Ethernet Switching is the technology of choice for the vast majority of distributed Automation Systems.

The technology dates back to 1973 when Bob Metcalf developed the concept as a shared, high-speed, medium for transmission. The original shared '10Base5 / 10Base2 / 10BaseT (hub)' technology implementation became a victim of its own success and evolved into the switched platform now common place. Transmission speeds have increased 1000 fold over the years with backbones now able to operate at up to 10Gbps.

More typical speeds deployed in Automation projects are 1Gbps for Server connection and the distributed backbone. Access devices connect at 100Mbps.

The emergence of Full Duplex transmission in the late 1990's and the wire speed forwarding that became common place in 2000-2005 issues of determinism have been largely eradicated. At least they can be by good design.

The switching opportunity of today relates to optimisation and the challenge security.


Multiple network services can now be consolidated across a common resilient and high speed backbone without compromise.

This consolidation makes for simplified management and administration, it allows networks to be designed with no single point of failure and also dual redundant topologies where application services are protested from both communication path failures and switch node failures.

IT4A's critical network design methodology uses threat assessment and risk treatment planning to underpin both product and feature selection. This approach allows the investment in network infrastructure to be linked directly to business continuity planning.


Network security is often described as an onion skin as there are many layers. The first layer is physical and considers media (copper/fibre) selection, routing and containment.

At the second 'Ethernet' layer security is achieved though the deployment of features such as VLANs for segmentation by application and 802.1x, port locking and strong passwords to control access through effective authentication.