Configuring VLANs on Lawo Switches for Isolated Control and Audio Traffic
A well-designed VLAN structure keeps Lawo control traffic, AoIP streams and switch management separate without making the studio harder to operate. For radio facilities using Ruby consoles, Power Core nodes, VisTool and related Broadcast 3.0 components, this separation improves fault finding and limits the impact of a mispatched cable or an incorrectly configured device.
The practical aim is straightforward: audio must remain predictable, control traffic must remain reachable, and management access must be restricted. The exact commands depend on the switch manufacturer and firmware, but the network principles remain consistent across a Sydney network studio, a Melbourne production hub or a regional station supporting several sites.
| Traffic role | Typical VLAN purpose | Main considerations |
|---|---|---|
| Audio transport | RAVENNA or AES67 media flows | Multicast, bandwidth, QoS and low jitter |
| Control | Console, DSP and automation control | Reliable reachability without unnecessary exposure |
| Timing | PTP clock distribution | Consistent priority and minimal path changes |
| Management | Switch, node and monitoring access | Restricted access, logging and fixed addresses |
Start With Traffic Roles
Begin by listing every endpoint and the traffic it generates. A Ruby surface may need control access to a Power Core audio node, while the audio streams themselves move through the AoIP network. VisTool workstations, automation computers and monitoring tools may require selected access to both control and media services, but they should not automatically sit in the same broadcast domain as switch administration.
A common design uses separate VLANs for audio, control, timing and management. Some facilities combine control and timing when the equipment vendor’s design permits it, but that decision should be tested rather than assumed. Keep a current port schedule showing the switch name, port number, connected device, VLAN mode and expected traffic type.
For Australian broadcasters, this planning matters when a central facility in Brisbane supports a smaller Gold Coast studio, or when a Perth operation has engineers travelling between sites. A clean local design reduces the amount of troubleshooting that depends on a remote specialist or an after-hours call.
Build A Clear Address Plan
Assign an IP subnet to each VLAN and reserve addresses for core devices. Use fixed addresses or DHCP reservations for Power Core units, switches, timing sources and key workstations. Document the gateway, subnet mask, DNS requirements and permitted inter-VLAN paths before making changes.
Access ports normally carry one untagged VLAN for an endpoint. Trunk ports carry multiple tagged VLANs between switches, routers and approved infrastructure. Set an explicit native or untagged VLAN where required, and avoid leaving unused VLANs available on every trunk. A mismatch between tagged and untagged expectations can make a Lawo device appear offline even though its link light is active.
Routing should be deliberately limited. A management workstation may need access to switch web interfaces and device diagnostics, while an audio endpoint generally does not need unrestricted access to corporate services. Use firewall rules or access control lists to permit only the control flows and management protocols that have been tested.
Configure Switch Ports Carefully
Create the VLANs first, then apply them to ports according to the design. Enable edge or rapid spanning-tree settings on ports connected to endpoints, while keeping inter-switch links in the appropriate network-facing mode. Disable unused ports and place them in an inactive or quarantine VLAN rather than leaving them open.
Multicast handling is central to RAVENNA and AES67 deployments. Enable IGMP snooping on the audio VLAN, and provide an IGMP querier when the VLAN does not have a suitable multicast router. Without proper membership control, every audio stream can be flooded to every port, consuming bandwidth and increasing processing load.
Quality of service should prioritise time-sensitive media and PTP traffic above ordinary management or file-transfer traffic. Confirm the switch’s queue mappings, trust boundary and DSCP treatment instead of relying on default settings. A busy NBN-connected office service or a large file copy should never be allowed to compete equally with live studio audio inside the production network.
Protect Timing And Control
PTP deserves its own review because a VLAN can be logically correct while timing still performs poorly. Keep the preferred grandmaster visible to the relevant devices, and avoid unnecessary Layer 3 hops between the clock source and audio endpoints. Check whether the selected switch supports the PTP mode and profile required by the Lawo and AoIP equipment in use.
Control traffic is usually lighter than audio traffic, but it is operationally important. Console surface commands, routing changes, monitoring states and software control sessions should remain available during normal network activity. Permit required control traffic between the control VLAN and audio devices, while blocking broad access from general office computers.
When integrating Ruby mixing consoles into an existing facility, review the console, Power Core and workstation paths together. A VLAN change that protects the switch may still interrupt discovery, device control or configuration software if the required multicast or routed services have not been allowed.
Test The Whole Signal Path
Test from the operator’s position, not just from the switch cabinet. Confirm that the console can control the intended audio engine, sources appear correctly, outputs remain stable and monitoring behaves as expected. Check both directions of the path, including return feeds, talkback and contribution circuits.
Use switch counters and monitoring tools to inspect multicast group membership, errors, dropped packets, queue congestion and link negotiation. Verify PTP lock and offset on representative endpoints. A short test tone is useful, but sustained audio and realistic source changes reveal problems that an idle network can hide.
Schedule changes around local operating patterns. A station serving a country area may have fewer technical staff on site, while a metropolitan newsroom in Sydney or Melbourne may have intense breakfast and drive programming windows. Avoid a Friday afternoon cutover before an important weekend broadcast; record a rollback configuration and test it during a controlled maintenance period.
Roll Out With Evidence
Make one controlled change at a time and save the switch configuration before editing VLANs, trunks or multicast settings. Record firmware versions, port assignments, IP details and the date of each test. Keep the final diagram close to the rack, with enough detail for an engineer arriving on an urgent call.
For multi-site Australian operations, distinguish local VLANs from routed links between facilities. Do not stretch an audio VLAN across a carrier service unless latency, multicast behaviour, timing and failure modes have been specifically engineered. Regional links, temporary outside broadcasts and FIFO-style deployment schedules often require a simpler local fallback rather than dependence on a distant control room.
The next concrete step is to export the current switch configuration, create a port-and-VLAN register, and test the proposed audio, control, timing and management separation on one non-critical Lawo rack during the next maintenance window.
