Routed Interfaces on Layer-3 Switches and Internal VLANs
In the Router Interfaces and Switch Ports blog post, I described why we have switch ports and routed interfaces on layer-3 switches. Another blog post in the same series described the conceptual architecture of a layer-3 switch:
- All interfaces are connected to a VLAN-aware switch
- The switch interfaces could be access or trunk interfaces1.
- Each VLAN in a VLAN-aware switch can be connected to an internal router through a VLAN interface.
However, that’s not how we configure layer-3 switches. There’s a significant gap between the conceptual configuration model and the internal architecture: