CISCO ACI learning duplicate MAC(Alteon LB-interface) for multiple IP

[shailendra harinkhede]

Design: ACI to physical Alteon LB connected over VPC 

VPC -Port-channel feature: PCP-ON  

Control : Fast select hot standby port, Graceful convergence, Suspend individual port 

Could you please let me know how we can avoid causing a MAC to corrupt the ARP table of ACI? 

Observation during the fault troubleshooting

1. Checked MAC address 00:03:B2:D3:04:05, found many faults in EPG-DEV for LB1 MAC address, and it was used for advertising many physical servers IPS in this EPG and causing conflict, for example:

10.10.0.88 / 00:50:56:81:66:3C

10.10.4.2 / 00:50:56:A3:E2:A4

1. Both were advertised using MAC 00:03:B2:D3:04:05 as well
2. Affected server's on 3/19 issue were on different vADC's
3. We unshut LB1 ports, issue not observed

Update from RADWARE  Alteon TAC:

1. No issue observed on any vADC and VX during the issue

[Sergiu.Daniluk]

Hi @shailendra harinkhede 

You need to give us more details about the problem you are facing.

From what I understand so far, you see duplicate MAC faults for IP addresses 10.10.0.88 and 10.10.4.2, right? This basically means that these IP addresses are "seen" by the ACI Fabric using multiple MAC addresses, the real one and the LB's MAC.

You have to see how and why there is traffic generated by LB, for that Source IPs. It could be something expected (doing some IP sync using ARPs, similar with how Checkpoint is doing).

I would suggest you verify this: what traffic is being sourced by LB using SMAC it's own MAC and SIP the affected IPs.

Depending on the results you should take different directions to investigate.

Stay safe,

Sergiu