Imagine that industrial routers are like “information couriers” in industrial sites. To enable two couriers to pass packages (data) to each other, several things need to be clarified: How do they find each other? Through what “road” (network) is it transmitted? What does the “package” being delivered look like (as per the agreement)?
Direct communication based on IP address (the most common)
Working principle: This is the most fundamental and widely used method. Just as we need an IP address to access the Internet, each industrial router is assigned a unique IP address. When one router needs to communicate with another, it “calls” the other party through this IP address and sends data packets.
Working principle: This is the most fundamental and widely used method. Just as we need an IP address to access the Internet, each industrial router is assigned a unique IP address. When one router needs to communicate with another, it “calls” the other party through this IP address and sends data packets.
Implementation method:
In the same network segment: If two routers are connected to the same local area network (LAN) or connected to the same subnet through devices such as switches, and the correct IP addresses and subnet masks are configured, they can directly access each other through their respective IP addresses.
Different network segments/wide area networks (Wans) : If routers are located in different places, or one is within a local area network and the other is at the other end of the Internet, routing needs to be configured. This usually involves:
Static routing: Manually configure the path to the target network (the network where the other router is located) on the router.
Dynamic routing protocols: such as OSPF, BGP, etc., enable routers to automatically learn and exchange routing information with each other, dynamically adapting to network changes.
Application scenarios: Device data collection and forwarding, simple remote monitoring, and device interconnection within the local network.
Working principle: When two routers need to communicate securely through an insecure public network, such as the Internet, a VPN is the preferred solution. It can establish an encrypted and logically dedicated channel in the public network.
Implementation method:
IPSec VPN: Configure the same IPSec policy (pre-shared key or certificate authentication, encryption algorithm, authentication algorithm, etc.) on two routers to establish a point-to-point secure tunnel. Data will be encrypted before transmission to ensure confidentiality and integrity.
SSL/TLS VPN: Typically used for remote access, it allows one router to securely connect to another router or network that serves as a server as a client.
Application scenarios: Secure data transmission between remote factories/equipment, remote maintenance access, and network interconnection of cross-regional branches.
Dedicated link technologies (such as point-to-point leased line)
Working principle: If there are extremely high requirements for real-time performance, stability and bandwidth of communication, and the two routers are in fixed geographical locations, consider using dedicated physical lines provided by the operator, such as point-to-point leased line (leased line).
Implementation method: The two routers are directly physically connected through the dedicated lines provided by the operator. The configuration is relatively simple, mainly involving the configuration of interface IP addresses and possible link layer protocols (such as PPP) on the router.
Application scenarios: Critical control signal transmission sensitive to delay, high-speed data buses in large factories, banks/finance and other scenarios with extremely high reliability requirements.
Wireless Mesh/ AD hoc network technology
Working principle: For scenarios where wiring is difficult or high mobility is required, some industrial routers support wireless Mesh or self-organizing network technology. Routers can dynamically establish and maintain network connections wirelessly, and data can reach the destination through multi-hop forwarding.
Implementation method: No complex wiring is required. Just configure the routers that support this function in the same Mesh network, and they will automatically discover neighbors and establish routes.
Application scenarios: Wireless access for mobile devices (such as AGVs, inspection robots), network coverage for temporary construction sites/exhibitions, remote areas or regions with difficult wiring.
Which way to choose?
Distance: Local or remote?
Security requirements: Is encryption necessary?
Bandwidth and latency requirements: How high are the requirements for data transmission speed and response time?
Cost budget: The deployment and maintenance costs of different technologies vary greatly.
Environmental complexity: Is the network topology a simple point-to-point or a complex mesh structure?
The connection and communication between industrial routers is the foundation for achieving industrial automation and Internet of Things applications. From simple IP communication to secure VPN, and then to high-speed dedicated links and flexible wireless AD hoc networks, multiple technical approaches provide rich choices for different application scenarios. Understanding the working principles and applicable scenarios of these technologies is essential for better designing and deploying stable and reliable industrial networks.