---
id: 1778493954-IJHJ
aliases:
  - VLAN (Part 3)
tags: []
---

# VLAN (Part 3)

## Native VLAN on a router (ROAS)

There 2 methods for configuring the native VLAN on a router:

1.
```Cisco
R1(config)# int g0/0.10
R1(config-subif)#encapsulaton dot1q *vlan-id* native
```

2.
Configure the [[IP address]] for the native VLAN on the router's physical interface 
(the command is not necessary)
```Cisco
R1(config)# int g0/0.10
R1(config-subif)#ip address 192.168.1.62 255.255.255.192
```

## Layer 3 (Multilayer) switches

- A multilayer switch is capable of both switching and routing.
- It is '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 for 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

the command to enable Layer 3 routing on the switch is

```Cisco
SW2(config)#ip routing

## this configure the interface as a 'routed port'
## (Layer 3 port, not Layer 2 /switchport)
SW2(config)#interface g0/1
SW2(config-if)#no switchport

## then you can configure an IP address on the interface like a regular router interface
SW2(config-if)#ip address 192.168.1.193 255.255.255.252

## then you can configure the default route
SW2(config-if)#ip route 0.0.0.0 0.0.0.0 192.168.1.194
```

To configure SVI you can assign ip address to each vlan
```Cisco
SW2(config)#interface vlan10
SW2(config-if)#ip address 192.168.1.62 255.255.255.192
SW2(config-if)#no shutdown
SW2(config)#interface vlan20
SW2(config-if)#ip address 192.168.1.126 255.255.255.192
SW2(config-if)#no shutdown
SW2(config)#interface vlan30
SW2(config-if)#ip address 192.168.1.190 255.255.255.192
SW2(config-if)#no shutdown
```

1. The Vlan must exist on the switch
2. The swithc 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 an 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)

## Review

- Native VLAN on a router
- Wireshark analysis
- Layer 3 Switching/multilayer Switching

**next lesson**
- DTP (Dynamic Trunking Protocol)
- VTP (VLAN trunking Protocol)