Nexus 3064 Unicast Flooding

[MarkStites_2]

hi,

I have a Nexus 3064 which is not recording source MAC addresses after a successful ARP. The switch is then flooding the entire vlan with unicast traffic.

The config is a boring single VLAN. One port (48) is going to a 6509. Not as a trunk, just extending the VLAN. There are SVI's on both switches. the default route for the Nexus users is the 6509's IP.

The switch was basically, pulled out of the box, setup a single vlan(with jumbo frames) andan SVI, then plugged in the users. Nothing special.

Attached is the show tech support and the config.

Any ideas would be awesome,

thanks

Mark

[Reza Sharifi]

Hi,

If port 48 connects to the 6500 and the Nexus should be a layer-2 device only, then you need to change it from a routed port to a switch port with no ip.

interface Ethernet1/48

  description ES752A-9-1

  no cdp enable

  no switchport

  mtu 4174

  ip address 192.168.242.1/30

HTH

[MarkStites_2]

hi,

Thank you, woops sorry about that, that bit was changed at the last moment.( I just returned from a trip where the other engineers were troubleshooting this.) Originally, port 48 was simply in VLAN 323.

This change did not seem to correct the unicast flooding as we're still suffering from it.

thanks

Mark

[Peter Phaal]

Mark,

I don't have the answer, but you might find the problem easier to troubleshoot if you turn on sFlow monitoring on your Nexus 3064 so you can visualize the traffic, see http://blog.sflow.com/2012/08/cisco-adds-sflow-support.html

Peter