Which Inter-VLAN Routing Method?

About this interactive

From the lesson: - **Legacy inter-VLAN routing:** one access port and one router interface per VLAN. Simple, but every VLAN costs a cable and a port at each end, and a bigger router as VLANs grow. - **Router-on-a-stick:** one 802.1Q trunk to the router, which splits it into a virtual interface (subinterface) per VLAN. Cheap on ports, but every routed flow shares that one link, which can saturate. - **Layer 3 switch:** a virtual router inside the switch routes between switch virtual interfaces (SVIs), one per VLAN. The usual choice for a decent-sized network; its drawback is cost.

What you'll learn

Tell legacy inter-VLAN routing, router-on-a-stick and Layer 3 switching apart from how each connects the VLANs to the router function
Weigh each method's cost: ports per VLAN for legacy routing, one shared link for router-on-a-stick, and a pricier switch for Layer 3 switching

Aligned to

Cisco CCNA

2.1 Configure and verify VLANs (normal range) spanning multiple switches

1.1 Explain the role and function of network components

Key terms

Inter-VLAN Routing: The process of forwarding traffic between two or more VLANs using a Layer 3 device, which is required because VLANs are separate broadcast domains and cannot communicate at Layer 2 alone. Inter-VLAN routing can be implemented using a physical router with a trunk link (router-on-a-stick), a multilayer switch with SVIs, or routed ports.
Router-on-a-Stick: An inter-VLAN routing design in which a single physical router interface is connected to a switch trunk and divided into subinterfaces, one per VLAN, each configured with 802.1Q encapsulation and the default gateway address for that VLAN's subnet.
Layer 3 Switch: A network switch that incorporates routing functionality, allowing it to forward traffic based on both MAC addresses and IP addresses across multiple networks.
Switch Virtual Interface: A virtual layer 3 interface on a switch associated with a VLAN. On a layer 2 switch a single SVI provides the management IP address; on a layer 3 switch, SVIs also route between VLANs.
Subinterface: A logical subdivision of a physical router interface that allows it to carry traffic for multiple VLANs, each assigned a unique VLAN ID and IP address.
VLAN Trunk: A point-to-point link between two switches that carries traffic for multiple VLANs simultaneously using IEEE 802.1Q tagging.

Topics

Inter Vlan Routing Router On A Stick Layer 3 Switch Svi Vlans Interactive Categorize

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