Network Infrastructure in Public Transport Vehicles: Proof of Concept

What is the Current State of the Art?

As with any new development, it makes sense to first find out about the state of the art for new network projects in public transportation. Professional associations such as the International Public Transport Association UITP and the Initiative for Interoperability ITxPT offer support on state-of-the-art standardized network architectures.

Create a Network Concept: The Specifications

On the way to the optimal network infrastructure, questions need to be answered such as:

• Which components belong in the network?
• For what purpose will they be used?
• What functionalities should the components have?

The exact project or the individual component specifications are recorded and defined in more detail in a requirements specification. In other words, the requirements for the network should be described in detail. Using IP cameras as an example, typical requirements would be the number of cameras to be installed per vehicle, the recording duration and whether the video data is to be streamed live or merely stored.

Defining the Network: Details

For an IP network concept to work, it should be planned down to the last detail. All components should be determined, especially their number and how they are physically connected to each other. It is also important to define how addressing is to take place within the network: by means of a central DHCP server, several local DHCP servers or statically. Also important: whether the network should be segmented so that only certain end devices can exchange data with each other. This is particularly relevant for end devices that process sensitive data ( Wi-Fi, open payment systems).

Select components: Compatibility

Compatibility refers to both the physical connections and the software interfaces. This enables manufacturer-independent integration and interchangeability of all components. When selecting suitable components, standards such as IBIS-IP (VDV 301) and the ITxPT label provide orientation to ensure the interoperability of the components.

Depending on the defined network architecture, there are different network technology requirements for end devices. If the network is to be segmented by the use of VLANs, the requirement for VLAN-capable end devices is derived from this. The same applies to the distribution of IP addresses: If IP addresses are to be distributed via a DHCP server, the end devices must support the function of a DHCP client.

Overall, it should be noted that the choice of suitable end devices contributes to a simple and fast implementation of the IP network infrastructure.

Laboratory Testing: The First Practical Test

In order to become familiar with the selected components and to test them in practice, a laboratory test is carried out. This involves testing the network infrastructure in interaction with the end devices. In detail, settings on router and switch as well as end devices are to be made in such a way that you comply with the specifications of the network planning.

Checklist:

• Make settings on network infrastructure components
• Make settings on the on-board computer and end devices
• Test with productive data (e.g., camera stream on screen)
• Backup configuration files of all components

Documentation: Recording the Plan

The proof of concept is concluded with detailed documentation of what has been achieved so far, so that the next phase can proceed smoothly. This includes:

• Overview of all devices
• Wiring diagram
• IP addresses
• Configurations of individual devices

All of these measures are intended to enable a mass rollout through a one-to-one transfer. The implementation of the network architecture should be as simple and error-free as possible.

Finalization: Final votes

The Proof of Concept phase of a network infrastructure project for the bus or train is finalized with a few final summaries and votes. Checklists make IP network construction or rollout easier. Trobleshooting lists are also useful to create. Last but not least, these must be coordinated with all those involved, such as network architects, the IT team, vehicle technicians and fleet managers.