YOKOGAWA Vnet/IP, Technical Information

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1. Overview of Vnet/IP
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TI 30A10A05-01E
1.1 Vnet/IP Features
Vnet/IP is a process automation control network that is based on gigabit Ethernet. It has
the features that are important for a stable plant operation, namely high reliability, and
real-time response. It also provides security against threats from an external network,
such as cyber attacks.
Vnet/IP connects the devices that make up the CENTUM and ProSafe-RS systems. It
allows the exchange of control data among these devices. Vnet/IP can also connect to
other systems that use V net or VL net as their control network by using a V net router.
You can use network devices such as Layer 2 Switch (L2SW) or Layer 3 Switch (L3SW),
and transmission media such as UTP cables or optical fiber cables to set up Vnet/IP.
Vnet/IP is a control network that complies with the international standard (IEC 61784-2
Ed.2.0) and conforms to IEEE 802.3 and UDP/IP.
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High reliability
Vnet/IP is a control network with dual redundant buses and consists of independent subnets, bus
1 and bus 2. The control communication is usually performed by using bus 1. However, when
a problem occurs in bus 1, the path switches immediately and automatically so that the control
communication is performed by using bus 2.
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Real-time response
Vnet/IP implements a dedicated protocol for performing high-quality communication on UDP/IP,
which is a protocol that is suitable for real-time communication.
The transmission scheduling function prevents transmission delays and packet loss by stopping
packets from being accumulated. Real-time response is achieved by prioritizing among the
different communication types.
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Security
Vnet/IP takes security into account. It performs authentication by using a shared secret key that
is updated periodically to prevent cyber attacks such as data eavesdropping, falsification, and
spoofing.
SEE
ALSO
For more information about Vnet/IP security features, refer to the following.
“Security Standard of System Product” (TI 30A10A20-01E)
In this document, we recommend that you perform non-control communication, which is
information communication, on an information network other than Vnet/IP. If the information
network is not used but Vnet/IP is used for both control communication and information
communication, refer to the conditions described in Chapter 1.6 of this document
Aug.19,2011-01