Abstract - Technical Program - ES 99
RETHER: A Software-Only Real-Time Ethernet for PLC Networks
Tzi-cker Chiueh, State University of New York at Stony Brook
Abstract
The networking technologies used in industrial automation
are required to support real-time performance guarantees
to ensure that sensor/command data reach target nodes
within a delay bound. With the continuing popularity and thus
the accompanied price drop of the Ethernet technology, replacing
the typically closed and proprietary automation networks with
Ethernet is emerging as a very attractive solution, because
of the cost-effectiveness and its compatibility with the trend
of moving industrial control systems to PC-based hardware.
Due to its contention-based media access control protocol,
Ethernet theoretically can not bound the network access delay without
additional traffic control mechanisms.
In this work, we present the design, implementation, and programming
interface of a software-based traffic control protocol called RETHER ,
which turns off-the-shelf Ethernets into real-time networks
without any hardware modifications. RETHER works both in
a single-segment as well as a multi-segment
environment. This paper reports the performance measurements
and implementation experiences with the RETHER prototype, which
has been fully operational for over 12 months.
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