ISDS Backbone Network Solutions for Rail Transit

Solution Overview

High-reliability, high-bandwidth, high-value dual-network backbone for metro ISDS

MRD delivers high‑reliability, high‑bandwidth, and cost‑effective communication transmission solutions for the rail transit Information Service Distribution System (ISDS) backbone network. With a deep understanding of the industry’s core requirements for security, reliability, guaranteed bandwidth, and scalability – and backed by years of research into service traffic patterns – we propose an innovative dual‑network architecture: a “voice and low‑speed data network” alongside a “broadband data network.”

Industry Challenges

As rail communications backbones evolve, bandwidth surge and unbalanced traffic mix create common pain points:

Bandwidth demand continues to rise
The business bandwidth of each subsystem continues to increase, and the transmission system is forced to adopt 10Gbps level bandwidth.
The proportion of Ethernet services is too high
The required bandwidth is 80% and for Ethernet services, but for 20% of non-Ethernet services, 100% 10g is assumed for this, and the use of backbone bandwidth is unreasonable.
Operation and maintenance system fragmentation
Traditional MSTP/SDH and hanging switches belong to different equipment systems. Maintenance requires professional transfer personnel, which is integrated into this high.
High safety protection pressure
As a for subsystem convergence point, the transmission backbone network faces three major security challenges: network structure, system vulnerabilities, and protocol risks.

MRD Dual-Network Scheme

The voice/low‑speed data network and the broadband data network handle different traffic classes, each performing its designated role.

Core program for ratio:

plan	Technical route	bandwidth	Applicable business
Traditional/Mainstream Plan	SDH / MSTP / PTN / OTN	2.5Gbps / 10Gbps	Mixed bearing of all services
MRD Recommended Solution	SDH/MSTP (Voice/Low Speed) + 10g Industrial Ethernet (Broadband Data)	2.5Gbps + 10Gbps	Classification bearer, each division's position

Our solution has provided for multiple lines to transmit backbone network design references, and the core product TNM6000 modular core industrial switch supports three-level security protection and HSR/PRP zero-loss redundant to meet the future all-IP trend.

1. Transmission backbone system responsibilities and bearer services

The transmission backbone system task is to provide a unified network access platform for different business types. In addition to the signaling system, subsystems can rely on the transmission system achieves inter-site data communication:

Closed circuit television system (CCTV)
Integrated Surveillance System (ISCS)
Ticket Collection System (AFC)
Broadcasting System (PA)
Office Network System (OA)

2. MRD dual network solution: voice/low speed network + broadband data network

2.1 Industry background and technology evolution

the evolution of the backbone network technology of the rail transit communication system has always been the primary consideration for security stability, bandwidth can guarantee, and scalability. The technical solution has evolved to:

traditional solution

When the program

ideal solution

2.2 Common pain points in the industry

The business bandwidth requirements of each subsystem continue to increase, resulting in the transmission system having to adopt 10Gbps level bandwidth

The required bandwidth is 80% and for Ethernet services, resulting in unreasonable bandwidth usage of the for transmission backbone (for 20% non-Ethernet services, assuming 100% 10g for this)

2.3 MRD Dual Network Solution

Based on the in-depth study of the bandwidth types and bandwidth types of each service of the for communication system, MRD™ Meridian ® proposes two network solutions: "Voice and low-speed data network + broadband data network":

network	Technical route	bandwidth	Bearing business
Voice and low-speed data networks	SDH/MSTP	2.5Gbps	Narrowband services with extremely high voice, low-speed control signals, and real-world requirements
Broadband data network	10GLayer-3Industrial Ethernet Switch	10Gbps	CCTV, AFC, OA, etc. Ethernet services (80% traffic)

Solution advantages:

More cost-effective: MSTP 2.5g + 10g Industrial Ethernet, lower than this for 10Gbps SDH/MSTP/PTN solutions

Stronger can management: Broadband data network adopts industrial Ethernet, and hung switches for the same type of equipment, unified management

