L3OUT Transfer Network with ACI

[Ulrich Vierkoetter]

Hello,

I have a question regarding the L2 behavior in L3OUT with SVIs in differnt Leafs.

Assuming have a /29 transfer Network distributed over 4 Devices:

One external Router/FW "R1" is connected single attached to one leaf "L1" and another Router "R2" is connected single attached to Leaf "L2".

L1 and L2 has SVI in same Encap Vlan and R1 and R2 ist attached to this Vlan with a routed port. So 4 IPs exist in the same Vlan within the L3OUT distributed over 2 (or maybe more Leafs).

In this case the R1 Router can ping R2 Router without any contract, correct ?

So, I mean the fabric builds an "implicit" Bridge Domain within this vlan and this L3OUT ?

What is the impact of changing the Leaf SVIs Vlan scope from "Local" to "VRF"  ?

Thanks in advance!

[6askorobogatov]

When you create 2 x L3out on 2 leafs (logical nodes)  with logical port with SVI  and overlapping subnets, you will have TWO not connected subnets on 2 leaf with overlapping IPs. 

[Sergiu.Daniluk · Accepted solution]

Hi @Ulrich Vierkoetter 

These images from ACI L3Out whitepaper might answer your questions:

1.Scenario 1: same encap on two different leaf switches, inside the same L3Out:

2. Scenario 2: Same encap on two different leaf switches, inside different l3Outs:

Best regards,

Sergiu

[Ulrich Vierkoetter]

Hi Sergiu,

this is very helpful to me. Thank you!

best regards,

Uli