Terminology » Networking Basics » BroadR-Reach vs MOST vs FireWire: Key Differences

BroadR-Reach vs MOST vs FireWire: Key Differences

automotive ethernet broadr reach firewire networking technology most

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  • It has largely been superseded by Thunderbolt and USB 3.0 interfaces.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:

FeaturesBroadR-ReachMOSTFireWire
ArchitectureSwitchedShared synchronous ringShared Bus
TopologyStar, daisy chain, ring - all with optional productive redundancyRingStar, daisy chain, ring - all with optional redundancy
Bandwidth100 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)
MediumSingle UTP (Flexray or equivalent at 100 Mbps), multiple UTP/STP, coax, all types of fiber.Plastic fiber, UTPFiber and STP up to 800 Mbps, UTP to 100 Mbps, UTP up to 800 Mbps specified.
Sample Rate/Time Synch supportAny arbitrary native rates (100 ps jitter - < 1 µs synchronization)44.1 KHz native, sample rate conversion for other ratesAny arbitrary native rats (100 ps jitter - <1 µs synchronization)
DiagnosticsBuilt-in cable diagnostics that checks open, short, location of fault, quality of the medium.--
CostLow 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.