Abstract
Ethernet is a widely used low-cost networking technology. It however lacks the determinism and resource management features needed to meet real-time requirements of multimedia applications, for instance. This paper presents the B E A T communication service that adds basic real-time mechanisms on top of Ethernet to the Linux operating system while supporting the use of conventional applications and protocols such as TCP and UDP.
To avoid the indeterminism of the CSMA/CD network access control a token mechanism has been employed. Priorities can be attached to packets and are taken into account in allocating bandwidth locally, for the messages on the node, as well as gobally, among the nodes on the network. Moreover, shares of network bandwidth can be reserved by tasks, controlled by a utilization-based admission test. In addition, a global notion of time is neede for time constraints to be meaningful in a distributed real-time system. B E A T therefore integrates a clock synchronization algorithm with the communication mechanisms. By directly accessing low-level packet transmission an accuracy in the order of 10 μs is achieved. The overhead introduced by the B E A T communication service is about 10% for processing time as well as for network bandwidth.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bill O. Gallmeister. POSIX.4’ Programming for the Real World. O’Reilly & Associates, January 1995.
International Organization for Standardization. ISO 8802-3; Information processing systems — Local area networks — Part 3: Carrier sense multiple access with collision detection (CSMA/CD) access method and physical layer specifications, 1989.
International Organization for Standardization. ISO/IEC 8802-5; Information technology - Telecommunications and information exchange between systems - Local and Metropolitan area networks - Specific requirements - Part 5: Token ring access method and physical layer specifications, 1995.
R. Koster. Design of a real-time communication service for local-area networks. Diplom thesis, Department of Computer Science, University of Kaiserslautern, May 1998.
R. Koster and T. Kramp. Smart proxies for end-to-end QoS control. In Proceedings of Middleware 2000 (International Conference on Distributed Systems Platforms and Open Distributed Processing). IFIP/ACM, April 2000.
James F. Kurose, Mischa Schwarz, and Yechiam Yemini. Multiple-access protocols and time-constraint communication. Computing Surveys, 16(1), March 1984.
K. W. Tindell, A. Burns, and A. J. Wellings. Guaranteeing hard real-time end-to-end communications deadlines. Technical Report RTRG/91/107, University of York, UK, December 1991.
C. Venkatramani and T. Chiueh. Design, implementation, and evaluation of a software-based real-time ethernet protocol. In Proceedings of ACM SIGCOMM ’95, 1995.
Wei Zhao and Krithi Ramamritham. Virtual time CSMA protocols for hard realtime communication. IEEE Transactions on Software Engineering, 13(8):938-952, August 1987.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Koster, R., Kramp, T. (2001). Real-Time Support on Top of Ethernet. In: Killat, U., Lamersdorf, W. (eds) Kommunikation in Verteilten Systemen (KiVS). Informatik aktuell. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-56675-2_36
Download citation
DOI: https://doi.org/10.1007/978-3-642-56675-2_36
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-41645-6
Online ISBN: 978-3-642-56675-2
eBook Packages: Springer Book Archive