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Nexus 7700 errors cts


Hello,  we are doing macsec betwwen two Nexus 7700 switches and get an error message when applying the command "sh cts internal event-history errors":

593) Event:E_DEBUG, length:155, at 355756 usecs after Tue May 9 08:28:09 2023
[105] Failed to update MAC DB for VLAN: 80, MAC: e884.a58b.775b, error: Cannot add this MAC entry since max. # of MAC entries supported by CTS has reached.

Has somebody seen this? We do not have a lot of MAC addresses on this particular VLAN.

1 Reply 1


Hello maraz,

I just believe that may be your help. The error message you encountered on your Nexus 7700 switch indicates that the maximum number of MAC entries supported by the Cisco TrustSec (CTS) feature has been reached for VLAN 80. This error can occur even if there aren't many MAC addresses present in that specific VLAN.

To troubleshoot and resolve this issue, you can try the following steps:

  1. Verify the MAC address limit: Check the maximum number of MAC addresses supported by the Nexus 7700 switch and ensure it aligns with your network requirements. Depending on the model and software version, there may be specific limitations on the number of MAC addresses supported by CTS.

  2. Review MAC address usage: Examine the MAC address usage on VLAN 80 by using the command "show mac address-table vlan 80" or similar variations. Verify if there are any unexpected or excessive MAC addresses present.

  3. Clear MAC addresses: If there are any stale or unnecessary MAC addresses in the MAC address table, you can clear them using the "clear mac address-table dynamic" command. This step can free up space for new MAC addresses to be added.

  4. Increase MAC address limit: If you determine that the current MAC address limit is insufficient for your network needs, you may need to consider increasing the MAC address limit on the Nexus 7700 switch. Refer to Cisco's documentation or consult with Cisco support for guidance on how to adjust the MAC address limit.

  5. Upgrade software version: If you're running an older software version on the Nexus 7700 switch, consider upgrading to a newer release. Software updates often include bug fixes, performance improvements, and enhancements to various features, including MAC address management.

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