Layer 3 (Multilayer) Switches

A multilayer switch is capable of both switching and routing.

It is a Layer 3 aware.

You can assign IP addresses to its interfaces, like a router.

You can create virtual interfaces for each VLAN, and assign IP addresses to those interfaces.

You can configure routes on it, just like a router.

It can be used fo inter-VLAN routing.

Inter-VLAN Routing via SVI

SVIs (Switch Virtual Interfaces) are the virtual interfaces you can assign IP addresses to in a multilayer switch.

Configure each PC to use the SVI (NOT the router) as their gateway address.

To send traffic to different subnets/VLANs, the PCs will send traffic to the switch, and the switch will route the traffic.

Switch Configuration

SVI Configuration

SVIs are shutdown by default, so remember to use no shutdown.

Requirements

1. The VLAN must already exist on the switch.

2. The switch must have at least one access port in the VLAN in an up/up state, AND/OR one trunk port that allows the VLAN that is in up/up state.

3. The VLAN must not be shutdown (you can use the shutdown command to disable a VLAN).

4. The SVI must not be shutdown (SVIs are disabled by default).