Full of fibre

Wim D’Hooghe of OTN Systems explains the importance of secure telecommunication networks in transportation.

The most important telecom subsystem for metro organisations, intelligent motorways, bridges or tunnels is the fibre optic backbone. It carries all the information needed to run the daily operations. Needless to say that the network should be extremely reliable and provide maximum resilience to cope with the inevitable faults that will occur, e.g. cable breaks.

Another important requirement of the network is that it should be easy to manage. Actually, it should be child's play. Unlike enterprise equipment, network (software) upgrades should be avoided. In most cases there's simply not enough time to switch back to the 'old' configuration, so, why take the risk? Also, make sure the backbone has a guaranteed life span of at least 10 years, preferably 15. 

Connect all applications
The last thing you want to do is install multiple networks for the different applications. It would not only cost an arm and a leg but it would also become very hard to manage and lead to a high OPEX (Operational Expenditures). Keep things simple and choose a network that can combine all the applications without jeopardizing the performance of any of them.

A metro environment is probably one of the most complex ones because of the wide variety of applications encountered, including safety applications, security, train control, passenger information, station management, etc. Moreover, each of these applications have their own specific requirements towards the transmission network. The CCTV application can only tolerate a maximum delay of 150 milliseconds (from camera to control room display - for pan-tilt-zoom purposes), the radio network might require synchronous links, the SCADA system might need a process control type of connection. 

Not to mention the legacy equipment that still might be out there with its traditional (analogue) interfaces. To make things even more complicated, you don't want any of these applications to interfere with one another. Imagine a surveillance system bringing your SCADA down due to unforeseen high traffic - completely unacceptable. Hence, choose a system that can guarantee 100 percent separation between every single application.

Superiority of fibre optics

Installing fibre has become nearly as easy as pulling a copper cable. The connectors available on the market today make a fibre installation really plug and play. The benefits of fibre are numerous. The bandwidth provided is virtually unlimited as well as the distances that can be spanned. We are no longer talking about Gbps (Gigabits per second) but Tbps (Terabits per second), far beyond the bandwidth that is currently needed to run the daily operations. But who knows what the future will bring?

Also, fibre cable is immune to electromagnetic interference. EMC is often a nightmare for the equipment manufacturers as well as for the end users. So, keep copper cable to a minimum, for the short distances only. Today, fibre cable has become a no-brainer in the industry.

Transport network

It should operate round-the-clock and be impossible to break into. The latter is easier said than done. Open standards have brought us interoperability and the Internet, but also hackers and firewalls. The train operator's worst nightmare is that someone breaks into the network and accesses the train signalling or safety applications. Not only could it stop the system from operating but it could also put lives in danger. My recommendation: take all possible precautions and select a system that is designed for the worst case scenario. 

Wim D'Hooghe is co-founder and CEO of OTN Systems.  Prior to that he was in charge of all indirect business and the industrial market at Nokia Siemens Networks and, at Siemens, was in charge of the OTN Business Unit.