Railcar Network System Remote Maintenance Architecture
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Solution Overview
Problem
In railcar networks, maintenance work is labor-intensive due to the need for physical access to update software or acquire logs from apparatuses, and the existing network architecture increases inter-car network traffic and complicates address management, compromising security.
Innovation Solution
A network system with intra-car and inter-car networks, where routers perform address translation and a maintenance transmission path forms unit allows external terminals to connect to intra-car networks without using the network address translation of the maintenance target's car, enabling remote maintenance and reducing inter-car network traffic and security risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If monitoring devices communicate with each apparatus in all cars through the inter-car network, then apparatus information can be collected from all cars, but inter-car network traffic increases and throughput decreases
Solution Approach 1:
The network is segmented into intra-car networks (local) and inter-car networks (global). Each car has its own intra-car network where monitoring devices communicate with apparatuses locally, avoiding saturation of the inter-car network. Only necessary information is transmitted through the inter-car network between head car and other cars.
2Ease of operation
If all apparatuses are made accessible from other cars through the inter-car network, then remote access is enabled, but security is compromised
Solution Approach 1:
Different security levels are applied to different network segments. The intra-car network allows local access to apparatuses, while the inter-car network restricts access to only monitoring devices. This localized security approach enables remote monitoring while preventing unauthorized access to apparatuses.
3Ease of repair
If a mobile external terminal connects directly to the intra-car network for maintenance, then software updates and log acquisition are enabled, but physical access to each car is required increasing labor
Solution Approach 1:
A maintenance server is introduced as an intermediary between the external terminal and the intra-car network. The external terminal connects to the maintenance server through the inter-car network, which then provides access to the target car's intra-car network. This eliminates the need for physical access to each car while maintaining full maintenance capability.
4Adaptability or versatility
If the NAT table is updated to include all apparatuses for address translation, then comprehensive address management is achieved, but management labor increases
Solution Approach 1:
The NAT function is extracted from individual car routers and centralized in the head car router. Only monitoring devices, not all apparatuses, require address translation through the NAT table. This significantly reduces the number of entries needed in the NAT table and simplifies management while maintaining comprehensive address management for monitoring purposes.
Data Source
AI summary
The present invention provides a network system of a railcar, the network system being capable of efficiently performing maintenance work. One example of the network system of the railcar of the present invention includes: intra-car networks (N1 to N3) to which first and second apparatuses are connected; an inter-car network (NA) for transmission of information between the apparatuses mounted on different cars; routers (R1 to R3) each provided and connected between the corresponding intra-car network (N1 to N3) and the inter-car network (NA) and each including a network address translation portion configured to mutually convert a private address of the first apparatus and an IP address of the inter-car network (NA); and a maintenance transmission path forming unit configured to form a transmission path through which the transmission and reception of the information are performed between a maintenance terminal (5) and a maintenance target apparatus selected from the first and second apparatuses, the transmission path not passing through the network address translation portion of the car on which the maintenance target apparatus is mounted.