Switch Requirements for Dante Networks
The four settings that matter
1. QoS — DiffServ, not 802.1p
Dante uses DSCP marking. Clock packets must land in the highest priority queue, audio one below, everything else in best effort.
| Traffic | DSCP | Queue |
|---|---|---|
| PTP clock (event) | 56 (CS7) | Highest |
| Audio | 46 (EF) | High |
| Reserved | 8 (CS1) | Medium |
| Other | 0 | Best effort |
If clock and audio share a queue, the audio bursts delay the clock and the domain loses sync under load.
2. IGMP snooping — with a querier
Multicast flows without IGMP snooping are flooded to every port. On a 48-port switch, that turns eight multicast flows into a broadcast storm. Enable snooping, and make sure exactly one querier exists on the VLAN.
3. Energy Efficient Ethernet — off
Disable EEE (802.3az) on every port carrying audio.
Energy Efficient Ethernet is the single most common cause of intermittent, unreproducible dropouts on otherwise healthy audio networks. Turn it off before you troubleshoot anything else.
4. Hop count and latency
Default device latency of 1 ms covers three hops of gigabit switching. Count hops on the drawing, not on site.
| Hops | Minimum latency setting |
|---|---|
| 1–3 | 1 ms |
| 4–10 | 2 ms |
| Beyond, or 100 Mbps links | 5 ms |
Commissioning checklist
- QoS profile applied and verified on every audio port
- IGMP snooping on, one querier per VLAN
- EEE disabled globally
- Flow control disabled
- Audio VLAN separated from general IT traffic
- Clock master election checked after full power-up
Frequently asked
Can I use an unmanaged switch for Dante?
On a small system with only unicast flows and no other traffic, yes. Once you add multicast flows, a second switch, or shared IT traffic, you need a managed switch with QoS and IGMP snooping.
Why does Energy Efficient Ethernet break Dante?
EEE puts ports into low-power states between packets. The resulting jitter disturbs PTP clock recovery, which shows up as intermittent dropouts that are very hard to trace.
How many switch hops can Dante tolerate?
Three hops at the default 1 ms latency setting. Beyond that, raise the device latency setting rather than hoping it works.