VLAN Configuration for AV Networks

A VLAN (Virtual Local Area Network) is a logical partition within a physical Ethernet switch that isolates traffic into separate broadcast domains. For AV systems, VLANs serve two critical functions: they protect real-time AV streams from interference by office traffic, and they simplify qos-for-audio implementation by grouping all audio/video onto a single tagged segment.

Why VLANs Matter for AV

Isolation — Office users browsing the web or syncing cloud storage won't compete with audio and video packets for bandwidth.

QoS Simplification — You can apply aggressive prioritization to the AV VLAN without affecting office productivity.

Security — Restrict VLAN membership to authorized AV devices, preventing rogue access to audio/video distribution.

Scalability — Support multiple isolated AV systems (conference room, theater, house system) without physical rewiring.

IT Collaboration — Network administrators understand VLANs; configuring one for AV is more palatable than demanding dedicated switches.

Basic VLAN Concepts

Switches have physical ports. A VLAN assigns ports to logical groups. For example:

• VLAN 1 (default) — office computers, printers, phones
• VLAN 100 — AV distribution (Dante devices, codec, amps)
• VLAN 200 — meeting room displays and input devices

The switch carries traffic tagged with VLAN IDs (802.1Q tags) between ports. Devices on one VLAN don't see broadcast traffic from another unless explicitly allowed via routing.

Designing an AV VLAN

Membership — Include all real-time AV devices: Dante nodes, DSP processors, video encoders/decoders, control processors. Exclude general office devices.

Tagging — Ports carrying AV VLAN traffic must be set to "tagged" mode (also called "trunk" ports). Ports connecting individual devices (console, amp) can be "untagged" with the AV VLAN as native VLAN.

IP Addressing — Assign the AV VLAN its own subnet, e.g., 192.168.100.0/24. This prevents IP conflicts and helps network admins understand traffic flow.

Gateway — AV VLANs need a gateway (router/layer-3 switch) if devices need to communicate outside the VLAN, such as a Dante Controller on the office network needing to manage Dante devices on the AV VLAN.

Real-World VLAN Setup Example

Network Topology:

• Main office VLAN: 192.168.1.0/24
• AV VLAN: 192.168.100.0/24

Switch Configuration:

• Ports 1-20: untagged VLAN 1 (office)
• Ports 21-24: tagged VLAN 100 (uplinks/backbone)
• Port 25: untagged VLAN 100, connected to Dante switch
• Port 26: tagged VLAN 1 + 100, connected to Dante Controller laptop

This allows the Dante Controller (on VLAN 1) to discover and manage Dante devices (on VLAN 100) while isolating audio flows to the AV VLAN.

Dante and AES67 on VLANs

dante and aes67 networks can operate entirely on their own VLAN. However, some integrators run a separate AV network switch altogether (not VLAN'd) for critical applications, valuing simplicity and isolation over IT integration.

For less critical systems, a shared managed switch with proper VLAN and QoS configuration is cost-effective and IT-friendly.

Common VLAN Mistakes

Forgetting the Gateway — If AV VLAN and office VLAN can't route to each other, management tools and control systems fail.

Port Misconfiguration — Untagged AV ports appearing on wrong VLAN, or missing tag on trunk links, breaks network connectivity.

No QoS on VLAN — VLAN isolation alone doesn't prevent congestion. Apply qos-for-audio rules to AV VLAN.

Mixing Device Types — Putting office printers or phones on AV VLAN complicates troubleshooting and defeats isolation benefits.

Practical Setup Checklist

1. Define IP subnets for each VLAN
2. Identify all AV devices that belong on the AV VLAN
3. Plan switch ports — which are access ports, which are trunk
4. Configure VLAN tags on the switch (consult manufacturer docs)
5. Test connectivity between AV devices and management stations
6. Apply QoS policies to prioritize AV VLAN traffic
7. Document the setup — include VLAN IDs, subnet masks, port assignments
8. Brief the IT team on AV VLAN purpose and maintenance needs

Coordination with IT

Many organizations have network teams. Involve them early. VLANs are standard IT practice; network admins usually welcome proper AV VLAN planning over "can we just run another cable?"

Provide clear documentation of VLAN requirements, explain the business need (real-time delivery, isolation), and offer to help test and troubleshoot.

Common Pitfalls

• Forgetting to Trunk VLAN Tags Between Switches — When connecting multiple switches, trunk ports must be configured to carry tagged VLAN traffic. Missing trunk tags causes VLAN traffic to fail on inter-switch links.
• IGMP Snooping Disabled by Default — Many managed switches have IGMP snooping disabled out of the box. Without it enabled, multicast AV streams flood all VLAN ports, degrading performance.
• Mixing Dante and Video on Same VLAN Without QoS — Combining low-latency audio (Dante) and streaming video (which can be bursty) on a single VLAN without careful bandwidth allocation causes audio dropouts.
• Wrong Gateway or Routing Configuration — If your AV VLAN and office VLAN can't route to each other, control systems, Dante Controller, and remote management tools become inaccessible.