Packet loss when pinging through ACI

[Arthur Martin]

Hi community,

I'm currently starting with ACI and the whole Application Centric concept is fairly new to me so I use the time to get familiar with ACI in our lab.

I created the following physical setup (no redundant paths):

... and configured the following logical setup to get some experience with L2out:

Using now Cisco IOS pings from either of the devices (4506 switch or the 2911 router) to the according other device results in irregular packet losses :-(

The funny thing is when instead of L2out I just extend the EPG using static ports all works 100%

Anyone have same experience with this as well or maybe even a solution?

Thanks in advance!

Arthur

[Ulrich Hansen]

Hi Arthur,

I've experienced a similar issue. My setup is slightly different in that it involves FEX'es. But I experienced intermittent packet loss and complete loss, which looked like some kind of routing issue.

When ever my DGW was located outside the fabric by extended the EPG to an external router, everything worked flawlessly. Initially I suspected that the problem reappeared whenever I enabled ucast-routing on the BD, but even when I did that and still retained the DGW on the external router, it still worked.

Eventually I looked deeper at the L3out and noticed a very odd BGP peering issue. After looking deeper into it and still unable to determine the root cause, I wiped the L3out config and re-configured it. And that did the trick. Since then I have not seen any problems.

How is your L3out configured?

/Ulrich