ACI hell part 1

When connecting access ports with static paths within an EPG that has trunking what a pain.

So basically if you have a static path binding using 802.1p then try and put an access port with 802.1p Access Untagged things may not work.

The reason is that the 802.1p Access Untagged setting it sets the vlan to 0 in the header, but it still has a vlan tag in there.  Some access devices don’t accept it because they are not  expecting a tag period.  This is especially meaningful with appliances.

If you set your mode to 802.1p Access Untagged and use the same Encapsulation VLAN tag as trunked ports, it will not work.  ACI will give you an error saying that you can’t have tagged and untagged in the same EPG.  Yet you can if you change the encapsulation VLAN ID to a different number it will work.

Remember that a VLAN in ACI is just bogus because ACI uses VXLAN, but endpoint devices care about that VLAN number.  Below is an example of 1 EPG with multiple endpoints in the same bridge domain with different VLAN encapsulations.

ACI8021P

 

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