More can scalability: IPstandard will not change, strong investment protection

3. Industrial Ethernet VS MSTP/SDH:

for Bidimension	10g Industrial Ethernet Backbone	MSTP/SDH transport backbone
Purchase into this	Low	high
Maintain as this	Low-and-hanging switches are a class of equipment, and IT maintenance talents can be managed	High- and connected switches are two types of equipment and require professional transmission personnel (a failure point requires multi-professional personnel)
Device can Reliability	High — compliant with industrial standard, adaptable to various environments, long MTBF	Low — non-industrial standard, weak environmental adaptability, short MTBF
IP message transmission capability	high	Low
Non-IP message transmission capability	Low	high
Device types	Very many, mature technologies	Less (inconsistent for each manufacturer and each when period)
investment protection	Strong — IPstandard long-term stability	Weak — Fast device update, mixed devices in different when periods
Technology development trends	All-IP is the development trend in various industries	Unknown direction

for Ethernet services account for the dominant (≥ 80%) rail-crossing transmission backbone network, the 10g industrial Ethernet bearer broadband data + SDH/MSTP bearer narrowband voice dual network solution is the optimal balance between technology, this, and operation and maintenance.

4. MRD Level 3 Safety Protection Module (for transport backbone)

The transmission backbone network serves as a convergence point for all subsystems, and faces three major security challenges: network structure risk, system vulnerability risk, and protocol risk.

Security risk category	Detailed description
Network structure risk	Complex structure, multiple subsystem interfaces, lack of regional isolation; lack of intrusion detection and security self-test mechanism; lack of data flow control and access audit between subsystems
System vulnerability risk	Transmission terminal equipment operating system vulnerability; country controller stored in after door risk
Network protocol risks	TCP/IP has inherent security flaws; industrial control protocols lack authentication/authorization/encryption; traditional IT firewalls cannot recognize industrial control protocols; anti-virus software affects system stability

Modular three-tier security protection architecture

MRD provides can be embedded with the TNM6000 Core Switch Level 3 Security Module:

protection hierarchy	Core functions	Technology achieves
Smart protection	Only allow specific format data passes; for all access data flows for control protection	Packet format, key bits, flow depth query and control
Audit testing	Illegal access monitoring; network for auditing	Real when detects abnormal access and records the entire network access log
Host protection	Deny viruses/Trojans; Deny unauthorized USB access; Deny unauthorized processes; Deny unauthorized network access	Terminal whitelist, USB port control
data isolation	One-way transmission characteristics to ensure that the packet has no one-way passes and no feedback; prevent important data leaks	One-way gatekeeper technology, data diode

for Customer Value

in the transport backbone level, that is, achieves area isolation, intrusion detection, protocol filtering, one-way data transmission, etc. Warranty 2.0 for critical information infrastructure requirements.

5. Generation backbone redundant technology: HSR/PRP (IEC62439-3)

The International Electrotechnical Commission (IEC) defined the HSR (Highly Reliable Seamless Redundant) protocol in passes IEC62439-3-5 in 2012.

Core capability

protocol	standard	mechanism	performance
HSR	IEC62439-3-5	Dual send and receive (same when sent in both directions along the loop, first to packet selected at the receiving end)	Zero packet loss, zero switching
PRP	IEC62439-3-4	and row redundant (node is connected to A/B dual network, same IP/Mac, same send when)	Either of the two networks completely fails, with zero impact on business

PRP
PRP and line redundant protocols

Advanced application: HSR + PRP hybrid networking

The backbone layer adopts HSR ring network (high bandwidth, zero switching)

The access layer adopts PRP (dual network isolation)

Further: The software achieves A/B network switching, sinks to the hardware layer to complete, releases CPU resources, and further shortens the interval between interruptions.

for Customer Value

the for fully automatic operation line (GoA3/4) provides transmission backbone layer zero break guarantee.

Industrial Ethernet

Industrial Wi-Fi

Industrial Cellular

Industrial IoT

Industrial PON

Industrial Power Supply