[j-nsp] VXLAN multi-site solution problem

[niklas rehnberg]

Hi all,

I have two DCs that work as multi-site , IE all subnets are available in
both DCs.
Using spine/leaf setup, two spines (QFX10000) on each site.
Using the Central GW setup, the spines are L3 GWs.
In the overlay BGP a filter has been included so the leafs see only their
own site spines, and will result in the traffic always using the nearest
spine to reach the WAN.
A design problem I have found now is if the return traffic to a leaf in
site1 comes via site2 spines.
The spine in site2 will add a vxlan header and send it leaf in site1, but
the leaf will drop the traffic as the spine is unknown (as I have designed
the solution).

I need suggestions on how to solve this.
A very easy way is to remove the filter so all leafs see all spine, but the
drawback will be that a leaf in site1 can use a spine in site2 as L3 GW.
Cisco has a solution called "VXLAN EVPN Multi-Site Design", I have not seen
any simulare example for juniper.

Thanks Niklas