I found this Sparkfun video in my daily reading.
According to Pete: How CAN bus works
That and the thread CAN Bus PCBs that talked about star topology connection lead me to this link Controller Area Network Physical Layer Requirements and me doing some math which I don’t think is all that valid…
My take away we have very short buses in our robots by CAN norms and can get away with behavior that would be bad news in most cases. However you are on your own, a scope may not be enough to catch glitches that may cause problems. Even if there are problems higher layer error correction may catch it. None of that means your robot will or won’t have problems on the field.
Pete makes good video’s I recommend anyone interest in CAN or ODB look at his videos.