In a recent project, I had the opportunity to work with something “new” yet familiar. During a customer data center refresh project, one of the key tasks was upgrading their aging Nexus 5000 to the new Nexus 9000 series.

The model in play? N93360YC-FX2, a powerhouse with enhanced capabilities — but with a few nuances.

At first glance, porting over configurations from the N5K seemed straightforward.
No FCoE, no zoning, no fancy storage integrations.

But then came the surprise.

While copying over configurations, I encountered an unexpected error related to TCAM, specifically that the:

“vacl region is not configured.”

This caused several issues:

  • vPC was up, but no active VLANs appeared on the trunk
  • Interface trunk showed error-disabled for all VLANs

After some research — and input from my Cisco Champion network — it became clear that the Nexus 9000 requires explicit TCAM vacl region configuration for:

  • ACLs within VLAN maps
  • ACLs under a port-channel for HSRP filtering

What is TCAM?

Ternary Content Addressable Memory (TCAM) is specialized high-speed lookup memory used in switches and routers.

It’s commonly used for:

  • ACLs
  • QoS
  • Route lookups
  • Policy enforcement

TCAM’s ability to match 0 / 1 / don’t care makes it powerful for complex packet classification.

On the N93360YC-FX2, the default TCAM partition had not allocated a VACL region — causing the configuration import error and the resulting trunk failure.

The Fix: Reconfigure TCAM Regions

To resolve the issue, TCAM space needed to be explicitly defined.

The following configuration worked:

switch(config)# hardware access-list tcam region egr-racl 1280
switch(config)# hardware access-list tcam region ing-racl 2048
    (Reboot required)

switch(config)# hardware access-list tcam region vacl 256
    (Reboot required)