Cellular Modem VPN Networking in Practice: Performance Comparison of IPSec and OpenVPN in Industrial Scenarios

Under the wave of Industry 4.0 and intelligent manufacturing, the number of Industrial Internet of Things (IIoT) devices has grown exponentially. The security, real-time performance, and stability of data transmission have become core pain points for enterprises in their digital transformation. According to statistics, 70% of global industrial network attacks stem from vulnerabilities in the data transmission process, while the latency and packet loss rate of traditional public network transmissions result in a more than 40% increase in equipment failure response times. Against this backdrop, VPN networking technology based on cellular modem  has emerged as a key solution for addressing the challenges of secure industrial data transmission. This article will provide an in-depth analysis of the advantages and disadvantages of IPSec and OpenVPN in industrial scenarios from three dimensions: technical principles, performance comparisons, and practical applications, offering decision-making bases for enterprise technology selection.

1. The Core Value of Cellular Modem VPN Networking: Addressing Three Major Pain Points

1.1 Data Security: From "Running Naked" to "Encrypted Tunnels"

In industrial settings, sensitive information such as PLC control commands, sensor data, and process parameters, if intercepted or tampered with, can lead to equipment malfunctions, production accidents, or even the leakage of trade secrets. VPNs establish logically isolated encrypted channels over public networks through tunneling technology, ensuring that data is transmitted only between authorized devices. For example, an automobile manufacturing enterprise used VPN networking to encrypt and transmit welding robot data from locations across the country back to its headquarters, reducing the risk of data leakage by 90%.

1.2 Cross-Domain Networking: Breaking Physical Boundary Limitations

Traditional industrial networks rely on dedicated lines or fixed IPs, which are costly to deploy and lack flexibility. VPNs support dynamic IP access and multi-protocol encapsulation, enabling flexible networking across regions and operators. For instance, an oil enterprise used VPNs to interconnect the SCADA systems of remote oil wells with its headquarters monitoring center, saving over 60% in dedicated line costs while supporting multi-network switching between 5G/4G/WiFi to ensure zero interruptions in data transmission.

1.3 Remote Operations and Maintenance: From "On-Site Presence" to "Cloud-Based Control"

Industrial equipment is widely distributed and difficult to maintain, with traditional operations and maintenance requiring on-site engineer intervention, resulting in low efficiency. VPNs, combined with two-factor authentication and firewall联动, allow engineers to securely access equipment remotely through encrypted channels for operations such as parameter adjustments and firmware upgrades. A power company used VPN networking to reduce the operations and maintenance response time for high-voltage cable monitoring equipment from 4 hours to 10 minutes, saving over 2 million yuan in annual labor costs.

2. Comparison of IPSec and OpenVPN Technical Principles: The Trade-off Between Security and Flexibility

2.1 IPSec: The "Golden Bell" of Enterprise-Grade Security

Technical Architecture: IPSec (Internet Protocol Security) is a network-layer encryption protocol that achieves data integrity verification, confidentiality protection, and anti-replay attacks through AH (Authentication Header) and ESP (Encapsulating Security Payload). Its core advantages include:

• End-to-End Encryption: Data is encrypted from the cellular modem source to the central central server room throughout the entire process, with intermediate nodes unable to decrypt it.
• Hardware Acceleration Support: Industrial routers are equipped with dedicated IPSec chips, resulting in encryption/decryption delays of less than 5ms.
• Strong Protocol Compatibility: Supports industrial protocols such as Modbus TCP and OPC UA for encapsulation within VPN tunnels.
  Typical Scenarios: Power monitoring, oil and gas pipelines, and other scenarios with extremely high security requirements. For example, a power grid enterprise used IPSec VPNs to encrypt and transmit high-voltage substation data back to its headquarters, achieving a "data not landing" transmission mode that meets the requirements of Class 3 Protection 2.0.

2.2 OpenVPN: The "Light Cavalry" of Flexible Deployment

Technical Architecture: OpenVPN is an application-layer protocol based on SSL/TLS that achieves data encryption and identity authentication through the OpenSSL library. Its core advantages include:

• Cross-Platform Compatibility: Supports multiple operating systems such as Linux, Windows, and Android, adapting to various cellular modems.
• Dynamic Port Networking: Can bypass operator port blocking, adapting to complex network environments.
• Rich Open-Source Ecosystem: Enterprises can customize encryption algorithms (e.g., AES-256) and authentication methods (e.g., digital certificates) according to their needs.
  Typical Scenarios: Mobile device monitoring, temporary project networking, and other scenarios with high flexibility requirements. For example, a construction machinery enterprise used OpenVPN to transmit cellular modem data from excavators back to the cloud in real-time, supporting millisecond-level latency transmission over 5G networks to meet predictive maintenance needs.

