Network Hardware
Definition
A switch connects devices within a single network, at layer 2 of the OSI model, while a router forwards traffic between different networks at layer 3. In an AV system the switch has the largest effect on reliability, and the main distinction is between managed and unmanaged models. An unmanaged switch forwards traffic with no configuration at all. A managed switch can be configured with VLANs (IEEE 802.1Q) to separate traffic, with quality of service (QoS) to give priority to clock, audio and control packets, and with IGMP snooping.
The guide
IGMP snooping matters because Dante, AES67 and sACN can all use multicast, in which one source sends a stream to many receivers. A switch without IGMP snooping forwards multicast like broadcast, to every port, so devices that never asked for a stream still receive it. A snooping switch reads the IGMP membership reports sent by receivers and forwards each multicast group only to the ports that joined it, as described in RFC 4541. Snooping relies on the periodic queries of an IGMP querier, a role that many managed switches can take. Dropouts on an audio network or an LED processor connected to an unmanaged switch often stop once the system is moved to a managed switch configured for multicast.
Audinate recommends gigabit switches for Dante. Links at 100 Mbit/s are supported when QoS is configured, and Energy Efficient Ethernet (EEE) is disabled on the ports that carry Dante. Professional practice therefore relies on managed gigabit switches whose configuration is known and documented.
The rule
A professional AV network is built on managed switches configured for multicast and quality of service.
Glossary terms
Sources
- IETF RFC 4541 (2006) : fonctionnement des switches à IGMP snooping ; un switch peut par défaut transmettre le multicast non enregistré sur tous les ports · datatracker.ietf.org
- IEEE 802.1Q-2022 (Bridges and Bridged Networks) : norme des VLAN et des trames étiquetées · standards.ieee.org
- Audinate FAQ, Networks and Switches : gigabit fortement recommandé, 100 Mbit/s admis seulement avec QoS · support.getdante.com
- Audinate FAQ, Can I use EEE (Energy Efficient Ethernet or Green Ethernet) in my Dante network? EEE à désactiver sur les ports Dante · getdante.com
- Audinate/Yamaha, Dante Network Design Guide, QoS : priorités DSCP sur les réseaux Dante · usa.yamaha.com
- Audinate/Yamaha, Dante Network Design Guide, Multicast : IGMP snooping et querier sur les réseaux Dante · usa.yamaha.com