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cjrchoi11
Beginner

C200-M2, shared LOM, active-active w/etherchannel

Hi,

I configured Etherchannel for C200-M2 and CIMC shared LOM with the redundancy mode,

-active-active mode, when Etherchannel two switch ports UP, not reachable CIMC but okay ESXi and VMs. CIMC reachable if shutdown one of switch ports.

-active-standby mode, not a problem

Any idea why C200-M2 not reachable CIMC when the active-active redundancy mode?

Thanks in advance,

1 ACCEPTED SOLUTION

Accepted Solutions

Active/Active for the CIMC uses Adaptive Load Balancing for the NC-SI connection to the LOM ports and NOT LACP.  ALB allows for both ports to be active senders/receivers using their own MAC address and does not require any special configuration on the upstream switch(es).  If you enable this with connections to an actual port channel, the MAC address for each interface would be learned for the channel, but there is no guarantee that the return traffic would make it to the proper port.

The recommended CIMC redundancy mode to use in a case where you are port channeling for the OS would be  Active/Standby.  Active/Standby uses a common MAC address for a single NC-SI link active from the CIMC.  This way all traffic going to the CIMC would always be a common MAC and only one of the NC-SI ports on the LOM would be active.  This way the traffic will make it to the destination.

Steve McQuerry

UCS - Technical Marketing

View solution in original post

6 REPLIES 6

I haven't seen anything like you mentioned. Please make sure you have configured your CIMC as per the below link.

http://www.cisco.com/en/US/products/ps10493/products_configuration_example09186a0080b10d66.shtml

because the link just explaining the dedication mode which is not support failover scenario.

Anyone idea why not works active-active mode even okay with active-standy? BUG on C200-M2?

Thanks in advance,

Mason Tu
Beginner

Hi,

I got the same problem on C460M2.

If attach one LOM to Switch, both CIMC and ESXi are fine.

If attach two LOM to Switch with port-channel, CIMC failed but ESXi is fine.

I use Active-Active CIMC by the way.

Active/Active for the CIMC uses Adaptive Load Balancing for the NC-SI connection to the LOM ports and NOT LACP.  ALB allows for both ports to be active senders/receivers using their own MAC address and does not require any special configuration on the upstream switch(es).  If you enable this with connections to an actual port channel, the MAC address for each interface would be learned for the channel, but there is no guarantee that the return traffic would make it to the proper port.

The recommended CIMC redundancy mode to use in a case where you are port channeling for the OS would be  Active/Standby.  Active/Standby uses a common MAC address for a single NC-SI link active from the CIMC.  This way all traffic going to the CIMC would always be a common MAC and only one of the NC-SI ports on the LOM would be active.  This way the traffic will make it to the destination.

Steve McQuerry

UCS - Technical Marketing

View solution in original post

Hi could this be related to a similar issue discussed in this thread: https://supportforums.cisco.com/message/4041497#4041497

Etherchannel would not work due to the fact that vmk0 interface had picked up the same mac as the vNIC.

"If yes, the traffic flow could be running into defect CSCuf65032"

//

Yes! Thank you for this post. I was driving myself crazy trying to get active-active working with LACP and 2012 using Intel Pro Set software. Worked fine for the OS but not for CIMC and the only real solution and proper explanation is yours. Once I changed CIMC to Shared LOM/Active-Passive, everything started to work.

 

I think the term 'active/active' makes people think etherchannel or LACP. I couldn't find a single Cisco document that states that CIMC uses Adaptive Load Balancing and that LACP/etherchannel isn't best practise.

 

Thanks again.

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