Home > Moxa releases dynamic ring coupling for inter-consist network redundancy

Moxa releases dynamic ring coupling for inter-consist network redundancy

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Amtrak’s Empire Builder departs Chicago for Seattle and Portland as multiple units travelling together as a single train for most of the journey. However, when the train reaches Spokane, the multiple-unit consists that make up the train split into two shorter trains, with one continuing on to Seattle and the other to Portland. The splitting of the trains mid-journey enables railway operators to utilise resources and schedule long-distance passenger services for multiple markets in a more efficient and flexible way. Moreover, the benefits afforded by multiple-unit (MU) trains are not limited to long-distance inter-city railway lines.

Reorienting consists from separate trains mid-journey also allows train operators for both inter-city and metropolitan mass rapid transit rail systems to save energy and more efficiently allocate resources. For instance, the consists can be reconfigured in metro systems to have fewer cars during off-peak hours while adding more cars during peak travel hours to optimise energy use and operational costs.

Since the train consists that comprise a multiple-unit train may need to be rearranged mid-journey, it can be challenging to ensure redundancy for multiple-unit Ethernet consist networks. A key challenge lies in manually configuring network settings when train consists are reoriented, which requires sufficient knowledge of Ethernet protocols. In the absence of such knowledge, the additional time and labour costs must be factored into the equation. During reorientation, each consist may encounter security issues if the network system needs to restart due to a topology change. This disruption in onboard services, such as passenger information systems and passenger Wi-Fi access, is also likely to upset many discerning passengers and hurt overall customer satisfaction.

Existing redundancy methods

Solutions that can be leveraged to provide railway automation networks and multiple-unit Ethernet Consist Networks (ECN) with redundancy include traditional ring coupling, Rapid Spanning Tree Protocol (RSTP), and Dynamic Ring Coupling. Although each of these has its own drawbacks and benefits, Dynamic Ring Coupling offers a better solution for the unique redundancy requirements of multiple-unit ECNs.

If the Ethernet switches on a train could determine automatically the specific ports to set as redundant ports and those to set as normal ports, it is possible to overcome the problems associated with traditional ring coupling and RSTP. In Dynamic Ring Coupling (DRC), two port pairs in each ring will automatically identify which pair should be set to redundant mode, without requiring any configuration from the operator. DRC allows train operators to rapidly connect and reconnect train consists, streamlining operational efficiency and minimising configuration errors.

When two Moxa Ethernet switches are connected as ring coupling switches, dynamic ring coupling identifies which port should be set as the inactive, blocked port without any assistance from the operator. This allows the train to enjoy the fast redundancy of Moxa's advanced ring redundancy technology, while still being flexible enough to re-deploy again.

DRC automatically configures the network's redundant ring in less than one second, free from human error and interference from intra-consist network devices used for CCTV surveillance, Wi-Fi access, and passenger information systems

Redundancy that works for rail

High network availability, reliability, and efficiency are key objectives of railway operators when deploying multiple-unit Ethernet consist networks for long-distance trains. Besides offering the speedy, automatic configuration for onboard Ethernet switches when consists are rearranged mid-journey, the Dynamic Ring Coupling technology provided on the Moxa EN 50155 managed Ethernet switches guarantees inter-consist network recovery in under one second, and even faster intra-consist recovery in 20 milliseconds.

Unlike RSTP, Dynamic Ring Coupling does not disrupt intra-consist networks during reorientation. This enables all the Ethernet network services available on long-distance trains such as CCTV surveillance, Wi-Fi access, passenger information systems, public announcement systems, and more to be seamlessly enjoyed even when coupling switches are rearranged mid-journey.

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