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SD Access - Is there an L2 VNI in SD Access VxLAN?

muthumohan
Beginner
Beginner

The ENCOR training guide says, " The VXLAN VNID is used to provide both Layer 2 (Layer 2 VNID) and Layer 3 (Layer 3 VNID) segmentation"
 
In SD Access, we are mapping VNs to VNIs. (We are not mapping VLANs to VNIs)
 
So, in SDA, where is this Layer 2 VNI coming from? My understanding is, there is no Layer 2 VNID in SDA.
 
Also, if the traffic is routed from one subnet 10.1.1.0/24 to another subnet 10.2.2.0/24 (within the same VN), the VXLAN encapsulation would be IP-in-IP, right?
If traffic is switched within the same subnet 10.3.3.0/24, but across two switches, the VXLAN encapsulation would be MAC-in-IP, right?

 

Would appreciate any clarity on this.

 
Thanks!!!

1 Reply 1

Flavio Miranda
Advisor
Advisor

  What makes it complicate is that in Software Defined network like SDA, they took the current network and call it underlay and then, using software, they build a upper  layer they call Overlay. At the end, this is all the old and good TCP/IP over Ethernet but this overlay layer makes it confusing.

 

 "So, in SDA, where is this Layer 2 VNI coming from? My understanding is, there is no Layer 2 VNID in SDA."

Yes, in fact there is, althouth is not mandatory. Take a look on the picture I attached. It show perfectly well how this is done.

 

"Also, if the traffic is routed from one subnet 10.1.1.0/24 to another subnet 10.2.2.0/24 (within the same VN), the VXLAN encapsulation would be IP-in-IP, right?
If traffic is switched within the same subnet 10.3.3.0/24, but across two switches, the VXLAN encapsulation would be MAC-in-IP, right?"

 

 Keep in mind that inside the fabric is like we have only on switch and the encapsulation is always over IP. Take a look on the picture attached again.

 

 

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