VLAN

A VLAN (Virtual Local Area Network) creates a logical Layer 2 broadcast domain across compatible network equipment. It can separate users, voice, guests, management or devices without requiring a different physical switch for each group. VLANs organise traffic but do not automatically enforce security: communication between them depends on routing, firewall rules and access controls. Tags, native VLANs, trunks and allowed lists must agree across links, while endpoint ports normally use the intended access VLAN. Poor configuration can cause leakage, loops or loss of connectivity. Design should document identifiers, subnets, gateways, DHCP, ownership and permitted flows. Validation checks isolation and required communication from real ports and wireless networks. A VLAN diagram alone is insufficient unless switch configuration, routing and policy remain reconciled after changes.