Mission critical multi service network for public transit systems

Although it represents only a small fraction of the cost, compared to civil works or rolling stock, the communication network plays an ever increasing role in the operation of mass transit systems. Because of its growing importance, the requirements for a communications backbone become more elaborate. This article gives an overview of the aspects that make the Open Transport Network (OTN) ideally suited to support the Transport Authority’s operations.

Support of all applications

The basic task of a communications backbone is to support all applications which are needed to operate the transit system. Applications range from operational needs such as Telephony, Intercom, Supervisory Control and Data Acquisition (SCADA), LAN networks, Passenger Information Systems and Public Address, to passenger security related services such as emergency call boxes or CCTV (Closed Circuit Television) surveillance. On top of all this, the network must also be capable to support new applications as they will appear in the future.

The OTN communications backbone is able to support these new and legacy applications directly, without the need for external adapters or signal convertors.

Bandwidth guarantee

To support all public transport applications on a single network, the OTN network guarantees a dedicated amount of bandwidth to each application while maintaining a strict separation between the different applications. In this way mutual interference between applications is avoided.

This provisioning of bandwidth also allows the creation of multiple, fully independent Ethernet networks (LANs) over a single OTN network. In this way an Ethernet or IP based application can be 100% separated from an administrative LAN or a SCADA LAN.

Bandwidth in abundance

In case a high number of video cameras and other bandwidth consuming applications will be connected to the network, a 10Gbps OTN network can be selected as telecommunications backbone. This high capacity OTN backbone provides plenty of spare capacity for future expansions with new stations or additional applications.

Reliability

As the communications backbone carries back all the vital information to the control center(s), it is mandatory that OTN provides the necessary redundancy features to survive component failures (e.g. loss of power supply) or cable breaks. The OTN network is designed to guarantee high reliability and redundancy even in the harsh environment of an outdoor cabinet or tunnel equipment shelter. The use of an optical fiber infrastructure provides excellent immunity to electromagnetic noise, caused by the trains or other trackside equipment.

Simplicity

The operation of a large transit system is a complex business by itself, so the configuration and management of the OTN communications network is designed to be a simple as possible.

OTN provides an integrated network management system, which manages everything from the optical fiber connection down to the application interface port. This makes the network management easy and facilitates maintenance, which further decreases operational costs.

Security

Cyber Security is an increasing concern in Public Transport infrastrucure. By separating application data from the network management communication channel, the OTN network provides a strong resistance against hackers.

Future Proof

Unlike office network equipment, which is usually replaced after 3 years, networks for transit systems have a life span of 10 to 15 years or more, during which period OTN guarantees product support. Downtime for upgrades or updates has to be avoided or must be limited to a strict minimum, usually during the night. Therefore the design of the OTN network is such that it can grow with the increasing need for new applications, with limited or no downtime.

Revolutionary Video Monitoring and Recording concept

An important issue in the Transport Authority's operation is passenger safety. Therefore a state-of-the-art video surveillance application is integrated on the OTN network, which can easily scale from a few to 1000+ cameras. The camera images are encoded by high quality H.264 video encoders, which are integrated in the OTN network nodes. The encoded digital video information is then transported over the OTN network to the location(s) where the images are recorded on redundant storage servers.

The live and recorded images can be viewed by means of an NVR (Network Video Recorder), which allows live monitoring and which can be used to search for specific events in the recorded footage. In case of an incident, the NVR will be used to provide proof to the proper authorities.

The recorded video images can be stored on standard IT hardware. This means that standard RAID (Redundant Array of Inexpensive Disks) technology can be used to avoid the loss of recorded images in case a storage hard disk fails. As the number of cameras increases over time, the NVR's capacity can easily be upgraded by installing additional storage disks in the storage array.

Rely on OTN to get your operational information across in a reliable and easy way

The successful implementation of OTN's innovative networking solution at Transport Authorities around the world is based on more than just technology. It is also a matter of people and know-how.

Since 1990 OTN Systems has developed and deployed dedicated fiber optic communications networks for metros, light rail systems, people movers and railways in 34 countries all over the world. This long term relationship with more than 100 leading Transport Authorities has led to the continuous innovation of the Open Transport Network, so that it meets today's and future requirements.

If you would like to learn more about OTN Systems' products such as the new OTN-X3M 10Gbps platform, or if you would like to visit a company that uses OTN in your area, please contact us at or visit www.otnsystems.com.