Internal VLAN vs Front-panel (FD) VLAN - what's the difference?

[kamokoba]

Hello,

I noticed that any physical interface of a leaf switch is mapped both to an Internal VLAN and Front-panel (FD) VLAN.

What is the difference between them?

Initially I thought that perhaps Internal VLAN is a VLAN for an underlay network but when I issue "show vlan" command on a leaf switch I get the output indicating that such and such VLAN is mapped to a such and such EPG, so it's not a VLAN for underlay network then. (I know for sure that "show vlan" command when issued locally on the switch or via APIC will show only Internal VLANs)

Here is the screenshot showing Internal and Front-panel VLAN:

[luis_cordova]

Hi @kamokoba ,

Maybe this discussion can give you some guide:

https://community.cisco.com/t5/application-centric/types-of-vlan-information-found-in-cisco-aci/td-p/3009026

Regards

[micgarc2]

The FD-VLAN is the forwarding VLAN used to forward traffic. The FD_VLAN is used for EPGs. 

The BD vlan is not used for learning, only the EPG/encap/FD_VLAN 

• The BD will have its BD vlan and no encap vlan (vlan used on the front panel port going out)
• The EPG will have the FD_VLAN that maps to an encap vlan (vlan that you put on the wire).