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Ethernet as System Comm Link
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nctnico:

--- Quote from: fourfathom on March 06, 2022, 05:41:36 pm ---
--- Quote from: mansaxel on March 06, 2022, 03:46:35 pm ---On timing, as you write; if we can hold packet delay variation well below the timeout value for various control function timeouts, we're good. And the extra energy spent in teaching the control program to accept data when it arrives, and not to crash/hang if it does not arrive exactly when it should (according to the TDM clock), is well invested, because it makes the control system resilient.
--- End quote ---

Yes.  And again, delay and jitter requirements in the control plane are orders of magnitude more relaxed than in the network data links.

I've been out of that loop for a long time, but I suppose in many cases now the separate "box management" control plane has evolved to being just a custom LAN within the much larger WAN.  At least that's how I would approach it (absent stuff I don't know about).  I like simplicity and uniformity.

Well I am gratified that my hunch about using switched ethernet seems to have been validated.  I've always thought I was right, and I had heard of this method being used elsewhere, but until now have never brought it up among my peers.

--- End quote ---
There are plenty of realtime ethernet protocols around. Think about modbus-tcpip or (better) Ethercat for example.

With a switch-chip in between you have buffering as well. Recently I had to resort to a bit-banged ethernet MAC (yes, you can do that) which is way way slower than a real ethernet MAC but with a switch-chip on board which does packet buffering, the actual packet loss is extremely low.

All in all, I think your solution would have worked well using simple parts.
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