VLAN — Virtual Local Area Network
Definition
A VLAN (virtual local area network) is a logical partition of a physical Ethernet network, defined by IEEE 802.1Q, that isolates traffic as if it ran on separate switches. Each tagged frame carries a VLAN identifier of 12 bits, which allows up to 4094 usable VLANs. In AV systems, VLANs commonly separate audio (Dante, AES67), video (NDI), lighting (sACN, Art-Net), control and guest traffic, so that broadcast and flooded multicast in one domain do not reach the others. Traffic passes from one VLAN to another only through a router or a layer 3 switch. VLANs require managed switches.
In the field
Running Dante and NDI on separate VLANs keeps bursts of video traffic and flooded multicast away from the ports that carry audio. The Dante network design guide published by Audinate and Yamaha describes VLANs as a way to separate Dante from other traffic on a shared switch.
Related lessons
Sources
- IEEE 802.1Q (Wikipedia, pointeur secondaire) : VID sur 12 bits, valeurs 0 et 4095 réservées, 4094 VLAN utilisables · en.wikipedia.org
- Audinate/Yamaha, Dante Network Design Guide, VLAN : séparation du trafic Dante par VLAN sur un switch partagé · usa.yamaha.com
- RFC 4541 : sans IGMP snooping, le multicast est relayé sur toutes les interfaces · rfc-editor.org