"Advertised Externally" in BD vs EPG

[kumar.rb@cognizant.com]

Hello All - Configuring L3-OUT, so I have two questions. Can you help me, please

1) I wanted to advertise BD subnet to External Router using L3OUT, typically we enable "Advertised Externally" option under BD. I learned in one of the Cisco session is, the other way to advertise BD subnet is to enable "Advertised Externally option under EPG. Where to configure "Advertise Externally" under EPG using GUI?

2) In my existing configuration, we don't associate L3OUT under BD, but still, the Subnet getting advertised/Exported to an external device. How this is possible? Associating L3OUT in BD is a mandatory approach to get the subnet advertised from ACI to External device? Is there any other way to achieve without associating L3OUT under BD?

Thanks RB

[deepakba]

Hi Kumar,

First Answer:

The option is under - Tenenat -> AP -> EPG >Subnets >Double-click subent which you want to advertise externally and then check the box Advertise externally.

Second Answer:

You need to check what route you are advertising under option Aggregate Export/Import.If you advertising 0.0.0.0/0 it will advertise all the ACI fabric route to external device.

Thanks,

[kumar.rb@cognizant.com]

Thanks Deepak & McGarc for sharing the details. Much appreciated

[micgarc2 · Accepted solution]

My guess is that your setup is inter-VRF. The BD and L3 out are in different VRFs. With this setup you dont need to associate the L3 out to the BD because that is done through the global contract. If it was intra-VRF, this is required.