SVI configuration (Cisco)

Technology: Network
Area: Networking General
Vendor: Cisco
Software: 12.X , 15.X
Platform: Catalyst 9200, Catalyst switches, Nexus Switches

A Switched Virtual Interface (SVI) is a routed interface in IOS representing the IP addressing space for a particular VLAN connected to this interface. 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.

With SVIs the switch will use a virtual Layer 3 interface to route traffic to other Layer 3 interfaces thus eliminating the need for a physical router. VLANs reduce the load on a network by dividing a LAN into smaller segments and keeping local traffic within a VLAN. However, because each VLAN has its own domain, a mechanism is needed for VLANs to pass data to other VLANs without passing the data through a router.

To configure the SVI, ensure your switch has a VLAN represented by the SVI you want to create:

Switch#vlan database
Switch(vlan)#vlan 2

Configuring the VLAN interfaces with the IP address:

Switch#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#interface Vlan2
Switch(config-if)#ip address 10.1.2.1 255.255.255.0
Switch(config-if)#no shutdown