Popular wisdom says Ethernet is non-deterministic. This characteristic leads to consider it unsuitable for Real-Time services, since its fundamental access algorithm, called CSMA/CD, could not provide sufficiently consistent latency for deterministic applications. Simplifying, Ethernet is not able to ensure an access delay within a range known "a priori". At the moment, only three solutions for that problem in the industrial field are able to capture the attention, such as EtherCAT, Ethernet Powerlink and Profinet. This article shows analytically the Ethernet non-deterministic aspect and proposes a new solution that allows using Ethernet in industrial real time environments. Moreover it compares previous solutions with the proposed new one, pointing out pros and cons.
The Hard Real-Time Problem on Ethernet / Santacaterina, A; DI BIAGIO, C; Pennella, G; Nanni, Umberto. - STAMPA. - (2007), pp. 69-75. (Intervento presentato al convegno 6th IASTED International Conference on Communication Systems and Networks, CSN 2007 tenutosi a Palma de Mallorca; Spain nel 29/08/2007 - 31/08/2007).
The Hard Real-Time Problem on Ethernet
NANNI, Umberto
2007
Abstract
Popular wisdom says Ethernet is non-deterministic. This characteristic leads to consider it unsuitable for Real-Time services, since its fundamental access algorithm, called CSMA/CD, could not provide sufficiently consistent latency for deterministic applications. Simplifying, Ethernet is not able to ensure an access delay within a range known "a priori". At the moment, only three solutions for that problem in the industrial field are able to capture the attention, such as EtherCAT, Ethernet Powerlink and Profinet. This article shows analytically the Ethernet non-deterministic aspect and proposes a new solution that allows using Ethernet in industrial real time environments. Moreover it compares previous solutions with the proposed new one, pointing out pros and cons.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
