SCADA systems while the terminals and RTUs are presently connected
through a local area network. The conditions in a process plant are harsh
and the site is remote. Resources for data communication are difficult to
obtain under the environment and a wireless channel communication
through a cellular phone is practical and efficient. The mobile service can
be incorporated into the DNP protocol such that a wireless WAP phone can
reach and operate the resources available in a SCADA system [ 7 ].
Robert H. in 2003 discussed improvements in cost/benefit and
flexibility of both SCADA systems and corporate networks that can be
achieved by combining the goals of the two onto a single, multipurpose
network based on IP (Internet Protocol) protocols. This allows the cost-
justifications for these functions to be taken collectively, making the
combined networking project more economically viable. Among these
cost/benefit and flexibility improvements are the following [ 8 ]:
1 - The convergence of many types of services onto IP-based networks
makes it possible to implement a single WAN that can meet most of
a utility’s network needs between remote offices, including SCADA.
2 - A combined SCADA/corporate network can serve as the long-haul
portion of the SCADA network, allowing the SCADA-specific focus
to be on last-mile connectivity to RTUs.
Hamoud G., et al., in 2003 presented a practical method for
quantifying the risk associated with the failure of the SCADA systems
utilized in power systems. The method first identifies the various
components of risk and then evaluates each by considering overlap of the
two events, failure of control by SCADA and failure of automatic operation
of the power system network. The proposed method is applied to the Hydro