RFBroadR-Reach vs MOST vs FireWire: Key Differences
automotive ethernet
broadr reach
firewire
networking technology
most
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This page compares BroadR-Reach, MOST, and FireWire, highlighting the differences between them.
BroadR-Reach
Here are the key features of BroadR-Reach:
- Uses 3-level signaling
- Full duplex communication
- Echo cancellation
- PAM-3 modulation, 66.7 MSPS, 33.3 MHz Bandwidth
- Operates over a single twisted pair cable
- Employs Decision Feedback Equalization (DFE)
The major benefits of BroadR-Reach over traditional Ethernet technologies are:
- Reduced bandwidth requirements by over 2 times.
- Operates over lower quality cabling.
- Enables aggressive filtering for improved emissions and immunity.
MOST (Media Oriented Systems Transport)
Here are the key features of MOST:
- MOST stands for Media Oriented Systems Transport.
- It’s a high-speed networking technology developed primarily for the automotive market.
- The technology can be applied both inside and outside the vehicle (e.g., a car).
- It’s used to transport audio, voice, data, and video signals over plastic optical fiber.
- The MOST serial bus uses a ring topology for connecting devices.
- Up to approximately 64 devices can be connected in a ring network.
- Communication over the MOST bus is synchronous.
- Common versions include MOST25, MOST50, and MOST150.
FireWire
Here are the key features of FireWire:
- It’s a serial bus standard used for high-speed communications and isochronous real-time data transfer.
- It’s defined in the IEEE 1394 standard.
- Available with copper cable, Cat-5 cable, and optical fiber versions.
- Offers a distance of about 4.5 meters with copper cable.
- Supports data rates from 400 to 3200 Mbps.
- Supports daisy chains with up to 63 devices.
- It has largely been superseded by Thunderbolt and USB 3.0 interfaces.
Difference between BroadR-Reach, MOST, and FireWire
The following table summarizes the differences between BroadR-Reach, MOST, and FireWire:
| Features | BroadR-Reach | MOST | FireWire |
|---|---|---|---|
| Architecture | Switched | Shared synchronous ring | Shared Bus |
| Topology | Star, daisy chain, ring - all with optional productive redundancy | Ring | Star, daisy chain, ring - all with optional redundancy |
| Bandwidth | 100 Mbps, 1000 Mbps, 10 Gbps widely deployed - 40/100 Gbps in development - Many other rates used in private networks (per link) | 25 Mbps common, 150 Mbps in early deployment (shared) | 100, 200, 400, 800 Mbps widely deployed - 1.6 Gbps in prototype, 3.2 Gbps specified (Shared) |
| Medium | Single UTP (Flexray or equivalent at 100 Mbps), multiple UTP/STP, coax, all types of fiber. | Plastic fiber, UTP | Fiber and STP up to 800 Mbps, UTP to 100 Mbps, UTP up to 800 Mbps specified. |
| Sample Rate/Time Synch support | Any arbitrary native rates (100 ps jitter - < 1 µs synchronization) | 44.1 KHz native, sample rate conversion for other rates | Any arbitrary native rats (100 ps jitter - <1 µs synchronization) |
| Diagnostics | Built-in cable diagnostics that checks open, short, location of fault, quality of the medium. | - | - |
| Cost | Low cost, approaching analog system, many billions of ports deployed. | Higher, less than a million ports deployed. | Higher, no deployment, but over one billion 1394 ports |
Refer to the features of automotive Ethernet and its requirement in automotive vehicles.
