Press Releases
Comparing Automotive Protocols
October 25, 2024
| FACTOR | LIN | CAN | ETHERNET | |
|---|---|---|---|---|
| COMMUNICATION CHARACTERISTICS | ||||
| Access Control | Medium Access Control | Master-slave (single master, multiple slaves) | Multi-Master CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) |
Multi-Master CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) |
| Bus Conflicts | Master uses arbitration process to resolve bus conflict | Resolved by arbitration on message ID | Resolved by collision detection and backoff | |
| Transmission | Communication Type | Serial, synchronous | Serial, asynchronous | Serial, asynchronous |
| Message Transmission | Deterministic | Deterministic | Non-deterministic, packet-switched | |
| Triggered Technique (event / time triggered) | Time-triggered | Time-triggered | Event-triggered | |
| Message Transmission Latency | Low, predictable | Low, predictable | Low | |
| Latency Jitter | Constant | Load dependent | Typically low | |
| Efficiency | Bus Utilization Efficiency (excluding idle time) | Typically low (10-40%) due to simple protocol | High (up to 100% for critical messages) | High |
| Quality of Service | Limited | Higher due to prioritization of messages | Supports QoS features in higher layers | |
| Error detection and correction methods | Basic parity checks | CRC (Cyclic Redundancy Check) | CRC and additional methods in higher layers | |
| PERFORMANCE | ||||
| Speed | Speed | Slow | Medium | Fast |
| Typical Bus Speed (bit/sec) | Up to 20Kbps | 33Kbps – 1 Mbps | 10 Mbps – 100 Gbps | |
| Capacity | Data and Frame Size | 1 – 8 bytes payload 44 bits overhead |
0 – 8 bytes payload 47 bits overhead (std ID) 67 bits overhead (ext ID) |
Large (up to 1500 bytes standard, jumbo frames possible) |
| PHYSICAL LAYER & MEDIA | ||||
| Connection Details | Cable Type | Unshielded twisted pair | Shielded twisted pair | UTP, STP, fiber optic |
| Cable core | Copper | Copper | Copper, fiber optics | |
| No. of Lines Required | 1 | 2 | 2, 4, or 8 depending on Ethernet variant | |
| Max. Cable Length | 40 meters (theoretically) – typically 10 – 20 meters | 40 meters (at 1 Mbps) | 100 meters (Ethernet over copper), kilometers over fiber | |
| Energy | Power Consumption | Very low | Low | Varies, higher than CAN/LIN for high speeds |
| Nodes | Number of Nodes | Up to 16 nodes | 64 to 128 nodes | Thousands of nodes (depends on Ethernet switches) |
| Possible Topologies | Linear (bus) | Linear (bus), star | Bus, star, ring | |
| SCALABILITY & EXTENSIBILITY | ||||
| Growth Potential | Extensibility | Limited | Moderate | High |
| Scalability | Limited | Good | High | |
| Reliability | Basic | High | High | |
| Interoperability | Low | Medium | High | |
| Security | Basic | Basic | Basic | |
| COST & COMPLEXITY | ||||
| Cost Factors | Overall Cost | Low | Moderate | High |
| Implementation | Implementation Complexity | Low | Moderate | Complex |
| Implementation Cost | Low | Moderate | High | |
| USAGE | ||||
| Applications | Use Cases | Sensor / actuator interface to a master ECU (doors, mirrors, windows, motors, ABS) | Automotive control networks, industrial automation (Electric seats, mirrors, tailgate, wiper control) | General-purpose networking, IoT, industrial automation |
| FACTOR | J1939 | UDS | |
|---|---|---|---|
| COMMUNICATION CHARACTERISTICS | |||
| Transmission | Communication Type | Serial, asynchronous (over CAN) | Serial, asynchronous (over CAN or other transport layers) |
| Message Transmission | Deterministic message priority | Non-deterministic | |
| Triggered Technique | Event-triggered | Event-triggered (on request) | |
| Message Transmission Latency | Low, predictable | Varies, typically low (depends on transport layer) | |
| Latency Jitter | Low (due to CAN message priority) | Low to medium (depends on transport layer) | |
| Efficiency | Bus Utilization Efficiency | High, especially for critical messages | Moderate (diagnostic traffic infrequent but potentially high) |
| Quality of Service | Higher due to message prioritization | Limited (depends on transport) | |
| Bit Coding | NRZ w/ bit stuffing (CAN-based) | NRZ (based on underlying transport, e.g., CAN) | |
| Error detection | CRC on CAN layer | Depends on transport (e.g., CAN’s CRC) | |
| SCALABILITY & EXTENSIBILITY | |||
| Growth Potential | Extensibility | High (supports complex networks) | Moderate (new diagnostic services) |
| Scalability | High (multiple segments) | Limited by protocol overhead | |
| Reliability | High | High (depends on protocol like CAN) | |
| Interoperability | Medium | Low (diagnostics-specific) | |
| COST & COMPLEXITY | |||
| Cost Factors | Overall Cost | Moderate to high | Moderate |
| Implementation | Complexity | Complex (network control needs) | Moderate (diagnostic routines) |
| Implementation Cost | Moderate to high | Moderate (diagnostic equipment) | |
| INDUSTRY SUPPORT & STANDARDIZATION | |||
| Acceptance | Industry | Widely accepted (trucks, heavy machinery) | Widely used (vehicle diagnostics) |
| USAGE | |||
| Applications | Use Cases | Fleet management, engine control | Vehicle diagnostics (OBD-II, ECU) |