How to Configure Switch Virtual Interface (SVI) as a Layer 3 Interface on Cisco Switch

A Switched Virtual Interface (SVI) is a VLAN of switch ports represented by one interface to a routing or bridging system. There is no physical interface for the VLAN and the SVI provides the Layer 3 processing for packets from all switch ports associated with the VLAN.

SVIs are generally configured for a VLAN for the following reasons:

• Allow traffic to be routed between VLANs by providing a default gateway for the VLAN.
• Provide Layer 3 IP connectivity to the switch.
• Support bridging configurations and routing protocol.

SVIs advantages include:

• Much faster than router on a stick, because everything is hardware-switched and routed.
• No need for external links from the switch to the router for routing.
• Latency is much lower because it does not need to leave the switch.
   

To configure Switch Virtual Interface (SVI) I will use IOSv-L2 on EVE-NG. How to configure IOSv-L2 on GNS3 for advanced Switching.

TASK

• Create VLANs 10, 20, 30 and 20

• Configure all IP addresses as specified.

  SW1: VLAN-10 - 192.168.10.1/24, VLAN-20 - 192.168.20.1/24, VLAN-30 - 192.168.30.1/24, VLAN-40 - 192.168.40.1/24,

  SW2: VLAN-10 - 192.168.10.2/24

  SW3: VLAN-10 - 192.168.10.3/24

• Configure SW1 SVI Interface for all the VLANs and configure IP address.
• Configure PC1 in VLAN 20 and PC2 in VLAN 30.
• Ensure PC1 and PC2 are able to communicate with each other.

Topology for this Task

Create VLANs on all switches

SW1(config)#vlan 10
SW1(config-vlan)#name Management
SW1(config-vlan)#exit
SW1(config)#vlan 20
SW1(config-vlan)#name Admin
SW1(config)#vlan 30
SW1(config-vlan)#name IT
SW1(config)#vlan 40
SW1(config-vlan)#name Accounts
SW1(config-vlan)#exit

Create SVI Interfaces on SW1

SW1(config)#interface vlan 10
SW1(config-if)#ip address 192.168.10.1 255.255.255.0
SW1(config-if)#no shutdown
SW1(config-if)#interface vlan 20
SW1(config-if)#ip address 192.168.20.1 255.255.255.0
SW1(config-if)#no shutdown
SW1(config-if)#ip address 192.168.30.1 255.255.255.0
SW1(config-if)#no shutdown
SW1(config-if)#interface vlan 20
SW1(config-if)#ip address 192.168.40.1 255.255.255.0
SW1(config-if)#no shutdown

Make all Switch to Switch link Trunk as on Topology Example below

SW(config)#interface gigabitEthernet <inteface no>
SW(config-if)#switchport trunk encapsulation dot1q
SW(config-if)#switchport mode trunk
SW(config-if)#no shutdown

Make Members of VLANs PC1 and PC2

SW2(config)#interface gigabitEthernet 0/2
SW2(config-if)#switchport mode access
SW2(config-if)#switchport access vlan 20
SW2(config-if)# no shutdown

SW3(config)#interface gigabitEthernet 0/2
SW3(config-if)#switchport mode access
SW3(config-if)#switchport access vlan 30
SW3(config-if)# no shutdown

Create SVI Interfaces on SW2 and SW3 for VLAN-10 only.

SW2

SW2(config)#interface vlan 10
SW2(config-if)#ip address 192.168.10.2 255.255.255.0
SW2(config-if)#no shutdown

SW3

SW2(config)#interface vlan 10
SW2(config-if)#ip address 192.168.10.3 255.255.255.0
SW2(config-if)#no shutdown

Create a default route on SW2 and SW3 pointing to SW1 VLAN 10 SVI interface so that both the switched can forward traffic coming from any VLANs.

SW(config)#ip default-gateway 192.168.10.1

Configure PC1 and PC 2 Ip addresses

PC1> ip 192.168.10.2/24 192.168.10.1
PC2> ip 192.168.20.2/24 192.168.20.1

Check connectivity

Congratulations: You have configured SVI successfully.