wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

67-2 Industrial Communication Systems
card or via user name and password. Unfortunately, there is no universal concept of identity established.
Every technology—and even providers—have their own flavor of the two mentioned methods.
An industrial communication system, hooked up to such a provider’s infrastructure has to deal
with a heterogeneous mix of technologies like IP-Proxy-Routers, dial-up protocols, digital certificates,
authentication protocols, and passwords. Unfortunately, there is no single-sign-on (SSO) standard for
ICS infrastructure that could be compared to SSO in the IT world.
Sun Java• System Access Manager [SUN05] is an M2M-capable SSO solution that provides federated identity
(authentication and authorization) support via Liberty Alliance Phase 2 and Security Assertion Markup
Language (SAML), session management, delegated authority, and on-the-fly audits of authentication attempts.
Another approach, also out of the mobile communication world, comes from the European
Telecommunications Standards Institute (ETSI). ETSI discusses future M2M architectures in its technical
committee ETSI TC M2M#01 and calls SSO “Identity Federations Service,” implemented by an
M2M service gateway [ETSI09].
Traditional industrial networks still do not have anything like this, but it can be expected that IT, telecommunication,
and industrial communication will further converge, so that IT solutions will be adopted for ICS.
67.3 Vertical Integration
ICS were and are traditionally used for automation, data acquisition, process monitoring, and other
tasks that are “near the process.” Recent trends in production show, however, an increasing link between
the shop floor and administrative parts of an enterprise. Applications like supply chain management
and digital ecosystems are first versions of totally integrated business processes.
This trend is reinforced by ecological constraints and the increased need for energy efficiency. In
order to calculate the carbon footprint of a produced product, it is necessary to link data from a large
variety of sources. This includes automation data, schedules, supplier information, and logistics data.
Even if the various IT systems of these sources (enterprise resource planning software, manufacturing
automation, logistics and fleet management, energy consumption equipment, etc.) are somehow interlinked,
they usually lack a common management and a common language to exchange information.
Transmitting data “from I/O to CEO” is therefore not only a problem for the transport media but
more a question of semantics and lossy translations between IT systems. The increased use of IT technologies
like web services, XML, and service-oriented architecture (SOA) eases this goal. Organizations
like OASIS [OASIS] are engaged in applying web services and XML-based formats to all kinds of businesses
and processes. One example is oBIX [Ehrl03] for exchanging building data.
Also, the design and specification phase of industrial installations is more and more influenced by
traditional IT methods. UML-PA [UMLPA] and OPC XML DA [OPCDA] are examples of the successful
usage of IT methods for industrial systems.
True interworking and interoperability consists of a number of steps. The prerequisite is protocol conformance,
i.e., using the right plugs, frames, addresses, coding, timing, etc. Above protocol conformance
comes the application with its data types and functional profiles. One important, although often forgotten
factor is interoperable network and application management and configuration. While protocol conformance
usually leads to interoperable network management, the applications still might use some proprietary
way of storing their configuration parameters. SOA and the use of XML-based data formats eases the
“lower” parts (i.e., data representation and encoding) of application management; the semantics and usage
of the individual parameters, however, must be defined in standardized high-level profiles.
67.4 Hybrid Local Networks and Quality of Service
Most ICS were designed with a particular application domain in mind. There are networks for network-based
control, for drives, for data acquisition, multimedia streaming, or fire alarm systems.
The application domain resulted in specific features like low latency, guaranteed time slots, good
© 2011 by Taylor and Francis Group, LLC