sACN — Streaming ACN (E1.31)
Definition
sACN (Streaming ACN), standardised as ANSI E1.31, is a protocol that carries DMX512 data over IP networks, usually in UDP multicast. It addresses up to 63,999 universes. Each universe is sent to its own multicast group, so a switch with IGMP snooping forwards it only to the ports whose devices have subscribed to it, and the protocol suits large installations for that reason. A priority field (0 to 200) lets receivers choose between several sources of the same universe, which allows redundant sACN sources without conflict. Efficient multicast delivery depends on managed switches with IGMP snooping enabled.
In the field
On an unmanaged switch, sACN multicast traffic is flooded to every port and can overload devices that never subscribed to it. Large rigs therefore use managed switches with IGMP snooping enabled for sACN.
Related lessons
Sources
- ANSI E1.31-2018 (ESTA), Lightweight streaming protocol for transport of DMX512 using ACN : univers 1 à 63 999, priorité 0 à 200 (100 par défaut), multicast UDP · tsp.esta.org
- IETF RFC 4541 : fonctionnement de l'IGMP snooping sur les switches · rfc-editor.org
- Wikipédia (pointeur secondaire), Architecture for Control Networks : sACN (E1.31), multicast par univers · en.wikipedia.org