[c-nsp] SPAN limitations on already-mirrored traffic

[Pierre Emeriaud]

2014-11-26 20:58 GMT+01:00 Some One <redacted at offlist>:
> Are you able to disable MAC learning on a VLAN on that switch? If you can
> then you can create a VLAN with 2 member ports and disable MAC Learning, any
> traffic coming in to that VLAN should be sent out of the other interface
> (same functionality as a hub).

Thanks, this is something I missed. I actually never used that feature before :)

I'll test this and report back.

> MAC learning can be disabled on 2960s but I've never worked with a 2970 so
> i'm not sure if it supports the command.
> http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_55_se/configuration/guide/scg_2960/swadmin.html#wp1268730

I don't have any 2960s handy, but iirc the 2970 is the L2-only version
of the 3560, feature-wise, so that might be feasible, if only the ios
is recent enough. I also have 3550-12T/G available easily, but it
might be just the same.

-pierre