APIC: APIC doesn’t find the Leaf Switches

There can be a nasty little problem (you might want to call it bug) that prevents the APIC from discovering the connected Nexus Leaf Switches.

The reason behind it is that after an CIMC Update and/or wipe of the CIMC it can happen that LLDP is enabled on the VIC Card. The problem here is that if it is enabled on the VIC, the LLDP messages get intercepted by the Firmware on the VIC and never reach the APIC Software. So the APIC can’t discover the Leaf’s.

Here’s how to verify this:

No LLDP Neighbors seen from the Leafs:

Leaf101# show lldp neighbors 
Capability codes:
  (R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
  (W) WLAN Access Point, (P) Repeater, (S) Station, (O) Other
Device ID            Local Intf      Hold-time  Capability  Port ID  

Total entries displayed: 0


Log on via ssh to the CIMC:

C220-FCHXXXXXXXX# scope chassis

C220-FCHXXXXXXXX /chassis # show adapter 
PCI Slot Product Name   Serial Number  Product ID     Vendor               
-------- -------------- -------------- -------------- -------------------- 
1        UCS VIC 1225   FCHYYYYYYYY    UCSC-PCIE-C... Cisco Systems Inc    

C220-FCHXXXXXXXX /chassis #  scope adapter 1

C220-FCHXXXXXXXX /chassis/adapter # show detail | grep LLDP
    LLDP: Enabled
C220-FCHXXXXXXXX /chassis/adapter # set lldp disabled

C220-FCHXXXXXXXX /chassis/adapter # commit

Afterwards you power cycle the Server.

Verification that LLDP is no disabled on the VIC:

C220-FCHXXXXXXXX# scope chassis 

C220-FCHXXXXXXXX /chassis # scope adapter 1

C220-FCHXXXXXXXX /chassis/adapter #  show detail | grep LLDP
    LLDP: Disabled
C220-FCHXXXXXXXX /chassis/adapter #



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2 Thoughts to “APIC: APIC doesn’t find the Leaf Switches”

  1. Jakub Horbacewicz

    Also, a useful command on the APIC in regards to troubleshooting LLDP/discovery issue is: acidiag run lldptool [in/out] eth2-[1/2]

    1. Thx for the Info Jakub!

      The command is really usefull! I’ll add it to the post!

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