InterVLANtrafik

InterVLANtrafik refers to the traffic that moves between devices located on different VLANs within a local network. Because VLANs segment broadcast domains at Layer 2, devices in separate VLANs cannot communicate directly without a Layer 3 device performing inter-VLAN routing. The term reflects the common network engineering practice of routing between VLANs.

Inter-VLAN routing is achieved by a routed interface between VLANs on a Layer 3 capable device. Common approaches are router-on-a-stick, where a router uses subinterfaces with 802.1Q tagging on a single trunk link to multiple VLANs, and Layer 3 switches that provide SVIs (Switch Virtual Interfaces) per VLAN and run IP routing to forward traffic between VLANs. In larger networks, a dedicated router or firewall is often connected to the switch for centralized policy enforcement.

Typical setup steps include defining the VLANs on the switch, assigning access ports to the appropriate VLANs, configuring a trunk between the switch and the Layer 3 device, creating SVIs or routing interfaces for each VLAN, and assigning IP addresses as the default gateways for hosts in those VLANs. DHCP can be provided within each VLAN or relayed to a central DHCP server. Access control lists or firewall rules may be used to regulate inter-VLAN traffic and protect sensitive segments.

Common issues include misconfigured trunks, incorrect VLAN tagging, or missing IP routing. Performance considerations involve the capacity of the inter-VLAN path; in high-traffic environments, a multilayer switch is often preferred over router-on-a-stick to reduce latency and improve throughput.