I'm having a following topology
Could this be achieved? I've configured this network, but routing between the two VLAN-s are not working. Using Ubiquity Edge X routers.
Could this be archived with any mid-range or above mid-range routers or having any idea what I''m doing wrong?
You cannot run IPsec tunnel ends over a load balancer.
If you want load balancing in VPN you'll need to create two tunnels and then balance between them (e.g. using ECMP).
VLANs are layer 2 configuration and you cannot run it in a layer 3. If you want communicate VLAN over Layer 3. We can Use QnQ, VXLAN or BGP EVPN. Then You can load balance as well.
Looking at this, it doesn't seem like balancing between links is what you would want to do. You would be better off building two tunnels and balancing between them. This would give you future flexibility for an SD-WAN type control over two different circuits. If you are doing a load balance, you would have to re-configure this later on and ultimately re-architect this if you moved say Eth4 to a different provider to mitigate unreliable consistency.
To answer the question, you could use a load balancer that keep track of the health of the endpoints its balancing to and will always balance to from one device to the VPN server to the same node (provided that it is healthy). Alternatively, you could have the box check into a VPN registry that keeps track of healthy VPN endpoint and return the server to connect to. Both of these options are not great and its easier and more flexible to create two tunnels and balance between them(as shown above).