3. Performance Comparison: Practical Testing from the Lab to Industrial Sites

3.1 Security: IPSec Has a Slight Edge, but OpenVPN Can Be Customized for Enhancement

• Encryption Strength: IPSec defaults to AES-128/256 encryption, complying with FIPS 140-2 standards; OpenVPN supports encryption of the same strength but requires enterprise configuration.
• Identity Authentication: IPSec relies on pre-shared keys or digital certificates, with a strict authentication process; OpenVPN supports multi-factor authentication with usernames/passwords + dynamic tokens, offering higher flexibility.
• Anti-Attack Capability: IPSec has built-in anti-replay attack mechanisms to defend against DDoS attacks; OpenVPN requires firewall rules to achieve similar functionality.
  Practical Recommendations: For scenarios with extremely high security requirements (e.g., nuclear power plant monitoring), prioritize IPSec; for scenarios with high flexibility requirements (e.g., temporary construction site monitoring), choose OpenVPN and enhance security through customization.

3.2 Real-Time Performance: OpenVPN Has Lower Latency, while IPSec Offers Greater Stability

• Latency Testing: Under 4G networks, OpenVPN has an average latency of 30ms, while IPSec has 50ms (data source: practical testing by an industrial router manufacturer).
• Packet Loss Rate: IPSec reduces data packet processing time through hardware acceleration, with a packet loss rate below 0.1%; OpenVPN's packet loss rate may rise to 0.5% in high-concurrency scenarios.
• Network Switching: IPSec supports multi-link redundancy, automatically switching to backup links in case of primary link failures; OpenVPN relies on upper-layer applications for similar functionality.
  Practical Recommendations: For scenarios with high real-time requirements (e.g., industrial video surveillance), prioritize OpenVPN; for scenarios with high stability requirements (e.g., cross-regional factory data aggregation), prioritize IPSec.

3.3 Deployment Costs: OpenVPN is More Economical, while IPSec Requires Hardware Investment

• Equipment Costs: IPSec requires dedicated industrial routers (priced around 5,000-20,000 yuan), while OpenVPN can be implemented through software (reducing costs by over 60%).
• Operations and Maintenance Costs: IPSec configuration is complex and requires professional network engineers for maintenance; OpenVPN provides a visual management interface, improving operations and maintenance efficiency by 40%.
• Expansion Costs: IPSec supports dynamic routing protocols (e.g., OSPF) for easy network scale expansion; OpenVPN requires additional nodes for expansion, with costs increasing with scale.
  Practical Recommendations: Small and medium-sized enterprises or temporary projects should prioritize OpenVPN; large enterprises or long-term projects can invest in IPSec to reduce long-term operations and maintenance costs.

G771-E

4G Cat.1, 2GRS485,RS232MQTT, SSL/TLS

4. Practical Case Study: How USR-G771 Cellular Modem Empowers Industrial VPN Networking

In a smart factory project, a customer needed to transmit data from over 1,000 PLCs distributed across the country back to the cloud in real-time while meeting the following requirements:

• Security: Data transmission must comply with Class 3 Protection 2.0 requirements.
• Real-Time Performance: Control command latency must be below 50ms.
• Flexibility: Support for multi-network switching between 5G/4G/WiFi.
  Solution:
• Equipment Selection: Adopt USR-G771 4G Cat-1 cellular modems from USR IoT, supporting dual protocol stacks of IPSec/OpenVPN and built-in hardware encryption chips.
• Networking Architecture:
  • Core Network: Deploy an IPSec VPN server to achieve end-to-end data encryption.
  • Edge Network: Cellular modems establish temporary channels through OpenVPN, supporting millisecond-level latency transmission over 5G networks.
  • Management Platform: Integrate two-factor authentication and firewall rules to prevent unauthorized access.
    Effect Verification:
• Security: Certified by the National Information Security Evaluation Center, reducing the risk of data leakage by 95%.
• Real-Time Performance: Average control command latency of 35ms, meeting industrial automation requirements.
• Cost: Saved 70% in deployment costs compared to traditional dedicated line solutions, improving operations and maintenance efficiency by 50%.

5. Technology Selection Recommendations: Matching Technical Solutions to Scenarios

6. The Art of Balancing Security and Flexibility

The core of cellular modem VPN networking lies in balancing security and flexibility according to scenario requirements. IPSec is like a "heavily armored knight," safeguarding critical infrastructure with high security; OpenVPN is akin to an "agile assassin," responding to complex network environments with flexibility. Enterprises need to select the most suitable technical solution based on their scale, budget, and business needs.

Take Action Now: If you are facing challenges in secure industrial data transmission, contact USR IoT experts to obtain a free trial of the USR-G771 cellular modem and experience the practical effects of the IPSec/OpenVPN dual protocol stack!