By Mae Kowalke, TMCnet Contributor
Rail communications have not been immune from the information technology revolution, but any new rail solutions need to be rock-solid since safety is on the line. Rail communications failure is just not an option.
Moving from separate network services to a converged IP/MPLS multi-service network is helping railway operations make a step-change in flexibility and efficiency while reducing total cost of ownership.
IP convergence--and IP/MPLS in particular—bring safety-related train control communications under a single unified architecture while delivering new railway communications flexibility.
One railway operations pioneer, Portugal’s REFER Telecom (the telecommunications subsidiary of Portuguese railway infrastructure manager, REFER E.P.E), has been using a fixed IP communications network since 2004. Since 2008 it has been running on IP/MPLS technology provided by Alcatel-Lucent.
“The evolution of technology and the obsolescence of some of our existing technologies was a driver,” explained João Figueiras, head of data networks for REFER Telecom, in a recent Alcatel-Lucent TrackTalk article. “We understood that the TDM technology was becoming inadequate for new deployments, and that copper cables had to be deactivated. The deployed fiber network and the increased copper thefts have also accelerated the migration process to IP technology.”
IP convergence has meant has helped REFER reach its goal of failure recovery in less than 50ms, shortened time delay, and clear traffic separation.
IP/MPLS has enabled it to have path restoration and network reconvergence through the MPLS Fast Reroute (FRR) feature, according to the blog post, which secures the network against failure by provisioning standby end-to-end MPLS paths which protect the active path. Further, different traffic types are segregated using MPLS pseudo wire emulation edge-to-edge (PWE3) and virtual private networks (VPNs), which deliver user groups or applications with an environment that is unaffected by other traffic.
Milan’s Azienda Trasporti Milanese (ATM) also has seen the benefits of moving its rail communications to a converged IP network.
“The necessity to upgrade to an IP network is due to the increasing need to host more services and its ability to converge these onto a single piece of infrastructure to provide a truly multi-service network,” explained Stefano Pasetti, director of mobile and telecommunications for ATM, in a separate TrackTalk posting.
The introduction of VoIP systems and the necessity to guarantee different quality of service specifications led ATM to IP/MPLS.
“This communication network is designed to be resilient and to guarantee high reliability for critical services like the new SCADA (Supervisory Control and Data Acquisition) system of underground metro Line 3,” he noted of ATM’s IP system, which was launched in 2010. “The surveillance system is now in operation on Lines 1 and 2 and has enabled ATM to install more cameras at more locations, providing better coverage and improving passenger security. The migration was carried out while the legacy network continued to operate which reduced disruptions during the installation.”
Railway communications chugs ahead since, after all, the trains must run on time.