Comparison
ASG compared with the in-vehicle networks in use today
A side-by-side comparison of ASG against CAN / CAN-FD, LIN, FlexRay and Automotive Ethernet, on topology, timing, determinism under load, harness impact and fault handling.
CAN, LIN, FlexRay and Automotive Ethernet are communication protocols: rules for moving bytes between control units. ASG is an architecture, where the protocol, the real-time operating system and the ring channel are one system, and the shared object is the vehicle’s state rather than a stream of messages.
So a fair comparison is not ASG against any one bus. It is one synchronous architecture against the mix of buses and gateways a vehicle uses today, judged on what a control engineer has to live with: is the timing fixed, is the state shared, how much harness does it take, and what happens under load and under fault.
The matrix
| Dimension | CAN / CAN-FD | LIN | FlexRay | Automotive Ethernet | ASG |
|---|---|---|---|---|---|
| What it is | A communication bus. Control logic sits in the ECUs on top of it. | A low-cost communication sub-bus for slow body functions. | A communication bus with a time-triggered schedule layered on top. | A transport. IP networking for high-bandwidth links and the backbone. | A control architecture: protocol, real-time OS and ring channel as one system. |
| Topology | Linear multi-drop bus with short stubs and a termination resistor at each end. | One master with several slaves on a single shared wire. | One or two channels, wired as a bus, a star, or a hybrid. | Point-to-point links into switches; a star, or a ring of switches for the backbone. | Single ring routed through the vehicle volume; zones attach within a wire-length budget. |
| Medium | Dedicated differential twisted pair. Power is routed separately. | A single dedicated wire referenced to ground. Power routed separately. | Dedicated differential pair per channel. Power routed separately. | Dedicated single differential pair per link (100BASE-T1). Power routed separately, or PoDL. | Power and data on the same conductors (PLC over 12 / 24 / 48 V), or a twisted pair. |
| Media access | Non-destructive bit arbitration by identifier priority (CSMA/CR). | The master polls each slave in turn. No arbitration. | TDMA: fixed slots in a static segment, mini-slot contention in a dynamic segment. | Full-duplex point-to-point, so no media contention; queueing happens inside the switches. | Frequency-division. Each zone has its own carrier (a diad); no contention for the channel. |
| Timing model | Event-triggered. A frame is sent when a node has something to send. | Schedule-table driven by the master; slot period typically a few ms. | Global schedule you configure: a fixed cycle of static and dynamic slots. | Asynchronous by default; bounded only where 802.1 TSN scheduling is added and configured. | One global commit every 1 ms. Every zone updates in the same instant. |
| Determinism under load | Priority-dependent. Low-priority frames are delayed as bus load rises; jitter grows. | Bounded by the schedule, but latency is a whole poll cycle and the bus is slow. | Deterministic in the static segment once the schedule is validated; dynamic segment is best-effort. | Best-effort unless TSN is deployed end to end; switch queueing spreads the tail under load. | Fixed. Every event lands on the 1 ms grid regardless of how many zones or events. |
| Raw data rate † | 1 Mbit/s classical; up to 5-8 Mbit/s for the CAN-FD data phase. | Up to 20 kbit/s. | 10 Mbit/s per channel. | 100 Mbit/s (100BASE-T1) to 1 Gbit/s (1000BASE-T1) and beyond; 10 Mbit/s for 10BASE-T1S. | ~2.7 Mbps on the shared channel; capacity added by carriers, not by frame time. |
| Vehicle-wide state | None. Each node knows only the frames it subscribes to; a full picture is assembled in software. | None. The master holds a local view of its own slaves only. | Partial. A consistent snapshot per cycle for scheduled signals, assembled by the application. | None inherent. State is whatever the application layer (SOME/IP, DDS) builds on top. | Native. Every module holds the whole committed state vector each millisecond. |
| Compute model | Sequential. Each ECU runs its own loop against its own inbox. | Sequential, master-driven. | Sequential per ECU, coordinated by the shared schedule. | Sequential per ECU; typically a few large compute nodes plus the network. | Distributed and time-parallel: every module computes on the same state in the same window. |
| Harness impact † | A dedicated pair per bus, plus separate power. Several buses and gateways per vehicle. | Cheap per run, but many separate LIN runs add up across the body. | Two pairs per channel plus power; the most wiring-heavy of the buses. | A dedicated pair per device to a switch; switch fan-out adds harness back. | One ring carrying power and data. ~200-300 m of wiring per vehicle in ASG's own figures. |
| Fault handling | Error frames and bus-off recovery; a shorted or babbling node can take a bus down. | Minimal. The master detects a missing or malformed slave response. | Bus guardian and dual channels give redundancy against a single-channel fault. | A fault is contained to one link; the switch isolates it. No inherent actuator-level protection. | 10 us local reaction in each block acts as an electronic fuse; no relays needed. |
| Standardisation & maturity | ISO 11898. Decades of field history; the default in-vehicle bus. | ISO 17987. Mature and ubiquitous for body electronics. | ISO 17458. Proven in series production, though newer programmes lean toward Ethernet. | IEEE 802.3 / 802.1. Mature IT base; automotive profiles and TSN still consolidating. | ISO-compliant seven-layer protocol; pre-series. Standard number and assessments still to be cited. |
| Tooling & ecosystem | Vast. Every vendor, analyser and test suite supports it. | Broad and inexpensive; part of every automotive toolchain. | Established but narrower, and contracting as programmes move on. | Large and growing, drawing on the wider IT and networking industry. | Early. A public simulator; silicon, stacks and test tools are in development. |
† derivation still to be confirmed. Legacy figures are the nominal values from the published standards; ASG figures are set out on the methodology page.
Compare in detail
- ASG vs CAN / CAN-FD CAN is the arbitration-based, event-triggered serial bus at the centre of almost every vehicle built today; ASG replaces both the arbitration and the harness it needs with one synchronous ring.
- ASG vs LIN LIN is the single-wire, master-polled sub-bus for slow body electronics; ASG carries the same low-speed functions on the vehicle-wide ring with no separate network and no master node.
- ASG vs FlexRay FlexRay adds a time-triggered schedule on top of a dual-channel bus; ASG is time-triggered by construction, with one global commit per millisecond and no schedule to design.
- ASG vs Automotive Ethernet Automotive Ethernet brings switched IP networking to the vehicle backbone; ASG is a control architecture, not a transport, delivering deterministic vehicle-wide state without switches or a protocol stack.
Questions
Does ASG replace all of these?
It replaces the control buses: CAN, LIN and FlexRay. High-bandwidth Automotive Ethernet for cameras and the data backbone stays; ASG runs the control layer beneath it.
Can ASG be introduced gradually?
Yes. A zone module translates CAN, LIN or FlexRay itself, folding those sub-systems into the shared vehicle state and answering back in their own format, so the rest of the vehicle can move across one domain at a time with no separate gateway.
Where do the numbers come from?
Legacy figures are the nominal values from the published standards. ASG figures are modelled or measured values; each is set out on the methodology page.
Measure it against your own architecture
Build your vehicle in the simulator and see the harness, the control blocks and the economics for that configuration.