CAN, LIN, Ethernet: Why a Single Car Generates 2–5 Million Messages/Day

CAN, LIN, AND ETHERNET:

WHY A SINGLE CAR GENERATES 2–5 MILLION MESSAGES PER DAY

When the automotive world speaks of “vehicle data,” most people imagine simple telemetry – GPS coordinates, speed, maybe battery state. Reality is radically more complex.

A connected vehicle produces a torrent of internal messages, millions per day, long before any telematics system touches the data.

This is the hidden world of in-vehicle networks.

1. Understanding CAN: The Nervous System of the Vehicle

CAN (Controller Area Network) is the most important communication protocol inside a car. It carries messages related to:

  • Brake pressure
  • Accelerator position
  • Steering angle
  • Wheel speed
  • Gear position
  • Engine torque
  • Battery state
  • ADAS sensor fusion outputs

A single brake application can generate dozens of messages. Multiply that by all driving behaviors—and then multiply again by all sensors operating in parallel.

This is why 2–5 million messages/day is normal. (Confirmed in x18’s technical documentation.)

2. Why Vehicles Generate So Much Data
Reason 1: Real-time deterministic control

Many ECUs send the same type of message every 10 – 20 milliseconds, regardless of vehicle state.

Reason 2: Redundancy for safety

Critical signals are repeated multiple times to ensure reliability.

Reason 3: Sensor fusion for ADAS

Modern cars read from radar, cameras, ultrasonic sensors, and inertial measurement systems simultaneously.

Reason 4: Software-defined logic

SDVs centralize data, meaning more stream consolidation, more duplication, more logging.

Telematics systems only capture a tiny fraction of this internal data – but that fraction is enough to enable predictive maintenance, risk scoring, and behavioral analytics.

3. Automotive Ethernet: The Bandwidth Revolution

As vehicles move toward L2+/L3 autonomy, CAN no longer suffices.

Automotive Ethernet enables:
  • High-throughput ADAS processing
  • Camera-to-ECU data flows
  • High-resolution sensor networks
  • Data-hungry autonomy algorithms

This increases message volume even more.

4. How Telematics Turns Raw Data Into Intelligence

OBD-based devices like OBDx or OEM TCUs tap into CAN and Ethernet networks to extract key signals:

  • Engine performance curves
  • Brake degradation patterns
  • Torque fluctuations
  • Battery anomalies
  • Steering/handling irregularities
  • EV thermal management patterns

Platforms like ForeFix convert these signals into predictive maintenance insights.

Telematics does not create data. It reveals the massive river of information already flowing inside the car.

5. Why This Matters for Cybersecurity

High-volume messaging creates complexity. Complexity creates an attack surface.

  • CAN is unencrypted
  • Messages lack authentication
  • ECUs trust each other implicitly
  • A compromised node can impersonate others

Understanding the data flow is essential to securing it.

This is why tools like VulnCar and monitoring systems like VSOC are critical – they map, analyze, and protect the internal network’s behavior.

6. Conclusion

A vehicle is not “becoming” a data machine.  It has always been one.

The difference in 2025 is that the world finally has:

  • The telematics to read it
  • The AI to interpret it
  • The cybersecurity to protect it

And the companies capable of delivering all three – such as x18 – will shape the future of connected mobility.