Glossary

VLAN

A VLAN (Virtual Local Area Network) is a logical segmentation of a physical network, defined by IEEE 802.1Q, that isolates groups of devices - such as guest WiFi users and staff systems - from each other while sharing the same switches and cables.

A VLAN (Virtual Local Area Network) is a way of splitting one physical network into several isolated logical networks. Devices on different VLANs cannot talk to each other unless a router or firewall explicitly allows it, even though they share the same switches and cabling. VLANs are defined by the IEEE 802.1Q standard, which adds a small tag carrying a VLAN ID (1 to 4094) to each Ethernet frame so switches know which virtual network the traffic belongs to.

Why guest WiFi gets its own VLAN

Guest devices are unknown and untrusted. Putting them on the same network as card terminals, CCTV, or the office PC gives any compromised phone a path into systems that matter. A dedicated guest VLAN, firewalled to reach only the internet, removes that path entirely - and keeps guest traffic out of PCI DSS scope for the payment network. This is why every serious guest WiFi deployment separates guest and staff at the VLAN level, not just with different passwords.

How it is set up

  1. Each SSID on the access point is mapped to a VLAN ID (for example, guest SSID to VLAN 40).
  2. Switch ports carrying multiple VLANs are configured as trunk (tagged) ports.
  3. The router or firewall gives each VLAN its own subnet and DHCP range, and rules block guest-to-staff traffic.
  4. Client isolation is usually enabled on the guest VLAN so guest devices cannot see each other either.

A typical venue layout

  • VLAN 10 - management (access points, switches, controller).
  • VLAN 20 - staff devices and back office.
  • VLAN 30 - POS and payment terminals.
  • VLAN 40 - guest WiFi, internet-only, client isolation on.
Related

Related terms

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