Hi Markus,
You are right. We need something on ASW1 and ASW2 to make these loopback interfaces reachable. To make this work, we need to run a routing protocol and establish an OSPF neighbor adjacency in VLAN 10, 20, or 30 to advertise the loopback.
I’m making a change to the lab. We’ll add one more VLAN named “MANAGEMENT” that we can use for the L2 switches. We’ll establish OSPF neighbor adjacencies within this VLAN so that we can advertise the ASW1+ASW2 loopback interfaces.
Instead of OSPF, you could also configure a default gateway on ASW1+ASW2 but in that case, you’d have to use their VLAN 200 IP addresses for management since you can’t advertise the loopback interfaces.
Rene