Computer Communications
SIGMETRICS '94 Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems
Statistical Real-Time Channels on Multiaccess Bus Networks
IEEE Transactions on Parallel and Distributed Systems
A Steady-State Analysis of CSMA-CD
Performance '84 Proceedings of the Tenth International Symposium on Computer Performance Modelling, Measurement and Evaluation
Soft Real-Time Communication over Ethernet with Adaptive Traffic Smoothing
IEEE Transactions on Parallel and Distributed Systems
On the design and implementation of a shared memory dispatcher for partially clairvoyant schedulers
International Journal of Parallel Programming
The hard real-time problem on ethernet
CSN '07 Proceedings of the Sixth IASTED International Conference on Communication Systems and Networks
Enforcing the timing behavior of real-time stations in legacy bus-based industrial Ethernet networks
Computer Standards & Interfaces
Research and application of flexray high-speed bus on transformer substation automation system
WISM'10 Proceedings of the 2010 international conference on Web information systems and mining
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In order to realize real-time communication over Ethernet or fast Ethernet, one must be able to bound the medium access time within an acceptable limit. The multiple access nature of Ethernet makes it impossible to guarantee a deterministic medium access time (hence, packet-delivery deadlines) to individual stations. However, one can bound the medium access time statistically by limiting the packet-arrival rate at the medium access control (MAC) layer. While considering automated manufacturing systems as the main target application, this paper addresses the connection admission control (CAC) problem for statistically bounding the medium access time of Ethernet. Specifically, a packet is guaranteed to have a medium access time smaller than a predefined bound with a certain probability if the instantaneous packet-arrival rate is kept below a certain threshold. Through a mathematical analysis, we first derived such a threshold. In order to keep the packet-arrival rate under the given threshold, we developed and installed a middleware which 1) resides between the transport layer and the Ethernet datalink layer and 2) smooths packet streams between them. The implementation of this middleware requires only a minimal change in the OS kernel without any modification to the current standard of Ethernet MAC protocol or TCP or UDP/IP stack. In order to solve the CAC problem, we derived the probability of transmitting a packet successfully upon each trial by modeling the MAC protocol, 1-persistent CSMA/CD, and the collision resolution protocol驴Binary Exponential Backoff驴of Ethernet. Our in-depth simulation results have shown this analytic model to provide a reasonably accurate estimate of packet-loss (or deadline-miss) ratio over Fast Ethernet. Finally, we implemented the middleware on the Linux OS, experimentally demonstrating the effectiveness of our approach in providing real-time communication over Ethernet.