[c-nsp] 20G Port-Channel Drops

[Phil Mayers]

On 03/10/2010 10:23 PM, Albert Goerend wrote:
> On Wed, Mar 10, 2010 at 11:04 PM, Albert Goerend
> <albert.goerend at gmail.com>  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?
>>
>
> Quick follow-up:
>
> I have a monitor session on a 1G port listening to vlan2, because I
> need to detect new mac addresses with arpwatch and solve possible
> conflicts if two customers suddenly use the same IP address.
> I turned off the monitoring session, and the port-channel is running fine!
>
> I still need something to listen in vlan2 - what workaround can be done?

Ask the router for the ARP table, via SNMP or CLI (big arp tables are 
slow over SNMP on 6500s because of the sorting that has to go on - we 
fetch ours over SSH+Expect sessions).