessions before:

(from http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a0080883ca2.shtml#adv)

There are several limitations of VSPAN usage for traffic analysis:

[..snip..]

A destination port receives copies of sent and received traffic for all monitored source ports. If a destination port is oversubscribed, it can become congested. This congestion can affect traffic forwarding on one or more of the source ports.

Could be this "feature" you are running into.

/Stig