3 ms·

It likely depends heavily on which aircraft we're talking about. The new 787 is highly computerized. It would not surprise me to learn everything is on the sa

by na85 12y ago

It likely depends heavily on which aircraft we're talking about. The new 787 is highly computerized. It would not surprise me to learn everything is on the same network and only segmented in software.

sukilot 11y ago
The FAA would be deeply surprised that such a thing evaded their notice, if true.
neurotech1 11y ago
The 787 uses multiple isolated networks. The In-Flight Entertainment network is regular Ethernet, and Flight Management System is a different format (ARINC 664/AFDX) which provides deterministic real-time connectivity. There is a device called a Network Extension Device (NED) which is a one-way gateway between the FMS and the IFE for showing the progress of the flight to passengers.
- koonsolo 11y ago
  First you say it uses isolated networks, but then you say NED connects the two? How does it enforce the 'one-way'?
  - neurotech1 11y ago
    There is multiple networks for the various aircraft systems not a single network. The NED for the IFE doesn't physically have the wires for two-way connectivity to the aircraft FMS network.
  - vidarh 11y ago
    With no knowledge of how these systems are actually implemented for aircraft, for various values of "isolated": I once had a customer that provided energy pricing data from their network via a leased line to be put onto their website. In their case the isolation they required was provided by not running any network stack over that link - they sent a mostly raw (error correction but that was it) stream of data point to point rather than network packets, and the connection was entirely one-way - if we were to try to send anything back, nothing was listening. Making it physically impossible for something to listen is reasonably straight forward if you control the hardware, and you can easily additionally electrically isolate the networks.
  - EliRivers 11y ago
    While I have no idea how they do it, I used to do it with one of these: https://en.wikipedia.org/wiki/Opto-isolator https://en.wikipedia.org/wiki/Opto-isolator One circuit emits light, the other circuit listens to the pattern.

by na85 12y ago

sukilot 11y ago

The FAA would be deeply surprised that such a thing evaded their notice, if true.

neurotech1 11y ago

The 787 uses multiple isolated networks. The In-Flight Entertainment network is regular Ethernet, and Flight Management System is a different format (ARINC 664/AFDX) which provides deterministic real-time connectivity. There is a device called a Network Extension Device (NED) which is a one-way gateway between the FMS and the IFE for showing the progress of the flight to passengers.

koonsolo 11y ago
First you say it uses isolated networks, but then you say NED connects the two? How does it enforce the 'one-way'?
- neurotech1 11y ago
  There is multiple networks for the various aircraft systems not a single network. The NED for the IFE doesn't physically have the wires for two-way connectivity to the aircraft FMS network.
- vidarh 11y ago
  With no knowledge of how these systems are actually implemented for aircraft, for various values of "isolated": I once had a customer that provided energy pricing data from their network via a leased line to be put onto their website. In their case the isolation they required was provided by not running any network stack over that link - they sent a mostly raw (error correction but that was it) stream of data point to point rather than network packets, and the connection was entirely one-way - if we were to try to send anything back, nothing was listening. Making it physically impossible for something to listen is reasonably straight forward if you control the hardware, and you can easily additionally electrically isolate the networks.
- EliRivers 11y ago
  While I have no idea how they do it, I used to do it with one of these: https://en.wikipedia.org/wiki/Opto-isolator https://en.wikipedia.org/wiki/Opto-isolator One circuit emits light, the other circuit listens to the pattern.