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Layer 3 Switching (SVI) for Inter-VLAN Routing

CCNA: 0 to Hero - Comprehensive Network Engineering Bootcamp

Lesson 28: Layer 3 Switching (SVI)

In larger, modern enterprise networks, multi-layer (Layer 3) switches handle inter-VLAN routing, offering much higher speed and efficiency than RoaS.

Switched Virtual Interface (SVI)

A Layer 3 switch creates a Switched Virtual Interface (SVI), which is a virtual interface associated with a specific VLAN. The SVI acts as the default gateway for that VLAN.

Advantages over RoaS:

  • Speed: Routing happens in hardware (ASICs) rather than software, providing wire-speed routing.
  • Simplicity: No need for trunk links to external routers.

SVI Configuration Steps

  1. Enable Routing (Globally): Layer 3 routing is often disabled by default on switches.
  2. Create the SVI: Assign an IP address to the SVI.

ios Switch# configure terminal Switch(config)# ip routing

! Create VLAN 10 and assign the gateway IP Switch(config)# interface vlan 10 Switch(config-if)# ip address 192.168.10.1 255.255.255.0 Switch(config-if)# no shutdown

! Note: If you want to use the switch for remote management, you must configure a default gateway for the switch itself. Switch(config)# ip default-gateway 192.168.1.254