APIC error logs

[Thiyagarajan K]

Hello Guys,

I'm finding the below error log in our APIC and we are finding frequent drops for the end points of the EPG for which we are seeing the error log.

Configuration failed for uni/tn-TN-IT-NPC01/ap-AP-IT-NPC01-01/epg-EP-NPC01-ISC101 node 154 VPC-Profile-01 due to Encap Already Used in Another EPG

Could you please help me on few steps to troubleshoot this issue?

Regards,

Thiyagu

[Tomas de Leon]

Take a look at:

Unicast Data Plane Forwarding and Reachability
http://aci-troubleshooting-book.readthedocs.io/en/latest/unicast.html

Chapter: Fabric Connectivity
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/1-x/Operating_ACI/guide/b_Cisco_Operating_ACI/b_Cisco_Operating_ACI_chapter_0110.html

This error could be associated with VLAN Allocation and overlapping VLANs in different pools. Please check your VLAN pools to see if you have different domains using different vlan pools with overlapping vlans.

Thanks again for using the Cisco Support Community for ACI!

T.

[Jenny Ngo]

You usually get the fault saying "Encap Already Used in Another EPG" when you add a static binding in EPG B with a encap VLAN that is already used in another static binding on EPG A.

Check other EPGs if you've already used the encap VLAN on another EPG.

If you have many EPGs, you can quickly find the other EPG using the encap VLAN by using these commands on the switch:

leaf# show vlan extended | grep vlan-999    <--  encap VLAN you are attempting to use
 23   enet  CE         vlan-999

leaf# show vlan id 23 extended
 VLAN Name                             Status    Ports
 ---- -------------------------------- --------- -------------------------------
 23   JN-2:JN-AP2:JN-EPG4              active    Eth1/5, Eth1/15     <-- EPG using the encap VLAN

 VLAN Type  Vlan-mode  Encap
 ---- ----- ---------- -------------------------------
 23   enet  CE         vlan-999

You have a few options after that, but the easiest would be to use another encap VLAN that you aren't already using for another EPG.

Also, it is expected that when you have this fault in an EPG, the endpoint attached to this interface showing on this fault will most likely experience dropped traffic as the interface hasn't been correctly configured for this endpoint.