Question on SPAN with Dual-Homed FEX

[Ryan Curry]

Hi All, I've got a need to SPAN a port from one of our Nexus 2Ks but am at a loss on how/where to destine the traffic.  All of our Nexus 2Ks (both 2148s and 2248s) are dual-homed back to a pair of Nexus 5020s.  I need to forward the traffic to a copper port, but it appears that I can't use any of the Nexus 2K ports as a destination (when I try to set the interface to switchport monitor I get the error "switchport monitor not supported for interface type") and the 5020's won't support a GLCT.  Also, we're currently running version 5.0(2)N1(1).

From what I can see, my only other option is to try using ER-SPAN.

Any help or clarification is appreciated.

[Prashanth Krishnappa · Accepted solution]

Nexus 5020s will accept GLC-T but 1G ports are only supported in the first 16 ports of a 5020(and first 8 ports of a 5010). You will also need to configure "speed 1000" under the interface.

Also, note that if you SPAN a dual homed FEX interface, you will need to configure SPAN on both parent switches if you want to see complete traffic since it could get hashed to either of the N5ks. Alternatively you could shut down the FEX fabric interfaces on one Nexus 5k.

[Ryan Curry]

Thanks prkrishn, I changed the port to speed 1000 and found it worked.  It's the little (overlooked) details that make it work.  Thanks the help!